U.S. Army Cancels Interim Combat Service Rifle (ICSR) Program

Last week, The Shooter’s Log ran a throwback article on the Top 5 Combat Rifles of All Time. The debate was lively to say the least, but the one overarching theme was a feeling that the 5.56 simply did not have enough punch. The U.S. Army seems to agree. So, last August, the Army announced the Interim Combat Service Rifle (ICSR) program. The ICSR was tasked with replacing the Army’s M4 carbine with a 7.62 mm rifle. A month later, the program was canceled.

Multicam in Afghanistan

In truth, much criticism of 5.56 is misplaced. That is not an argument for the 5.56, just an observation that most readers’ criticism does not match the Army’s. Like most readers, the Army is concerned with the power of the 5.56×45, but not in the way most who have offered comments seem to believe. The 5.56×45 has plenty of lethality. NATO required a 62-grain bullet to ensure it would penetrate a steel helmet at 600 meters. The original 55-grain tested was considered inhumane and believed to do too much damage. The 5.56×45 is lethal to be sure.

The Army’s desire to abandon the 5.56×45 in favor of a 7.62 mm round was two-fold. First, the army wanted a cartridge with greater stopping power at a longer range than the 5.56×45 offers. It also needs a round that provides better penetration through modern body armor. This fact echoes critics’ claims that “The 5.56×45 does not have the distance or lethality needed for modern small unit tactics, especially after upgraded body armor has been shown to be able to defeat the 5.56 mm round.” However, as the program’s title declared, the 7.62 mm was only supposed to be an “interim” solution. The U.S. Army has another program that is actively developing an intermediate caliber round and rifle combination that would fall between 5.56 mm and 7.62 mm, giving soldiers greater range than their current weapon and greater power and penetration.

If you were tasked with coming up with a new rifle round for soldiers that fell between the 5.56×45 and 7.62 mm, what would you choose? What rifle, or rifle characteristics, would you mandate? Share your answers in the comment section.


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Comments (74)

  1. I was looking for an AR platform that was chambered in 243 winchester but the only ones i found were over $1200.00. I don’t understand other than the popularity of the 5.56, that could drive the price up that much, I can get a AR15 / AR10 for around $600.00.

  2. Someone does not like my comments. I just sent one in and now all of a sudden my password no longer works.

    I guess freedom of Speech no longer works on Shooters Log. I felt like I had a voice and was considered equal with my brothers who enjoy shooting. Now I am not so sure.


  3. That seems odd to me. The 6.5 Grendel out shoots the Creedmore, as well as the old WWI 6.5 Carcano and matches while nearly passing the 6.5 x 55 Swede. The main problem they are having it modern thought process. Most specs do not want to exceed 140 grain bullets. The European military specs shot 160 gr Round Nose. The 160 gr is long and balances well, also maintains the energy. But US Military will not accept anything proven by others. The 7.35 mm Carcano was the worst round I ever worked with in reloading, no way to get good accuracy with it, but the 6.5 because of different shape ballistics worked better. The old 06 is still my preference! But it won’t cycle like the military wants or needs.

  4. The Army did the initial work, and came up with the 6.8 SPC, though they blew the chamber dimensions. the 6.5 was rejected for poor terminal performance, and had they chambered the 6.8 correctly there would not have been random pressure spikes, causing the round to have to be loaded down. The firearms industry took over and introduced the 6.8 SPC II. basically rechambered and loaded up.. then cam the improvement I bought from AR performance, the 6.8 ARP. Similar to the improvement over the .223 rem (.223 Wilde) it gives decent velocity from 130 gr. 277 bullets. all fitting in the ar15 platform.
    this round would fill the bill.

  5. Why not take it up to 6.5mm and produce a 223 variant similar to the 6.5 mm Grundel?

    I have had years experience loading 6.5 x 55 Swede, 6.5mm Japanese, and such. Odd how today we basically duplicate these in the 6.5 Creedmore. So why not a 6.5 x 45 mm?

  6. All the belligerents of WWII had infantry weapons that produced muzzle energy well in excess of 2000 ft. lbs. These include 30-06, 7.62X54 Mosin, 8X57 Mauser, .303 Enfield, 6.5 and 7.7 Jap, and others.

    Toward the end of that conflict, the Germans decided perhaps a somewhat less powerful cartridge in a rifle that shot in both semi and full auto mode would be better for dealing with the Russian hordes advancing on their homeland. They shortened their 8X57 rifle round to 8X33, and developed the STG. 44 select fire rifle to use the new round.This was the very successful birth of the “assault rifle” and “intermediate” power rifle round.

