The Colt M4A1 Rifle — An Old Friend

Black Colt M4A1, barrel to the right on a white background

There are many renditions of the popular AR-15 rifle. Some are parts guns put together on a workbench; others are well manufactured using a modern process. The Colt AR-15 has seen wide police and military use and remains the rifle with the greatest service record. Some decades ago, I kept a Colt HBAR in the police cruiser, carefully maintained the rifle, and never had cause to replace it. The Colt challenged me to be all I could be and I enjoyed firing the rifle.

Today, I most often deploy a shorter carbine version of the AR-15. Among my favorites is the rifle covered in this report, the Colt M4A1. It is a personal rifle, not a loaner, and that means I have tested it until I trust it and it is good enough to ride with.


Colt’s M4A1 is a civilian version of the SOCOM carbine. The primary difference is there is no fully-automatic option, which is fine with most of us. The rifle is immensely appealing to Colt fans and to anyone in need of a reliable, accurate and effective AR-15 rifle. It comes well-appointed with excellent battle sights, a modern forend with plenty of rail space and excellent ergonomics. The new rail design is supposed to help dissipate heat more efficiently.

Black Colt M4A1, barrel to the right on a white background
The Colt is more than a basic AR-15, it is a professional-grade rifle.

While I did not test the rifle to the extent the military has, I was able to fire my semi-automatic rifle until it smoked like an old Ford in need of a ring job. The rifle is set up with the modern adjustable stock, post front sight, and a remarkably easy-to-use rear sight. Rather than rotating a wheel for range adjustment, the rear sight is click-adjustable for yardage.

  • The rifle features a modern forend with quick detach sling attachments as well as the standard rail for use with lasers and lights. The rails accommodate anything from an under-the-barrel light to a modern red dot above the barrel. The slots are numbered. This allows a degree of confidence in the zero when returning a tool to the rail.
  • When handling the rifle, the four-position stock allows a wide range of adjustment for each shooter. The barrel is chrome lined. The bolt, carrier, ejection port and other parts are familiar to AR-15 shooters, and the rifle is well made of good material.
  • The trigger and hammer pins are .0154-inch for reference. The bolt is well finished, and the gas keys are properly staked. Why some makers still refuse to properly stake gas keys is beyond me, perhaps for the same reason they do not chrome line the barrel: They are getting by as cheaply as possible.
  • The chrome-lined barrel features a 1:7-inch barrel twist. This is optimum for the present 62-grain Green Tip service load. However, the rifle is accurate with loads from 55 to 77 grains. The barrel begins at .640-inch and it is .0750 inches in diameter at the gas block.
  • The sights are the usual front post and rear aperture, however, the rear sight features a single aperture and a drum that may be rolled for adjustment for the service load to well past 500 yards.
Colt M4A1 quality control
Colt quality control is excellent in this rifle.

The rifle is all AR-15 and anyone familiar with the type will be able to get the measure of the Colt in good order, as far as handling, loading, firing and maintaining the rifle. The advantage is in quality of manufacture, and to some of us, the Colt name means a great deal.

An advantage of this rifle over most AR-15 rifles is that the safety lever is ambidextrous. As a result, it isn’t difficult for left-handed shooters to manipulate the magazine release with their forefinger although the safety is more difficult to engage. The Colt M4A1 neatly solves the problem of left-handed use.


When firing the carbine, I was careful to use the hand-forward grip that makes the AR-15 so fast and effective. I used primarily Winchester 55-grain FMJ loads in the initial evaluation, as well as the Magpul PMAG. I used both the Gen2 and the Gen3 Magpul magazines, as well as the Gen3 with cartridge counter window and over-travel insertion stop. All functioned ideally. The magazines never gave cause for any concern, locked in as designed, and fell away when the magazine release was pressed.

By keeping the hand close to the muzzle, the rifle is controlled in rapid movement. While the rifle is more stable with this hold, the real advantage is in speed and rapid movement. The Colt showed its heritable nature, giving excellent results in rapid-fire at man-sized targets at 25, 50 and 100 yards. Minute-of-angle work wasn’t attempted at that time, and I fired the rifle until the forend smoked—literally smoked—and the barrel was pretty hot.

