The M16A2 was adopted by the Marines in 1983, and then by the Army in 1986. Shortly before its adoption, an Army contract analyzed the M16A2 — and found it all wrong for  the Army.

This is the second of a three part series. In the first part, yesterday on, the Army contractors noted the specific solutions implemented on the A2 and the problems the Marines solved thereby, but complained that the problems and solutions were too USMC-specific. In this part, we’ll discuss just what they thought was wrong about the Marines’ product. In the third part, which we’ll post tomorrow, we’ll list the modifications that they suggested in lieu of or in addition to the A2 mods.

M16A1 (top) and M16A2.

As we recounted in yesterday’s post, the Army let a contract to analyze the Marines’ product-improved M16A1, originally called the M16 PIP (Product Improvement Program but in November 1983, type-classified as the M16A2. Did the A2 meet the Army’s needs for an improved rifle? The contractors recounted 17 improvements in the A2 versus the A1, and traced those improvements back to four or five fundamental goals of the Marine program: more range, accuracy and penetration at that range, more durability, and a burst-fire capability in place of the full-auto setting.

The Army contractors recognized what the USMC had done — and damned it with faint praise.

The M16A2 rifle was developed and tested by the U.S. Marine Corps. The purpose of this present analysis was to evaluate M16A2 rifle features as they relate to U.S. Army training and combat requirements. It was found that the M16A2 did not correct major shortcomings in the MI6Al and that many M16A2 features would be very problematic for the Army. Accordingly, this report provides several suggested rifle modifications which would improve training and combat performance.

The A1 shortcomings that the paper’s authors thought went unameliorated, or were worsened, by the A2 included:

  1. 25 Meter Setting: The M16A2 does not have a sight setting for firing at 25 meters, where zeroing and most practice firing occurs.
  2. Battlesight Zero: The M16A2 does not have a setting for battlesight zero, i.e., 250 meters.
  3. Aperture Size: The M16A2 probably does not have an aperture suitable for the battlesight, e.g., the single aperture used for most marksmanship training, the record fire course, the primary aperture for combat, etc. The 5mm aperture used for 0-200 meters is probably too large and the 1-3/4mm aperture used for 300-800 meters is probably too small.
  4. Sighting System: The M16A2 sighting system is too complex, i.e., elevation is changed three different ways, leaving too much room for soldier error.
  5. Sight Movement: Sight movements on the M16A2 result in changing bullet strike by different amounts; .5, 1, 1.4, and 3 minutes of angle (MOA)*. The sights intended for zeroing, .5 and 1.4 MOA, are not compatible with old Army zero targets or the new targets being fielded.
  6. Zero Recording: The M16A2 does not have a sighting system which allows for easy recording of rifle zero. Also, the zero cannot be confirmed by visual inspection.
  7. Returning to Zero: The M16A2 does not have a reliable procedure for setting an individual’s zero after changing sights for any reason, e.g., using MILES or .22 rimfire adaptors.
  8. Night Sight: The M16A2 does not have a low light level or night sight.
  9. Protective Mask Firing: The M16A2 has not been designed to aid firing while wearing a protective mask.
  10. Range Estimation: The M16A2 sight has not been designed to aid in the estimation of range

Let’s consider those, briefly. Note that every single one of those objections relates to the sights. There are no complaints about the other Marine improvements (not even the hated burst switch). Most of the sight squawks were because the sight was different from the sights of the A1, which were pretty much as Stoner, Sullivan et. al. designed them circa 1959 (the earlier AR-10 sights are different, but the later AR-15 prototypes and their descendants all used something extremely close to the M16 and M16A1 sights. (The USAF/USN M16 and the Army/Marine M16A1 differed only in the absence and presence respectively of a forward assist). Even the protective mask issue is basically a sighting problem — with the then current US M17 gas mask, the rifle had to be held canted to use carrying-handle based rear sights.

Complaints 1-5 relate only to the M16A2 sights, but 6-10 are just as applicable to the then-issued Army M16A1.