    The Russians after being shot at with the new Nazi weapon and round realized the Germans had something good, and shortened their own rifle round to 7.62X39MM. They developed first the SKS carbine, and then the AK-47. So far somewhere in excess of 60 million AK’s have been made.

    My point in this bit of history is to say a modern “assault rifle” needs an “Intermediate” round, not a full power rifle round, like the .308. The round needs to be suitable for full auto controlled fire, by a normally trained soldier or marine.

    A US individual soldiers weapon and cartridge must: 1. Be light and handy for urban combat. 2. Fire a cartridge that has adequate, not excessive, stopping power. 3. The round should be lethal and accurate out to “normal” engagement ranges; say 600 M. 4. The cartridge should feed perfectly in existing or newly designed mags. These mags should hold a minimum of 30 rnds. 5. Cartridge should be light weight for maximum ease of carry. Mags should be easily reloaded by hand or with stripper clips. 6. If possible, new cartridge and magazine should work in the current M-16/M-4 platform, using a cartridge of the same bolt head diameter as the current 5.56 case; only a new barrel should be required to enable use of the new round in current rifles and carbines.

    Our 5.56X45 M109 cartridge almost works. A necked up to 6MM or so could be easily be made to work. I envision a cartridge based on our 5.56 case, necked to 6MM, and firing an aerodynamic bullet of 90 to 110 grains that would remain supersonic to 800M or more.The cartridge would have a velocity of 2500-2600FPS at the muzzle and have a muzzle energy of 1300-1600 ft. lbs. There, done!

    This isn’t rocket science, it’s just common sense. Our military, though, doesn’t ask for my opinion. They will take 20 years and several billions of our dollars to come up with their own cartridge that will be lousy.

  7. Yep, that would work. It already does work and its called the .260 Remington. Several companies already make brass and ammunition for it. It will fit M14/M1a actions and AR10 actions. It will fit any short action rifle with a standard bolt face. It is a necked down .308 Winchester casing utilizing the 6.5 cal. bullet (.264). It is the ballistic twin of the 6.5 Creedmoor, with a little more case capacity. On a different note, those of you who are fans of the AKM/AK47 type actions, the Israeli Galil in its larger version uses the 7.62X51 Nato, is highly accurate, uses an improved AK action, and is adaptable to any standard cartridge of the .308 family. The FN as suggested above is also a viable option. None of the cartridges that will fit in the M16 length actions will meet the criteria of penetrating body armor at 300 meters and beyond while giving incapacitating wounds at 300 meters and beyond. The 6.8 and the 6.5 Grindel are just the best that can be made to fit inside an AR15 platform. They remain light for caliber and defecient in mass and energy for penetrating body armor at distance, and have a noticeable lack of wounding capability at distance when compared with anything using a short action case such as the 7.62X51 or the .30 Thompson Center which is the parent of the 6.5 Creedmoor. The 7.62 X39 is also similarly limited by bullet mass, velocity and bullet weight. Remember the criteria: penetration of body armor at 500-600 meters and incapacitating wounding at the same distances.

  8. It don’t take a genius to figure this one out. A 6.5 projectile fired from a case the capacity of the 7.62, short and fat.
    Think bench rest weapon goes to war.
    The 6.5 is proving its superior ballistics every day at long distances. The 6.5 JDJ chambered in a Thomson Contender has killed everything on the planet. I can attest to the 6.5 abilities at great distances to hit the target. Just select the type of projectile for the job and work up the best case design and you will have the perfect tool for the job.

    1. The 25-06 is a bit too long for cycling rates. While I am a fan of the 30-06 and feel it is the best hunting round the military proved years ago that the 7.62×51 meets the specs with a shorter throw.

