Posts Tagged ‘technology’

GAil Martin shooting the Dream Catcher recurve bow.

The Loss of a Legend — Gail Martin

Gail Martin — if you have ever shot a bow, it is likely that Gail Martin had a hand in its design. Perhaps directly, more likely at least an influence, but a hand in your equipment’s design nonetheless. Gail was a man who loved archery with such a passion, that he retained an active role in Martin Archery until very recently. Unfortunately, the archery industry lost an icon on July 21, 2013 when Gail passed at the age of 93.

GAU-8 Avenger

GAU-8/A Avenger

Okay, we usually just blog about firearms that you can actually get your hands on. Most people will never get the opportunity to get anywhere near one of these machines, but that doesn’t mean we can’t drool on it. It is what makes the A-10 so damn impressive.

HunterServ

Getting Connected: The NRA on Social Media

In today’s world, social media rules. The quickest and easiest way to get in touch or stay in touch with friends, public figures, or groups that interest you is by following them on any number of social media outlets. Want to know when a group is having an event? Check Facebook. Want to hear what a public figure thinks about a current event? Check Twitter. Want to watch an informative video about a product you just bought? Check YouTube. On the business side of things, more and more customer service actions are handled through social media sites. So, it is important to use these new channels to stay up-to-date in what is happening in the firearm community. The National Rifle Association has a vast presence on social media. The NRA’s multiple accounts fit into any niche you care about. If you are a hunter, but don’t want to hear all about legal mumbo-jumbo, you can follow NRA’s hunting profiles, but not the NRA-ILA. If you’re a woman, you can follow the NRA’s Womens’ Network to get information relevant to you.  And since it’s social media, you make the decisions on what content you get to read and respond to. Here is a list of all of the different NRA groups you can “Like” or “Follow” on Facebook or Twitter.

TactOut Sabre4 flashlight and accessories

A Functional History of Flashlights

By Benjamin Kurata

Since the conception of hand held light back in the late 1890 by Conrad Hubert who developed the first hand torch in 1890 and founded Eveready, humans have looked for better ways not just to see their way through the dark but to also brave the demons of the night. Then, the steady stream of a single beam of light was ok for finding your way but was not satisfactory in a defensive situation.

Bullet Exiting Barell

Interior Ballistics

There are four types of ballistics, interior, exterior, terminal, and forensic. Today we will tackle interior ballistics. Watch my posts over the next few weeks to explore the other ballistic theories. These are very basic principles. Each one is an extensive and fascinating study in physics and math. Please do not let the math and physics scare you. I hope that you will continue to explore these fascinating theories.

Propane running a generator. Courtesy, Eric Peters @ EPautos.com.

Don’t Depend on Just Gas…

Automotive and freedom blogger Eric Peters recently considered the problem of keeping the lights on when the lights go off. At EPautos.com, he wrote, “Having a generator for back-up power is great – unless you don’t have the fuel to run the generator. The irony of the portable back-up generator – most of them, at least – is that they run on gas. And what’s the item that’s usually hard to get when the power’s down? Gas.”

Puma PPS50 drum byBlack Dog Machine keeps each cartirdge separate and not under pressure.

On Reliability of Drum Magazines

Drum magazines have long had a bad reputation. “We found many Angolan and Cuban soldiers dead, with jammed RPK drums in their rifles” said a South African veteran. “PPSh drums had to be down-loaded by a few rounds, usually had to be fitted to individual submachine guns, and jammed more often than box magazines” wrote Soviet veterans of WW2. And yet drums persist in weapons large and small — have you ever wondered why?

The Making of a Gun Designer: Charles St.George

Charles St. George at the range

Charles St. George at the range.

Bushmaster M17 bullpup

Bushmaster M17 bullpup

On the way to SHOT Show last year, I met Charles St.George. I didn’t know who he was, but somehow the Bushmaster M17 came up in conversation and turned out that he was the original designer. It was therefore no surprise that the rifle he displayed at the 2011 show looked like a very brawny M17. The Leader 50, while internally quite different from the M17 used the same basic extruded receiver design as the .223 bullpup. But the internals of the upcoming 50BMG rifle were based on a design of which I had not heard before, the Leader T2.

