Way back in the day the M16 was foisted on the Army. Through a number of upgrades, chrome lining the chamber and bore and the addition of the forward assist, we got the M16A1. For my European readers, the abbreviation “gr” means “grains” and not “grams.”
Now the M16 and M16A1 fired the completely adequate at 300 meters or less 55gr M193 cartridge. Perfectly fine for the jungles of Vietnam or going house to house in urban combat, but across the wide open plains of Poland or Ukraine something must be better! So the enterprising Europeans came up with the SS109 62gr bullet, gilding metal jacket, steel penetrator tip, and a lead slug behind. A 1:9 twist would stabilize the 62gr bullet just fine, but the longer tracer rounds designed for use with the SS109 bullet required a 1:7 twist.
And since the 1:12 twist of the M16A1 was inadequate for the new ammunition, the USMC took the lead and gave the US Military forces the improved M16A2! With an upgraded rear sight, 3 round burst trigger (Boo!) and heavier barrel forward of the handguards (the Army was too cheap to rework the M203 grenade launchers to work with a different profile barrel). But once again, the Army was forced by another service to adopt a standard issue rifle. Kudos to the USMC for specifying a better rifle than the US Air Force.
The M16A2 remained the US Army and USMC rifle of choice up until 1990 for the Army. The introduction of the M4 Carbine, essentially an the exact same lower receiver and trigger as the M16A2, but with a shorter butt tube and stock, shorter barrel and gas system, and an all new upper receiver with a detachable carry handle. The M4 was a hit with people who had to carry rifles a lot, and even with the shorter barrel it still out performed the original M16 and M16A1 in terms of putting lethal fire at distances beyond 300 meters.
The M4 was the first rifle in the M16 saga that was actually an Army led procurement. The USMC didn’t abandon the M16A2 and M16A4 (an M16A2 barrel on an M4 upper receiver and A2 lower group) until 2015. Yes the Army had the M4 in the inventory for 25 years prior to that as a standard issue weapon, but Marines will be Marines. Now the M4 of today is not the same as the original M4. There have been at least 92 separate upgrades to the M4 and the US Army acquired the “Technical Data Package” (TDP) for the M4 in 2009, which coincides with the much discussed and argued over Individual Carbine Competition.
Some have said that the Army is so wedded to the M4 that it would sabotage any efforts to replace the iconic Stoner derivative. The evidence doesn’t support that conclusion, but people would rather believe in unprovable conspiracy theories than accept that the Army had been screwed over the coals so badly by the USAF and the USMC followed by Colt with the worst procurement contract until the coming of the Stryker family of vehicles (the Army STILL doesn’t have the TDP to do its own work order modifications without GDLS say so, which is pretty criminal in my opinion) that after the 6 best industry carbines submitted for evaluation didn’t prove substantially better than the M4 the Army just said, “screw it, the budget isn’t unlimited so we’ll stick with the M4 for now.”
The conspiracy theories about how the Army was unfair to their favorite rifle abound. My favorite is the switch from M855 to M855A1 during the testing period was unfair because M855A1 was optimized for the M4 gas system. I could care less.
Another is that the reliability standards were set impossibly high. I say that when a modern Army M4 is pushing 260% of the original specified M4 reliability (1,600 rounds mean rounds fired between failures) that expecting a replacement for the M4 to be twice as reliable isn’t unsound. When replacing half a million or so rifles, at the cost of over 2 Billion dollars, you want something substantially better, not something sort of better kind of maybe. A combat load is 210 rounds, so the difference between 1,600 and 1,800 mean rounds between failures is meaningless from the end user perspective. An armchair general can say, “200 more rounds between failures!” and claim the Army is killing off future American boys and girls because it won’t adopt the newer system that is only marginally better in a test environment almost in the same breath that they say the F-35 can never replace the glorious A-10. How they can admit that newer doesn’t always make sense when it comes to planes but not rifles is beyond me.
Now the M16A1 tipped the scales at 6.5 pounds. The M4A1 while being shorter and handier, is 6.75 lbs roughly. The centers of balance are different and the new M4A1 goes back to a full auto trigger (yay for only having to deal with ONE trigger pull instead of three!) with a heavier barrel for better heat mitigation.
It isn’t perfect. But the Army now owns the TDP so it can play with the configuration all it wants. The USMC can do the same.
But, anyone who feels bad that the H&K416 or the FN SCAR weren’t selected, just be happy that the USMC adopted the M27 based on the H&K416, and the FN SCAR has seen some limited use in SOCOM units. So someone out there is buying a few of the toys, and putting them where they think they might be value added.
I’m sure out there is a crusty retired Master Sergeant who learned marksmanship on a Rifle, M1 (called the Garand by us youngsters) who remain convinced that it is the man, not the weapon, that is the most important system on the battlefield. The toys don’t win the fight, at best they help.