  9. I’ve read a number of the new comments on this subject, and again most of the comments are on the lines of how to get the M16 platform to perform like an AR10/M1A/M14. I have with me two different reloading manuals for various cartridges, which range from 17 cal. up to Browning Cal. 50 Machine gun. In the 223/5.56 X 45 cartridge alone, one manual lists over 200 loads, going from 35 grain bullets up to the Sierra 90 grain projectile. The 90 grain projectile is so long that it takes up a significant portion of the case capacity, and will get no more than 2550 fps out of a 24 inch barrel. The bullet requires a 1 in 6.5 inch twist in a 24 inch barrel. The M16 A3 has a 1 in 7 twist and a 20 inch barrel, which means that this loading loses at least 100 fps. In a short barreled M4 with a 16 inch barrel, it would be doing good to break 2350fps at the muzzle. Setting the bullet out in the casing won’t work either, because it must fit inside a standard length magazine and magazine well. The 6.8 won’t meet the penetration and wounding criteria at 500 to 600 meters either. The 6.8 Spc wouldn’t meet the criteria, either. The best the load data can do with the heaviest bullet the casing can handle without compromising its powder capacity is 2600 with a 115 grain Sierra. The 6.5 Grendel is also limited with the requirement to fit inside an M16 magazine. The heaviest bullet it will handle is 123 grains and that just breaks 2500fps. All these velocities are for 24 inch barrels, and all are MAXIMUM charges. In a 20 inch barreled standard M16A3 all these rounds lose about 100 fps. and around 200 fps in a 16 inch barrel. The only way around this is to have a larger cartridge and a longer overall length action so that the platform can accomodate heavier bullets. The key to penetration and wounding outside 300 meters is mass. Example: A 22-250 will generate around 1570 ftlbs per sq in. The 45-70 with a factory 405 grain bullet at a factory velocity of about 1300 fps will generate about the same energy at 1540 ftlbs per sq in. The 22-250 round will not even get a 600lb bear’s attention while the 45-70 bullet will probably go through him length-wise. The heavier bullet retains its energy and penetrates at distance. I would not go lighter in caliber than .308 and lighter in weight than 168gr. for the penetration at distance and wounding at distance, with a preference toward the 175 grain Sierra, but if the Army is going to go to a different caliber and meet or get near to meeting these criteria, I would recommend the 260 Remington with 140 to 147 gr. bullet or the 6.5 Creedmoor in the same bullet weights. Anything smaller or lighter will not have enough mass and energy retention to penetrate a vest outside 300 meters or create enough blunt trauma to the wearer of the vest to incapacitate him. Example: the 5.56X45 firing a 77gr. bullet at 2800fps from a 24in. barrel has a MV of 1300 fps at 600 yards (551 meters) and energy of about 280 ftlbs. This is effectively the same as shooting a man in a vest with a 22 longrifle round at 25 yards from a rifle. The 45-70 at 1300fps at the muzzle has a retained velocity of only 830fps at 600 yards, a trajectory like a rainbow, and retained energy 620 ftlbs. The 6.5 bullet at 2700fps (.260 Rem. or 6.5 Creedmoor) has a velocity at 600 yards of about 1900fps and energy of about 1140 ftlbs. The 7.62 Nato has a max muzzle velocity of about 2750fps with a 175 grain bullet (24 in. barrel), a velocity of approximately 1820fps and 1280 ftlbs at 600 yards. Nothing that shoots in the M16 will be able to shoot flat enough and have the sectional density or mass to get penetration or good wound characteristics at 600 yards. It requires a different platform and a different round to do this. And the best combination of low recoil and high downrange energy is still the 7.62, with both the above 6.5’s as the best alternatives.

  10. I built a 7.62X39 with the same size AR lower.The barrel is 16″ with a 1.10 twist and it weighed in at 6.62 lbs. that is basically the same round we are competing against in the middle east. This caliber is battle proven in AK platform for decades. With tighter tolerance barrels and and ammo production in the AR platform it could a very economical intermediate battle rifle.

  11. The 6.8 SPC is an excellent choice for the ICSR option. The round has already proven itself with operators in all types of environments. 80% stopping power of the 7.62 with excellent ballistic characteristics and will work with all current multi caliber mil-spec rifles in inventory. Just a barrel and mag change would bring them the punch they need.

  12. .243 Winchester … easily necked up to or down from 7mm-08 or .308 on the cartridges from which it is based. Less weight in 1000 rounds and should save on existing magazines and minimal tooling changes for existing barrels and chambers. Easily lethal on human targets and arguably for any North American game.

    1. The 24 cal or 6mm leads are limited to bullets under 105 grains. 6.5 mm allows a larger range of bullets and has proven itself over the years in ammo calibers such as the 6.5v55 Swedish, 6.5 Arisaka,, as well as the European sporting round 6.5x57mm. To me the 6.5 Creedmore needs longer time in service as a hunting/target rifle round. The 260 Remington has proved itself in hunting rifles with a larger choice of bullet weights. I am still a fan of the 7.62×51.

  13. Best in my opinion is a 300 Blackout with a 95 grain. 2400 plus feet per second, not bad at distances, hard hitting, light recoil and easy modifications for the M4.

  14. 6.8 SPC. 50% more energy than the 5.56 but still functions through a milspec sized rifle. It’s the perfect comprise between power and weight and falls evenly between the 7.62 and 5.56. It was specifically developed for exactly this purpose. Remington’s inaccurate SAAMI specs hurt its commercial acceptance but it’s performance is outstanding.