Charles St.George was born on Malta but moved to England with his parents at a young age. As a child, he had a Colt Peacemaker replica which even came with full-size dummy cases loaded with caps. The gun itself was precision die cast from zinc and Charles played with it until the toy literally fell apart. When his father’s regiment, the First Cheshire, got posted to Libya, Charles tried to replicate the zinc toy in steel. After a month of work with a hacksaw and a file, he had something only slightly resembling the intended form. “The experiment helped build arm muscles, at least!” he joked.

Upon returning to England, he decided to build a .303 semi auto rifle. Scotland Yard sent an Inspector from the Hampshire Constabulary to interview me at home before granting permission. Perhaps having a military father helped. The ammunition had to be kept at the Bisley Rifle Range and used cartridges logged in a register. The rifle he built used a simple tilting lock that locked the breech bolt into the receiver tube. A friend helped machine some of the parts, the rest were fashioned by hand. At the range it would not fire. In retrospect, Charles says that was lucky, for the rifle would have blown up. He knew nothing about metals, heat treatment or the designing of real guns.

As an adult, Charles immigrated to Australia started to tinker again. He built .223 semi auto rifle prototypes until he had a beautiful select-fire weapon with an aluminum receiver somewhat like the AR15 and a non reciprocating charging handle like the L1A1. Long stroke gas system used a piston pinned to a tube which housed the return spring and held to the bolt carrier by a wedge held in place by the cam track in the receiver, a triangular breech bolt and wooden handguards. The design eventually entered production around 1978 as the Leader T2. In use, this gun has particularly mild recoil, especially when compared to an AR15. Forgotten Weapons shows the T2 disassembly process on video.  They also feature photos of a pre-production sample with a wood stock made before the Zytel furniture was ready.

T2 has very mild recoil

T2 has very mild recoil.

Left-hand charging handle does not reciprocate on firing.

Left-hand charging handle does not reciprocate on firing

The Leader T2 production went smoothly because the gun was designed from the start to be extremely efficient. The receiver was based on a 16 gauge steel square tube. Dupont provided the expertise for the Zytel parts, which had not previously been used on an assault rifle. The triangular bolt design (subsequently used on the Serbu rifle, the R4 and Barrett 82A1/M107) simplified the barrel extension and the bolt broaching process. The barrel blanks from Parker Hale were rifled with a simple button rifling machine also designed by Charles. It rifled a barrel blank in about 20 seconds. While T2 resembles an AR180 superficially, it is even simpler inside. All major parts can be removed for cleaning in seconds and stay captive to simplify the take-down. It used common STANAG (M16) magazines.

T2 was shown to represenatives of Italy, Portugal and Oman. About 2000 were eventually exported to the US and a few to Africa. By the time the 1989 and 1994 bans in the US caused the cessation of the production of the T2, Charles St.George had already moved on. His next rifle is familiar to Americans as the Bushmaster M17. We will talk about that design next week.

Silencer Terms and Tech, Part 2

To read Silencer Terms and Tech, Part 1, click here.

Hollywood movies often portray pistol silencers as slightly larger than a toilet paper tube. The high pitched squeak of the shot sounds like a sneaker on a basketball court when the movie star shoots his gun. In reality, most pistol silencers are about as long as the gun to which they are mounted, and sound more like an air hammer or disconnecting the hose from an air compressor. Many centerfire caliber silencers do not even reduce the noise level enough to allow the shooter to safely discard ear protection. Also, a silencer can only affect the noise generated by the muzzle blast of the shot. The gun’s action cycling, the supersonic crack of the bullet traveling through the air (unless using subsonic ammunition), and even the sound of the bullet impacting the target downrange add more sound than most people realize. That’s certainly more sound effects than movie directors can be bothered to include.

