Originally Posted by
Markasaurus
now THAT looks like the ultimate AR bolt, indeed! At first glance the third hole in the bolt carrier would seem unnecessary...but simply imagining the massive pressure the whole BCG is subjected to upon firing, another bleed hole cannot be a bad idea at all. One has to ask oneself why Eugene Stoner in his infinite wisdom did not think of such design tricks to begin with, but remembering two things about the entire AR platform could easily explain it all! 1 - Stoner was first and foremost NOT a small arms designer! His engineering background was in lightweight alloys and composites for AEROSPACE not guns after all, the difference between them could be thought of as that between chalk and cheese...and secondly, the AR 15 was a very hurried redesign of his superb AR 10, a much larger weapon with bigger receiver, barrel, chamber and BCG (notice all the photos of the earliest AR 10s, intended for competition in the US Army contest to replace the M1 Garand, had CHROME PLATED bolts and bolt carriers - indicating Stoner realized fouling was going to he a big problem). In other words, sub-par material strength for the carrier and especially the bolt, was guaranteed to be built in when the large BCG of the AR 10 was simply made smaller for the 5.56 round!
Being a complete AR noob that i am, i have never had a bolt fail. I suspect that many bolt failures occur in soldier weapons that get fired full auto quite a bit, the devastating combination of heat, dirt, and pressure surely plays hell on the bolt of any M16 or AR. That's a no brainer...
on aCould the AR USE a stronger redesigned bolt to fix it's flaws, certainly! Are most makers of AR rifles going to adapt the more expensive but stronger bolts, and are users going to retrofit? The short answer is almost certainly NO. THE current bolt works well enough that most people will see no need if it costs them anything..i have already solved this problem, answer, carry a spare bolt? It fits right in the hand guard after all...and i understand a lot of soldiers in afghan do just that...some even carry a spare BCG, and why not?
I think if you want to make the ultimate bolt, you are not dealing really with the metallurgy of steel. The 15,000 round bolt life quoted above seems as much ass it's possible to get from steel. And you are limited by the shape the bolt must be just to fit and function. For a really improved bolt, i think you are really going to be dealing with titanium, titanium alloy or some other exotic metals since the design limits of carbon steel in an AR bolt have probably been reached long ago.
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