  15. To use the same lowers, which would save a lot of $, the 6.5 Grendel would work well. If a total re-do is warranted, had to beat the 260 Rem. Less logistical cost = 308 brass necked down. 6.5 Creedmore is good, but higher overall cost than the 260 and no ballistic advantage worth mentioning.

  16. I keep seeing 6.5 showing up here, but for a combat weapon, its about the worst possible choice. the Grendel is too large for the bolt face in the M4,
    while civilians use it, on SEMI auto, and in limited doses, the bolt face is too weak to support full auto, or heavy sustained fire without bolt head failure on a grand scheme. the Creedmoor is a poor mans 260 rem, and therefore requiring a 10 – 11 lb weapon. and its shorter than the .308 or 260 and therefore will not be reliable in an action designed for the .308 under battle conditions malfunctions are all but assured.
    the 6.5 rears it head from time to time and goes away ALWAYS, because even though it is VERY accurate, and even a poor marksman can shoot it well the high ballistic coefficient which is responsible for its aerodynamic flight giving it excellent long range capability ON PAPER and SMALL game it travels through flesh easily as well offering poor terminal ballistics. the military is forced to use full metal jackets so expantion is not on the table, as a civilian shooter bullet construction is controllable, but still that which performs well at 600 yards is useless at 50 yards. the 264 mag was popular, until enough field time showed performance on game was spotty and barrel life sucked, then came the 260, same thing it took off, until mulies sometimes ran off with good hits
    then the creedmoor. advertising hype, and in a few years, as people who bought into it realize true performance on game is marginal, back to the .308, a round that penetrates doors and structures in urban combat without much deflection, PROVEN combat performance, and a well rounded battle rifle cartridge, that coupled with the M4 converted to 300 Blackout gives ground forces 2, 30 cal weapons capable of performing battle, and special duty.

  17. Hands down it has to be 6.5 Creedmoor. Superior down range ballistics after 600 meters as compared to 7.62 x 51. Coupled with shooter friendly recoil it is a great round.

  18. I love how relevant some of your articles are, and I enjoy reading them. With that wrote; I knew that the 7.62 was only temporary, and thought I read somewhere that the 6.5 Creedmoor was in the Army’s sights. That round is an excellent replacement, considering it would make it very common, and enable it to become less expensive for civilians. As of now, it isn’t very budget friendly.

  19. I love my mauser 98k. The 8mm Mauser is amazing I propose that we simply switch to a 7.92×45 round. this round will fit into all 7.62×51 magazines and only requires a new barrel.

  20. The US Military sh0uld try the 300 blackout, which has more punch, more killing power, longer range, larger bullet mass. They could save millions by just replacing barrels. Even the magazines will stay the same.

  21. The 6.5 Grendel has greater cross sectional density; therefore, greater range and ability to penetrate body armor. Only requires a new barrel. Satisfying several requirements with one upgrade. Better than going all the way out to 7.62X51mm and retains most of the cost and weight advantages of the 5.56X45mm NATO round.

    Let me know what you think of my idea in kind words please.


    1. Mike, I agree with your Grendel approach but thought you also need a matched BCG and Mag.

  22. 7-TCU is a no-brainer ! The only change needed is a barrel change. BCs greatly increased for more lethality at distance, diameter increase exponentially increases terminal performance, zero recoil increase and a very low increase in ammunition weight = no brainer. When you hear stupid, think government.

  23. It’s probably being driven by politics.
    Especially after recent events.
    I deal with DOD Aquisitions 40+ hours a week. These caliber / projectile arguments will go on forever. instead of taking something commonly used, they’ll probably come up with something new that will cost billions in new tooling and guess who will pay for it? A decade or 2 later, they might just do like the FBI just did and go back to an old round. And we will pay for it again.

  24. 6.8 SPC. It would require a barrel change and not a new rifle. Also mags to fit the slight difference and fit of this round. And the R&D is allready done for this round. Its also already in production.Only a slight reduction in rounds count,and lighter than 7.62.

  25. The 6.5 Grendel is a perfect choice, lighter than 7.62 NATO, better range and accuracy than the same. With 3 uppers all bases will be covered, close quarter, snipe and infantry purpose. This will out class the 5.56 and save tax payers money.