Mk22 Mod 0 "Hush Puppy" 9mm

During the Vietnam era, the Navy’s Mk22 Mod 0 “hush puppy” pistol cleverly tackled the problem of slide cycling noise. Starting with a 9mm S&W Model 39, the slide stop lever on the gun was modified so that if the shooter held it down, it would engage the slide notch with the slide still shut. This action lock held the slide closed and turned the pistol into a one shot weapon. By releasing the lever, the slide could be cycled by hand after each shot to rechamber the weapon. This was very effective at making the Mk22 Mod 0 one of the quietest silenced 9mms of its day, but it was awfully hard on the slide stop lever and slide notch, which wore prematurely over the lifespan of the pistol. The Mk22 was called the “hush puppy” to give the impression that it was meant for shooting sentry dogs. Though the Vietnamese rarely used dogs, somehow the hush puppies were heavily utilized by Navy Special Forces anyway.

The wipe design is another piece of silencer tech from the Vietnam era. Instead of baffles, the original Ingram Mac-11 silencer used wipes, which were solid disks made of rubber or felt and separated by washers. The hole in the middle of each wipe was sealed off temporarily by the bullet as it flew through the envelope and physically touched each wipe. In theory this meant that the propellant gas was temporarily trapped behind the bullet and wipe, so the wipe would act as an efficient baffle. In reality it meant a loss of accuracy, melted chunks of wipe flying downrange, and a silencer that performed pretty well during the first magazine and hardly at all by the third one. The gooey mess of destroyed wipes had to be replaced to make the silencer work again.

Replaceable wipes for original M11 silencer

A later development was the integral silencer design, in which the envelope entirely covers up its host barrel. The barrel is ported with many holes corresponding with the positions of the baffles inside the envelope. Each hole in the barrel lets propellant gas escape to be trapped by the baffles. The integrally silenced Mp5SD 9mm submachine gun is legendary for being nearly “Hollywood quiet” when fired. Part of the reason is that the integral suppressor design bleeds off the velocity of the fired round due to all the gas escaping from the thirty (yes, thirty!) barrel ports. The round leaves the gun without breaking the speed of sound, eliminating the supersonic crack of the bullet passing through the air and making the sound of firing even quieter.

The Nielsen Device, or recoil booster, is a relatively new addition to silencer design technology.  In most pistol designs for calibers larger than .380acp, the barrel unlocks the gun’s action by moving rearward and tilting (or rotating, for you Beretta PX4/Cougar fans) inside the slide. In the old days, silencing these pistols caused them to lose reliability for two reasons. First, with the silencer attached the barrel effectively weighs much more than normal. Second, the pressure of the propellant gas hitting the baffles inside the silencer acts like a muzzle brake, pushing the silencer and barrel forward. As a result the action would not unlock correctly and silenced pistols were a nightmare of reliability problems.

The solution to this problem was a muzzle mount and spring assembly built into the expansion chamber area of the silencer, behind the baffles. The barrel is attached to this mount and the rest of the silencer can slide back and forth on it like an old fashioned telescope, with the spring holding everything in place until the pistol is fired.  When shooting, the propellant gases pull the silencer forward like before, but they only pull against the spring pressure instead of the whole barrel. The silencer envelope and baffles slide forward on the muzzle mount while the barrel unlocks the action as normal. The invention of the Nielsen device greatly improved the reliability of silenced pistols and it is now considered a must for shooting a pistol with a tilting or rotating barrel.

Nielsen device removed from the expansion chamber of a pistol silencer

The Nielsen device should not be used on a pistol with a fixed barrel, such as an HK P7, or on a rifle. Since the barrel on these firearms doesn’t move, all of the energy of the recoil booster acts like a slide hammer thumping the silencer forward against its own parts with each shot. Eventually the weakest part will break.

The past 100 years have seen a lot of progress in silencer technology, but Hiram P. Maxim would still easily recognize the grandchildren of his 1909 silencer designs. Although improvements in manufacturing techniques and problem solving additions such as the Nielsen device make today’s silencers far more effective than designs from only a few years ago, the principle of operation has remained the same, and so has the goal—making shooting as quiet as it can be!