Even at the time, it was clear that optical sights were better than irons — scopes for distance and red dots for close-in work. Army special operators had already tested — on the flat range, in the tire house, and on the two-way range — such early red-dots and both-eyes-open sights such as the Single Point and the Armson Occluded Eye Gunsight (OEG). In the early 21st Century, universal optics would end the long run of the M16A2, and sweep away all these problems the 1986 Army contractors worried about. But there was no way to predict that in 1986, not with any certainty.

And that’s Part 2 of our story. Tomorrow, we’ll cover the modifications to the M16 that the authors recommended in place of the A2.


This entry was posted in GunTech, Optics, Rifles and Carbines, The Past is Another Country on by Hognose.

About Hognose

Former Special Forces 11B2S, later 18B, weapons man. (Also served in intelligence and operations jobs in SF).

22 thoughts on “When the Army Resisted the M16A2, Part 2 of 3


Teensy little typo, missing close paren.

M16 PIP (Product Improvement Program*)* but in

John Distai

I read the attached document all the way through. As a Human Factors person interested in firearms, shooting, and organizational effectiveness, it was an interesting read. It was a reminder of another missed opportunity of my youth.

As I got farther into the document and read some of the more “fun” passages, such as where the Army and Marine marksmanship programs were compared, I envisioned the political and professional “beatings” that the authors must have endured. They were (rightfully?) urinating on people’s babies, and such rain showers, in writing, often do not go unnoticed and unpunished. My haloed vision of that job quickly vanished, with the realization that the interesting aspects of that job do not outweigh the political bullshit involved with performing it.


Boat Guy

Obviously THE problem for the Army was that the Marine Corps improved the weapon.

Not Invented Here!


Think of how many trees were saved. I was my battery’s weapons custodian and I would generate countless paper trails to replace A1 handguards after a crack developed because the moon was in its full apogee or something.

Tim, ’80s Mech Guy

I’d like to hear more period stories of training differences between Army and MC during the A2’s development.

In my backwater mech unit a significant amount more time was spent keeping the concrete in the motor pool clean than on shooting skills. At a minimum the TC and driver were going to spend a half hour in the morning and another in the afternoon-any less time would have meant you did not actually DO anything because an NCO needed a half hour to locate Drysweep, E-4 types knew how and where to beg, borrow or steal supplies.

When a qual was coming up vital vehicle maintenance and nose picking time would be devoted to refreshing Joe’s memory on how to actually zero and shoot which ever ’16 the “Armorer/supply guy” handed them on the way to the range.

I firmly believe that an improvement in the sights on the A1 was called for BUT “ease of adjustment” would not have been one of my criteria. If you give Joe something adjustable he will fiddle-fuck with it while sitting in his helmet waiting to wait. Maybe MC discipline and time management practices prevented these problems but my own experience was strictly with Big Army.

Dyspeptic Gunsmith

OK, I’ve got to ask, because I’m just ignorant of the reality. I know the theory. I want to know reality, which, only in theory, is the same.

In my AR’s, almost all the ammo I fire will be XM193 or similar ball ammo – FMJ, 55 grains. I’ve been playing around with handloaded 77gr match pills with some satisfaction. I’ve fired almost no M855 ammo, ever. I think I’ve run two magazines of the green tip stuff through my original AR from the early 90’s, and haven’t used it since. My opinion then was that it didn’t group worth jack. I’ve had a couple customers complain how their AR’s weren’t grouping to their expectations, and upon querying them, found out they were using M855. Asking them to merely switch to XM193 Federal resulted in happy customers.

What was (or is) the point of the M855 ammo? Sure, it’s seven grains heavier. Does the steel core actually amount to anything?

Hognose Post author

Yep, penetration at range. At 800 yards, M193 pings off a WWII-style steel helmet. 885 goes through. 885A1 is superior all round but AFAIK is not going to be publicly available.

Tim, ’80s Mech Guy

Small batches of 855a1 are showing up around here as collectibles at $5 a round. I’ll pass on maybe effing up my barrel extension or upper with those even if they hit the market under fiddy cent.