  26. As far as lethality is concerned any of the 6 bullet diameter are great but let’s get real when we talk accuracy and the everyday grunt.
    At present our NATO round is good in an expert’s hands and scoped is damn deadly and taking environmental conditions in considerations very accurate up to 600 meters.
    Our 30 cal NATO is lethal and accurate to 800, but still with it scoped one needs a special degreed base to reach out further., and once againndamned few grunts especially in combat are lucky to hit the proverbial barn door with it.
    As one of Viet Era grunts it was only because of my PRE service skill that I easily qualified expert, and could reach out to 600 easily with peep.
    Club of an M 14 tho was most assuredly more accurate than those M16’s.
    DAMN lot of little yellow fellows died even with the I’d up rounds and weapon.
    Today’s m4 battle rifle has killed way way many more than in Nam and way way less US casualties per killed.
    Body armor: what enemy are we fighting that has body armored even at Kevlar 3?
    He.. we are fighting militia civilians not national troops.
    Our armor can take anything that any major nation weapons fire under the 300 Lap.
    CERAmic plates such as those developed in Netherlands even dissipate the blunt force of our old 30 06 armor piercing , while saving weight
    C’mon now how large is the target when trying to use peep and front site post at 600 meters?
    Which military NATO 55 or 62 grn with current m4 twist rate is most accurate with mil spec rnds?

  27. Redesign the bolt in the m4/m16! Go to a 7.62×51. This will be used by our infantry and let spec ops carry for the mission!

  28. I would suggest either a 6.5 mm or 7 mm which would fall in between the 5.56 and the 7.62 (6.59 actual median). Both are relatively flat shooting bullets. The 6.5 has greater sectional density for equal weight bullets, but the 7 mm can used heaver bullets for more penetration. I have used the 7 mm for many deer and elk with fantastic results.

    1. Mr. Tillman and Mr. Smith both have the right idea. Penetration is a combination of velocity and mass. A heavy for caliber .223 bullet isn’t going to have the penetration potential that a heavy for caliber 6.5 or 7mm bullet has. At 500 meters (545 yards) a bullet fired at 2700 fps with a BC of around .5 is doing around 1800fps. Penetration is going to depend more on mass, density and inertia than velocity. A bullet of less than 130 grains and small diameter is not going to penetrate well, and it won’t get the wound channel that a larger caliber bullet will. The .300 Blackout starts with too low a velocity and too light a projectile for the criteria laid out. Remember, the criteria are: penetrate body armor at 450-550 meters and retain enough energy/velocity to create incapacitating or killing wounds at that distance after penetrating the armor. Also, there is a lower limit to the effectiveness of the heavy for caliber projectile. A 90 grain .223 bullet is only massive when compared with other .223 projectiles and some of the medium caliber (.243/.257) projectiles. As an example of what I’m talking about, I shoot a .35 Whelen. My projectiles weigh 225 grains and 250 grains. They are moving 2725 fps and 2685 fps 10 feet from my rifle muzzle. At 500 yards the 250 grain bullet with a BC of .42 is doing 1750 fps and has 1640 ftlbs of energy. Blunt trauma alone will incapacitate the target whether or not the armor is breached. The mass of the bullet causes greater energy delivery. The 225 grain Sierra at 2725 fps delivers a velocity of 1700 at 500 yards, and 1700 ftlbs. The mass of these bullets combined with their inertia would insure a high wounding capacity at distance even without armor penetration. The impact would break ribs, crack sternums and rupture soft organs such as spleens and livers. It would do this without penetration of the armor. Its a simple physics equation. The heavier the bullet, the greater the inertia/retained energy. So a 6.5 140grain bullet is always going to be more effective at distance than a 5.56/.223 bullet, given comparable starting velocities. Also, while we’re discussing this, we’re talking about a cost effective way to meet these criteria while being accurate enough for a good rifleman to register hits at 500 meters. The smallest caliber that will do this is the .264/6.5mm in the short action cartridges. 6.5 Creedmoor and .260 Remington, or the 6.5×55 They would also be the easiest on trainees due to lower recoil for required penetration at distance. The 7mm-08 would also work, using a 150 to 165 grain bullet. I would not recommend steel cored bullets due to accuracy issues and lower density. Steel or Titanium tipped bullets might be ok, but they would be more expensive. However, the Army has new platforms for the 7.62×51 round which are accurate with match grade ammunition to 900/1000 meters, and with the 175 grain competition bullets that Speer, Sierra, Nosler and Hornaday make, velocities at the muzzle of a 22 inch barrelled M1A or M2010 (AR10 without the problems) are around 2550 to 2600fps. The bullet is supersonic to around 900+ meters, has greater mass and thus more inertia, penetration and wound potential at 500 meters than any of the smaller calibers. And we already have plenty of weapons for it. I would just order the new AR10 type rifle that is being fielded in 7.62 Nato currently with barrel lengths of 18, 20 and 24 inches and use a 168 to 175 grain bullet. Also, to hit at 500+ meters, the ammunition will have to be match-grade. But if we must change calibers/rounds, the round must have a heavy enough bullet and a large enough caliber to have enough mass to get penetration at distance, it has to be able to launch a heavy (140grain or greater)projectile at at least 2550fps from a 20-22 inch barrel, and it has to be accurate to at least 600 meters, with a recoil low enough to be user friendly and a weight of 7.5 to 8.5 lbs. None of the rounds that are compatible with the AR15 will meet these criteria. For compatibility and ease of manufacture, I’d go with the 260 Remington or the 7mm-08 because the only change needed in an AR10 type rifle or an M1A/M14 is a barrel sleeve/new barrel. And the cartridge for either of these rounds is just a necked down 7.62X51 so the ammunition is easy to make.