The author would like to thank the following companies for their assistance in writing this article:

Advanced Armament Company
2408 Tech Center Parkway Suite 150
Lawrenceville, GA 30043
www.advanced-armament.com

GEMTECH
P.O. Box 140618
Boise, ID 83714-0618
www.gem-tech.com

Silencer Terms and Tech, Part 1

Hiram Percy Maxim, the son of Hiram Stevens Maxim—who invented the Maxim machine gun, is the father of the firearm silencer. An early advertisement for his Maxim Silencer Company explained that the hot propellant gases from discharging the firearm “are made to whirl around inside the Silencer,” and cannot leave the silencer until they have slowed down enough to not produce a loud noise. Although this explanation of silencer operation was first printed more than 100 years ago, it still correctly describes the function of all silencers today. Before the adoption of the National Firearms Act in 1934, Mr. Maxim sold a variety of silencer designs via the US mail, at a price range of $5.00 to $9.50, for those with deep pockets.

Original Maxim ad, click for full size image, courtesy of AAC

“But wait!” some say. “The correct term should be sound suppressor, because it is impossible to make any firearm truly silent.” Even firearms with the most advanced silencers available still make some noise when fired, so the point is well taken. However, the original inventor called his device a “silencer,” and federal and state laws universally call the device a “silencer,” so this article will refer to them as silencers.

Silencers consist of a few basic parts. The envelope is the cylindrical metal tube in which the other components are stuffed. Inside the envelope are the expansion chamber  and baffles. The expansion chamber is a relatively big empty space surrounding the muzzle, and the baffles are like coffee cups stacked on top of each other with a hole drilled through the middle of them for the bullet to pass through. This is where most of the “magic” happens within the silencer. Manufacturers competing against each other for the same exact application, will design very different baffle shapes and sizes. Finally, there is a cap at each end of the envelope, one with threads—or a quick detach adapter—to attach the silencer to the muzzle, the other with a simple hole for the bullet to exit the silencer on its way to the target.

When a bullet is fired, it leaves the muzzle of the gun and passes through the expansion chamber, where the propelling gas behind it expands from the diameter of the bore to fill the envelope. The expansion chamber takes a lot of abuse as it is the first silencer part to get hit by that hot gas. As the bullet continues to pass through the envelope, each baffle catches and diverts more and more of the gas, swirling it around, forcing it to slow down, and converting a lot of its energy into heat—which gets the silencer real hot, real quick. All of this reduces the sound made by the muzzle blast. It is possible to overwhelm a silencer by using sustained full auto fire. If the rate of fire is high enough, the gas from each successive shot stacks up inside the silencer and cannot dissipate into the baffle assembly. The sound of firing will become louder and more muzzle flash will be seen until the long full auto burst ends.

"Overwhelming" a silencer with sustained fire, image courtesy of Oleg Volk

“First round pop” is a problem for silencer manufacturers. Propellant gas from the first shot of a magazine ignites the oxygen in the air inside the silencer, creating extra noise. Follow-up shots fired quickly afterward do not have the same problem because the silencer is filled with propellant gas and air that has already been burned up. When firing stops for awhile and fresh air enters the silencer, first round pop will happen again when firing resumes. A large expansion chamber tends to contribute to a lot of first round pop, but a smaller expansion chamber decreases the overall efficiency of the silencer and can be harder on the silencer’s internal parts. Various manufacturers have different ideas about what compromise is best.

Many pistol caliber silencers are designed to be operated wet, meaning the silencer can be filled with a small amount of water before firing. Upon firing, the water vaporizes, assisting the baffles in slowing and cooling the propellant gases, and minimizing first round pop. A silencer filled with water also takes longer to get hot, since the water efficiently draws heat away from the silencer’s parts. There is no doubt that a pistol caliber silencer filled with water or gel is quieter than a dry silencer— for awhile. Some water is blasted out of the silencer by the pressure from each shot and the rest evaporates quickly from the intense heat, so the wet silencer quickly loses efficiency and subsequent shots get louder and louder. The other problem with running a silencer wet is that if the barrel is tilted up, water will run out the rear of the silencer and down the barrel of the firearm, potentially causing a barrel obstruction. If the barrel is tilted down, the water simply runs out the front of the silencer and the benefit of shooting wet is lost. Some shooters have begun to experiment with filling the silencer with a variety of oil or gel based products which stick to the guts of the silencer and won’t leak out. Silencers being used with centerfire rifle calibers should never be filled with water or gel.

More silencer terms and tech, including the Vietnam-era “hush puppy” and the Nielsen device, are found in part two, coming soon!

X-ray showing competing silencer designs