Black Colt M4A1 focused on the sights
The Colt sports an excellent set of battle sights.

The Colt sights were delivered sighted high, so some Kentucky elevation was involved. Once the sights were reset, things went smoothly. The Winchester USA ball ammunition was expended without a single stutter.

After a cleaning session, and lubricating the rifle, the first 300 rounds showed no signs of eccentric wear. The next session was slower paced, with time taken to properly sight the rifle. Frankly, it was so much fun to fire such a great rifle I had made a dent in my .223 reserves! I was lucky enough to have obtained a quantity of Federal American Eagle 62-grain Green Tip. This is the present service load. The 62-grain full offers greater penetration than the original 55-grain FMJ load and offers excellent accuracy at longer range.

The rifle gets better the more it is fired and in short, order had digested 150 rounds of this loading. Since I was using iron sights, the shooter was an important part of the equation, and the Colt features a general-purpose trigger not a target-grade trigger. It is controllable under all conditions and doesn’t limit a skilled shooter (at least at 100 yards). The rifle seems to be capable of 2 MOA or better.

The American Eagle loading is well worth the time and effort to obtain and keep in the ready bag in quality magazines. The Colt is accurate enough to demand good optics, and perhaps it will wear something in that line sooner than later.

This rifle is more than accurate enough for varmints and pests at moderate range. Deer-sized game is not out of the question with the appropriate loading. I wished to test at least one jacketed soft point loading. The Hornady .223 55-grain JSP (Hornady #80256) was tested. Function was good and accuracy consistent with the reputation. I also sacrificed a few rounds from my Zombie shooting stash. The Z Max 55-grain load proved accurate, reliable and a ball of fun.

In short, the Colt is a professional-grade rifle well worth its price. Accurate, reliable and wearing a proud name, the Colt is a top AR-15 that will serve your needs well.

Colt M4A1 
Manufacturer Colt Defense LLC
Action Gas-operated, semi-automatic
Barrel Length 16-inch chrome-moly, chrome lined
Receiver Forged 7075-T6 aluminum
Barrel Length 16-inch chrome-moly, chrome lined
Caliber 5.56×45 mm NATO (.223 Rem.)
Weight Unloaded  7 lbs., 1 oz
Sights Adjustable front post; rear sight adjustable for windage and elevation
Stock or Grip Adjustable
Capacity round capacity
Magazine  20- or 30-round box
Rifling Six-groove, 1:7″ right-hand twist
Trigger Single-stage, 7-lb., 6-oz. pull

When are you planning to give the Colt M4A1 a try? Or have you already taken it to the range? Tell us all about in the comment section.

About the Author:

Wilburn Roberts

When Wilburn Roberts was a young peace officer, he adopted his present pen name at the suggestion of his chief, as some of the brass was leery of what he might write. This was also adopted out of respect for families of both victims and criminals. The pen name is the same and the man remains an outspoken proponent of using enough gun for the job.

He has been on the hit list of a well-known hate group, traveled in a dozen countries and written on many subjects, including investigating hate crimes and adopting the patrol carbine. He graduated second in his class with a degree in Police Science. It took him 20 years to work himself from Lieutenant to Sergeant and he calls it as he sees it.
The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (24)

  1. I have the exact same rifle. It’s a Colt LE6920 SOCOM. Unfortunately the quality control in cosmetics with my rifle has gone down hill. My lower receiver is in excellent condition when it comes to cosmetics. However my Upper Receiver Assembly has very poor Cosmetic Quality Control. What I mean by that is I have found several dings, dents, divots, and pitting in the metal itself particularly the Aluminum Upper Receiver and the A2 Front Sight Base on the Front Sight Post Ear Protectors. Also the markings stamped on my barrel and bolt are not easily readable and look poor. I sure wish that Colt will help me solve and fix this problem for me. If not then does anybody have any suggestions on what I should do? Thanks.

    1. My new Colt M4A1 SOCOM also came with poor quality control on the finish. It looks like many of the assemble operations that were done were dinged by the assembler and or the tools used since the damage is mostly near the pins and stake areas. The lower receiver looks to be scratched prior to the anodizing operation. I really like the rifle and Colt has responded by sending me a shipper for INSPECTION, not a commitment to refinish. I will most likely pay to have it properly finished by another company.