More to the point, while M-855 is more accurate, and penetrates more at range, including steel pots, practical experience from the sandbox noted that M855 torso hits tended to leave small neat holes in Hadji, followed by him scampering off to be patched up and fight again another day; whereas DMs and snipers using the M-16 platform reported anecdotally that torso hits with 77gr (Black Hills) ammo tended to leave Hadji’s carcass DRT, until the sun came up next morning, not just for counting coup, but for subsequent intel exploitation.

In a practical sense, news you can use.

Steve M.

The same issue was discovered earlier in Somalia. 855A1 is supposed to do something to cause a larger wound cavity immediately after penetration, unlike the neat pin pricks of the old 855.

Cap’n Mike

My understanding is that the steel penetrator is responsible for the accuracy problems associated with M855.

The more components involved in the bullet, the more chances of inconsistencies from round to round.

Steve M.

That was my understanding too.

Tim, ’80s Mech Guy

Uncle’s specs call for 4 moa accuracy out of 855, IIRC, so I have never expected anything from it. Most milspec barrels I’ve shot were capable of way better than that but those were new or at least fairly new barrels that hadn’t been subjected to the kind of abuse that GI guns might well have seen. Other than some 64gn Razorbacks that I keep for hunting season I’ve gone to shooting 193 spec or 55gn equivalent stuff. I plan on using 7.62 if shooting past 300y/m. I think 193 is superior to 855 inside that range for non game deer sized targets. I had pretty good results back twenty years ago on actual deer with 69gn Match Kings, there was really not much of a selection of deer bullets then. The 64gn Power Point was basically it if you were wanting to shoot deer with a 5.56 and I figured heavier was better so I had a local custom loader do me up some Match Kings. At the ranges I was shooting deer though I think 193 would have done fine but regs specifies non fmj assuming that that means expanding.

I’ve also heard rumors about 855 having a bunch of variations in the ratio of steel to lead from contractor to contractor which would make sense if you are trying to maximize profit on a multiple million round contract that only has to meet that 4moa requirement.

Swamp Fox

According to the US Army studies the heavier barrel is the wrong profile.

DTIC has a barrel temperature study on the A1, coolest during firing is the chamber, next coolest under front sight post, highest 3 to 4 inches in front of bolt face when bolt is locked in battery.

Tim, ’80s Mech Guy

Slight tangent but has anyone seen that new zero target over on Soldier Systems? Looks like it might be an improvement-minus the Grossmanesque statement in the explanation.

Dyspeptic Gunsmith

Thanks for the explanation on M855 gents.

I’ve always wondered if anyone fielded a round with a tungsten penetrator?


It’d probably be too pricey.

Steve M.

I think it was considered, but as Aesop said, price was a factor. Maybe it was bismuth. I thought I read something in a gun rag about the development of 855A1 and the various designs considered/tested. I think it was one of the NRA’s magazines.

the M995 was a true AP round.

M855 is slightly more accurate at longer ranges than M193. Despite the word of countless internet marksman, M193 is the less accurate round.

As anything there are piss poor lots of M855 and exceptional lots of M855. I have shot some pretty impressive groups with M855 with good lots that exceed spec.

I have even demonstrated hitting a man sized target at 1000 yards with an A2 and M855 as well as an M4. That doesn’t happen with M193. Not that either is practical.

If people are complaining to you that M885 is not grouping as good as M193 at the range, its more likely they have some mental thing making them believe there is some big difference. Basically they would perform about the same on a range the layman shoots at.

MK262 ( 77gr) ammo is superior to all over military rounds for accuracy and long range. The new ballistic tipped 77 grain match kings will even give the true terminal performance that the older “open tipped match” round of the military Mk262 would not always deliver,

there is no reason for some one at the current time, who is serious about wanting accuracy , range and terminal performance out of there AR15, to be using M193 or M855 for anything other than general plinking and training. There are too many excellent rounds on the market now , for anyone to be seriously trying to decide on using M193 or M855 in the few mags they keep for home defense, the back 40 or LE duty, or anything that needs accuracy and terminal performance, As little as 17 bucks will not buy 20 rounds of MK262 type ammo for use as a home defense mag.

Hognose Post author

The Mk318 is occasionally available. I have not seen M855A1 available anywhere, but someone has the bullets on GB. Pretty spendy.