I can remember exactly: zero. My primary weapon was usually an M16/M4 series weapon like this battered M16A1, and I fired uncountable rounds (sometimes a thousand rounds in a day). And I never needed the forward assist.
True, operating the forward assist is part of some emergency drills, but any time you actually needed it the weapon would be so far gone with fouling that it wouldn’t be safe to fire in the first place. The forward assist is an awkward, prodruding, weight-and-complexity-adding feature, something that just isn’t needed.
Hmmmm. So why is it there?
Simple. The Army insisted. There are plentiful rumors on the internet of how it got added, but Blake Stevens tracked down the real reason and published it many years ago in his book, The Black Rifle. (Publisher site. Amazon link). The internet rumors often refer to a problem with jamming. But before the weapon was even fielded, the Army was demanding that the rifle have some means of positively closing the bolt when it didn’t want to close. There was no problem with jamming, just a desk jockey playing “what if…?”
You see, you could force a 1903 Springfield’s bolt to close on a bulged case, or an M1 Garand, or an M1 Carbine, so, dammit, the new rifle had better let you gorilla-grip it like that, too. (Now, there was no positive bolt-closing mechanism on the M1918A2 BAR either, but ask the guy who carried one in combat what he thought about that weapon. Love is not too strong a word. Apparently, Ordnance officers never spoke to that guy). Gene Stoner fought the Army on this, but the Ordnance colonels who didn’t like his gun anyway wouldn’t give in.
So the Army insisted that the M16 had to have a positive closing mechanism of some kind. Colt hacked and welded an upper receiver, cobbled together a crude improvised forward assist, applied for a patent and showed it to the Army’s experts. They liked it better than simpler designs from Colt and Springfield. Hey… you could now hammer the bolt closed regardless of how bad an idea that might be. So the Army got forward assists (and the Air Force didn’t). For all the actual utility of the forward assist, we might as well be talking about the distinction between Dr Seuss’s Star-Bellied Sneetches and the plain-bellied variety.
The first hint of problems with the rifle in Vietnam came much later: a memo noting complaints of case head separation, on June 25, 1966 (Stevens & Ezell, p. 207). The Army’s insistence on the “bolt closure device” played out three years earlier, during 1963 (ibid., pp. 126-130), and it was finally included in the Colt contract signed November 4, 1963. In later Congressional testimony, the Army’s Harold Yount, one of the Springfield ’03 generation who insisted on it, admitted that testing never did justify it (ibid., p. 136).
So you can pretty much ignore the forward assist. If you’re building a retro-styled AR, you can get uppers without the forward assist; NoDak Spud offers 601/604 and 605 styles. If you’re building a flattop you’re probably stuck with the forward assist.
It’s not only superfluous: the damn thing digs into you when rucking, patrolling, jumping weapons-exposed, etc. etc. It’s one more useless, awkward protuberance added on to a clean, unified design — a nose ring on Sandra Bullock. And it adds small parts and failure modes that didn’t exist before. But don’t take my word for it — the Son Tay Raiders pulled off that historic mission without forward assists at all.
(Image source: (1) what passes for gun collecting in Britain, the Deactivated Gun Collectors Association (2) Army maintenance manual).