  2. Yes, it is an ambi safety. Only a few companies seam to make them. Their around $30~$35. Check YouTube be careful with the spring and detent.

    1. I can’t remember if I got mine from either Misway, CTD, or somebody off Amazon. Check the MaTech website for dealers.

  3. Good, yes, but they are heavier than many other quality BUIS, and take up too much rail space for good size & weight constraints. Then again, if you have a different philosophy of use, they may serve your purposes well. I personally think Colt could’ve done better.

  4. It isn’t a “SOCOM” rendering if it is only .640 – inch under the handguard. Please check your references.

  5. Essentially the Colt Defense LLC., M4A1 5.56x45Nato Carbine, is a ‘piece of crap”. Since 2007, Colt Defense LLC., has lost every Defense Contract Competition because it can’t even pass the minimum “standards” under US. Military’s set guidelines.

    1. I own four of those so-called pieces of crap Colt M-4’s you are referring to, all in different configurations. I also own a full sized Colt AR15A4. I do not know from where you have obtained first hand information, but being an owner of these might give me an edge. That is, I actaully have them to fire. I have had no problems with any of them. They are superbly manufactured to the most stringent standards and I would place my life in their hands. In fact, I am retired from a military combat career field and did trust my life (and that of my Comrades) for well over 20 years…and they were Colt’s. I also have a Bushmaster Patrolman A3 and it too is a reliable platform worthy of respect. Might I then inquire, respectfully, what AR15 platform you personally own?

    2. Ignore that Secundius character… he made a complete fool of himself over at the CTD article about “AR rates of twist”. Colt makes a fine AR – better than many or most, I’d dare say. I’m thinking of adding one to my larder… in fact, this particular model as shown would be all or more than most folks would ever need in an AR platform.

    3. I have to disagree. I have the LE6920MP-B and I love it. Very well balanced and sooth operating. Colt has served our great nation well and I own one of their AR15(s) with great pride. I’m very thankful they are still American-made. Although I own other AR(s) of different manufacture, I feel I got every penny the rifle I purchased when I bought my Colt.

    4. GRA – I am a 60 year old man, with eyesight accordingly rated (not blind, but not 20/20 either), and apart from the rear sights on this M4, I don’t exactly see any difference between it and the LE6920MP-B, which I also have (great buy, I also am totally satisfied with it!). Ok, so it might not have the ambidexterous safety, but for those two things, is there really any difference with these two rifles? I see 16″ barrel, chrome moly, 1:7 rifle twist, forward assist, 30 rd. Magpul PMAG, the same butt-stock, the forend does have that SOCOM look, where the LE6920 of mine came with the vertical grip, but apart from those very minor things, I feel like I’m looking at essentially the same rifle. Comment?

    5. I think we may have misunderstood each other. I have no problems with the SOCOM. The only reason I dont have the SOCOM is because it was never on sale when I was buying the LE6920MP-B.

  6. A nice rifle and an excellent BUIS. I think I’ll replace the MAGPUL on the 18″ mid-length that I put together with the MaTech.

    1. I bought the MaTech sights and they work great. I think the sight picture is a little easier to acquire with this rear sight especially when shooting with both eyes open. At least it is for me with 53 year-old vision.

  7. Why do you know include MSRP for all of the firearms you test, review, anaylize on The Shooters Log ? Sure would save us readers a lot of time and effort. I know the MRSP is readily available to you so why not include it?

  8. I’m confused over the differences between the “twist” in the barrels being offered by the various AR manufacturers. Specifically, my Mossberg MMR has a 1:9 twist in it’s 16.25″ bbl instead of the 1:7 twist referred to as “optimum” for the 62 grain .223 rounds in this article. So what grain bullet(s) is/are considered as the best for this1:9 twist? What effects will manifest themselves in shooting various weight rounds in my MMR?

Your email address will not be published. Required fields are marked *

Your discussions, feedback and comments are welcome here as long as they are relevant and insightful. Please be respectful of others. We reserve the right to edit as appropriate, delete profane, harassing, abusive and spam comments or posts, and block repeat offenders. All comments are held for moderation and will appear after approval.

Discover more from The Shooter's Log

Subscribe now to keep reading and get access to the full archive.

Continue reading