  29. I bought the SIG 716 Patrol about 2 years ago. I think it’s perfect because it’s an identical AR system in 7.62 NATO. Mine is the OD version. Everything that one is use to, accept the mags are different size.

    I’m a big fan of the TAVOR now as well, but that would have to be made into 7.62 as well. Currently it’s 5.56 and 9mm.

  30. 6.8spc. It’s already been verified to be a great round in the M4 platform. Very few mods needed to get it in mass production.

  31. A heavy-for-caliber bullet would provide better range and penetration, regardless of which cartridge is selected or developed. If the desire is to keep the combat load as light as possible, then updating the 5.56 cartridge would seem like the best solution, rather than adopting a larger, heavier round. In the current AR15 platform the 5.56×45 can be loaded with a projectile that weighs about 77 grains. A heavier bullet in the 90 grain range has the potential to provide greater “punch”, but it is not currently feasible unless the receiver is stretched. This would create a bulkier, heavier rifle, which is undesirable. Alternately, a larger diameter case could be employed so that the bullet could be set back inside the case, while simultaneously allowing sufficient room for enough powder to produce the required ballistic performance. The primary drawback here is the likely reduction of magazine capacity by 10-15%. A third alternative might be feasible if a long projectile could be seated deeper inside the case. This would require improved powder performance to offset the reduced powder capacity. In theory, the extra weight of the 90 grain projectile might be offset by employing lighter casings made of polymers or exotic metals, or possibly even semi-consumable cases. This third approach may prove technically unfeasible or cost-prohibitive, but I suspect some research in this area is contemplated, if not already underway.

  32. I would choose the 300 Blackout, loaded with 110 gr bullets, it is equal to, or superior to the 7.62×39 and has more energy @ 500 meters than the 5,56 nato. loded with 230 gr bullets, subsonic, it is a perfect choice for surpressed fire, and with a simple barrel swap, the M-4 is converted.

    1. Interesting comment except that it completely ignores the fact that regular army infantry don’t use suppressed rifles and without utilizing that express purpose there numerous other cartridges that provide superior ballistics to the 300 blackout.

  33. I think the 6.5 grendle would be a good contender. there are already ammo made by several companies, including wolf. so ammo would not be a concern. the round have more penetrating power then the 5.56 and its accurate out to 500 yards or better. there are parts available and the base receiver can still be used just change out the barrel and you’re good to go.

  34. I don’t think there should be an in between choice. My vote would be straight to 7,62. When they dropped the M14 for the M16 that did not go over well as history tells us. Anyway 7.62 all the way and i would bump up the SAW to a larger caliber to balance out the squad’s firepower. With all the technology out there they could come up with something for the SAW. Just trying to help. I know i would want more knock down power.

  35. I have a bolt action chambered in 243 as well as 308 and had an AR15 in 223.
    The AR is very fast handling and fast on target and the slightly heavier 308 versions are too.
    The 223 however does stay on target noticeably better during successive firing.
    I actually find that the 243 is a generally superior cartridge to the 308.
    The 243 is a necked down 308 and delivers noticeably superior ballistic performance adding 100 or even 200 yards beyond the 308s effective range.
    Meaning the 243 is a bit more accurate at any distance than the 308 as well.
    Blast and recoil of the 308 and 243 are similar.
    If you want to go to a cartridge heavier than 223 that still doesn’t cause recoil problems for normal infantry soldiers, the 243 would be an excellent choice.
    A side bonus is that facilities making 308 are very easy to modify for making 243.
    Going to anything bigger than the 223 does mean you really need to train soldiers how to hit what they are aiming at on single fire.
    Full auto on either the 308 or 243 is not easily tamed by your average soldier.
    Probably the main advantage of the 223 is that you can actually keep the rifle aimed pretty much where you want it on full auto.
    Easily for burst and with practice on full.

