I’ve read that in line stocks were developed as part of the quest to make automatic rifles controllable. For example the FG42 the M16. The reasoning is that because the recoil and shoulder rest are in line, that you don’t see muzzle rise the way you do when the recoil is not lined up with the stock which bends for comfort in using the sights.
Sounds reasonable to me. The problem I have with this is that every picture I see of a guy firing an M-16 shows only the bottom inch or so in contact with his shoulder.
The rest of the buttstock is touching air above his shoulder. It seems then that this idea has failed and the M-16 stock needs a redesign. Am I missing something?
My brother told me that the M-16 has part of its action in the stock. I can understand wanting to move the action behind the trigger to decrease the overall length while still having a reasonalby long barrel. I think this diagram of the mount version shows how far back the action goes. There is still space to have the butt of the stock lower so it acutally lines up with the shoulder. Some hunting rifles have a stock like that. The more of the butt that is in contact with the shoulder the easier it is on the shoulder. And if a square inch is fine, get rid of the rest of the butt to save weight.
Another way to fix this error is to put your sights above the barrel. The M-16 already does this, but not enough. Instead of 2 inches above it needs about six inches. According to this chart the bullet travels about 16 inches vertically as it travels within its effective range. Thus sights six inches above the barrel would still be able to instersect most of the flight path. Still, its better to have sights close to the barrel, and fewer things projecting from the rifle to get snagged on things. Its not as if the other projections like the magazine or the pistol grip can go under the now elevated sight.
Another solution is to put the barrel in front of the trigger. This has too many complications to be worth it.