  36. Critical thinking is a big focus these days. Well, here is some critical thinking in regards to lethality. Our equipment investments are only an advantage to us If we are the only ones to have them. If the enemy has advanced body armor that we have to develop rounds and individual weapons to defeat, the enemy is doing the same for their troops. They will make that ordnance available to the smaller players of the world. In turn, we will make more advanced and heavier armor. In turn, they will devise better penetrating ammo. It may soon be coming to the point that body armor is decreasing lethality. I know that when it comes to picking up out of a hole and hauling tail to another fighting position, body armor with ESAPI and DAPS drastically reduces speed. It also inhibits ones ability to ground-and-pound in hand-to-hand combat. As well, it hinders ones abity to hastily evacuate a vehicle that has caught on fire, get to a covered/concealed position in a hurry and take up a fighting position. If rounds are going to continue to evolve in their penetrating lethality and the plausibility that a Soldier’s armor is going go be penetrated anyway, at what point do we stop wearing body armor and return mobility and lethality to the individual? Maybe that way, if a Soldier survives the war and various deployments, he or she will return with half a spine that is still able to support their upper body and allow him or her to function as a working and productive member of society free of neck and back pain from all the spinal compression that results from wearing heavy body armor for months on end.

  37. If the military is going to stick with the AR-15 Platform, my preference would have to be the 6.5 Grendel. The cartridge is smaller than he .308 and will stay supersonic past 1000 meters with the 123 grain bullet. Match barrels behind a good shooter can hold sub MOA groups at that distance. Switching the bolt and barrel along with a slight magazine change on the AR-15 would be a cost savings compared to switching to an AR-10 platform. A lot of good calibers have been mentioned in this forum. The Grendel would be my preference if my life was on the line.

  38. 6.5 Grendel for shorter / lighter cartridges is better at longer ranges than 6.8 SPC or 300 Blackout, although both are a bit better at close range… 6.5 Creedmoor is more the size of a 7.62 round, it’s the obvious choice for the larger round profile.

  39. Why does it have to be a new caliber ? That means refitting an entire military force , also causing problems with resupply from allies that “still” use 5.56 or 7.62 . Make a better cartridge that fires from the same / current weapons and magazines : IE , Heavier bullet in 5.56 ?? , Lighter Bullet with steel penetrator >7.62 ? how about lighter Lighter ammunition for the 7.62 ( aluminum casing ? Blazer did it before , and it’s not like the Military reloads the shells left in the field, so why does it HAVE to be brass ? )

  40. I would agree the 6.5 creedmore would be the way to go. With lighter, bulk ammo weights than the 7.62 to carry. Plus the ability to reach out at longer distances with so much more accuracy is also a plus. The added bullet weight, and profile should get the penitration needed in the field. Way less recoil than 7.62 means faster recovery rate for follow up shots. The bullet drop on the 5.56 is just too much for many of the missions these days. A modern round for a modern military!

  41. 7.62 all the way. The AR 10 is the same size as the M16/M4 and has the distance and stopping power needed. Teach our troops how to shoot. The Air Force has a 4 hour classroom and then out to the range in Basic training. Not enough time to learn proper marksmanship.n All show adopt the USMC marksmanship training. Then all of our troops would know how to hit what they aim at.

    1. .300 Blackout would only be good for Spec Ops CQB and night ops ( suppressed ) where shots wouldbe inside 150 yards . That round is NOT a sniper round in the least . I believe they are desiring a 6.5 type that could use the current AR/Stanag mags from 5.56 , of AR10 types wit minimal modification/retooling . One of these responses is very factual and the .260 Remingtion fits the parameters.

  42. The 6.8SPC is a medium choice between the 5.56 and the 7.62. It is a .270 caliber bullet and has a trajectory close to the 7.62 (.308) so mildot scopes can be used for both calibers. The 6.8SPC has more punch and greater terminal velocity at longer yardage than the 5.56. It was developed in Afghanistan and designed to seriously wound or kill where the 5.56 would only lightly wound allowing the enemy to continue to fight.

    1. I would like to see them. Go with a 7MM rem mag. Make them all snipers like the Marines

  43. I think the Army is totally missing the point. Here is what I know for fact. Almost all of these kids cant hit the broad side of a barn. That is the truth. My son is in the Army and has told me of all the hours on the range because the majority of these guys cant qualify with an M4 let alone the M249. If they cant handle that they cant handle anything bigger. Its terrible their training isnt better. Just my 2 cents.

  44. The question is also whether the AR-15 rifle is kept.
    If kept, there are off-the-shelf 6.5mm rounds that would only require a barrel change; bolt and mags stay the same.
    If an AR-10 base is adopted, 7mm rounds come into play.
    6.8 looses aerodynamics down range.

  45. Well, you list two criteria in your article, range and penetration with lethality. In particular, penetration of newer types of body armor at distance. Both criteria are met by sufficient velocity and density of the projectile. But as the range increases, velocity drops off, so penetration and lethality depend more and more on density, or the mass of the bullet.
    If we review bullet density for the various calibers, there are three sweet spots where bullets are dense and heavy for caliber, thus retaining penetration and velocity at distance. By the way, the .308 isn’t one of them. They are the 6.5mm/264 family of bullets, the 7mm/.284 family of bullets and the .338 family of bullets. Looking in my Lee reloading manual. the 260 Remington and the 6.5X55 Mauser can be loaded with up to a 160 grain bullet. Maximum velocities range from 2550 to 2580fps. Sierra shows their 142 grain Matchking in .264 to have a sectional density of .291, and a BC of about .600. The Nosler Custom competition shows their 140 grain offering to have a BC of .529. Speer also makes a 6.5 140gr. Spitzer. Sectional density is .287, with a BC of .487. It loses a little to the other two bullets due to being a flat base. These bullets reach a velocity of between 2750 and 2800fps in the two rounds listed above.(the 260 Remington is a ballistic twin of the 6.5 Creedmoor.) Hornaday makes a 147 grain 6.5 with a density of ..301 and a BC of .697. The 7mm/284 cal. bullets are also heavy for caliber, but are not short-action cartridge friendly, and the .338 bullets are also heavy for caliber, which is why the .338 Lapua is so popular with long range shooters, but the heavier bullets in this caliber are not at all friendly to short action rounds. The 6.5/.264 cal. rounds however, have a happy combination of being very shooter friendly(low recoil) in the short action cartridges and good velocity with high weight/BC/density bullets, which means they will give greater penetration at distance while keeping a reasonable trajectory and staying supersonic out to at least 950 meters. Both the Creedmoor and the .260 Remington would easily fit into any of the AR10 or 700 Rem. Short action platforms and would be easily adapted to the M1A.(the cartridge bolt faces are the same). They would also be low recoil rounds so troops could be trained to shoot them with accuracy more easily than heavier calibers. Both these rounds give a much higher penetration and retained velocity at distance than the .243, 6.8 or the .223/5.56mm rounds, which would make them more effective on body armor and more lethal at distance. If we’re not going back to the .308, which in my book is the most effective short-action round, especially in the 168-175 grain range of bullet weight, then the 6.5 Creedmoor or the .260 Remington is the way to go. But if I were Army Ordinance, I’d probably go with the .260 Rem. round, because the only change from 7.62 X 51 is necking down to .264/6.5mm. It would require almost no re-tooling.

  46. I agree with the stupid administrators / politicians. I had a sniper rifle made when the 243 was considered a wildcat round, but I never ran into a situation where it didn’t do what I needed it to do. I have seen the ballistics on the 257 and 270 etc. and while they are good, I don’t know how they would preform for what the military needs. seams in the wars we are fighting now long range one shot is needed more than in the jungles in Vietnam where you have many targets at close range and it is a shoot fast or die situation.

  47. M-14. 20 clip. If you are going light it takes an 8 round striper clip. Can be used full auto. (Think mini BAR)

  48. I would pick the 6.5 Creedmoor round. It’s flat shooting and has gained quite a following. If adopted, then more probably the cost of the round would definitely drop, making it more affordable for the civilian population.

  49. I would take a round such as the 243 winchester, it is flat shooting, low recoil, short cartridge and will punch though just about anything in front of it out to 700+ yards, I would also put a 1:9 twist in the barrel. I could be chambered in the M16 upper / lower with little modification, I can be fitted to just about any other weapon, saw, 700 remington etc. and would span the full range from sniper to crew serv.

    1. I tend to agree with a comprise on a caliber between 6mm to 7mm. Back when they first started using the 5.56, it seemed to me, the only advantage was more capacity in a magazine allowing a soldier to carry more rounds. Idiot administrators always believe they know more than those with feet on the ground. The 257 Roberts or the 250 Savage would also be a decent compromise. The single biggest reason for the 5.56 would be for use in a jungle or other close quarters. One size that fits all isn’t always a good answer.

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