January 26, 2012, 09:57 AM
I have a question for the 1911-experts about a (theoretical!! IŽll never do this until I consider sleeping pills by the tons or jumping off a bridge an interesting option ) experiment:
Lets say we were able to build a frictionless or nearly frictionless 230 gr bullet.
What would happen if we fired this bullet with a standard hardball powder charge?
Please take into account that this bullet would seal the gasses just like a real bullet, so a comparison with shooting an undersized bullet is invalid.
My guess would be serious early unlocking (from lack of forward-pull on the barrel) and a really bad KABOOM.
Guessing right or wrong?
January 26, 2012, 10:29 AM
Probably not because without the frictional resistance incurred by the bullet, the powder charge wouldn't develop peak pressure and accelerating force on the slide. If the powder charge could be adjusted to provide the same pressures, curve/time, and acceleration on the slide...it probably would cause the barrel to link down while pressures were high.
Since there's no way to eliminate the friction with a bullet that seals the bore, we'll never really know. The other option is to do what I did once. Bore the barrel out to .500 ID and fire a hardball equivalent reloaded round.(230 JRN/6grains Unique) The pistol functioned, and the bullet buried up in hard NC clay far enough for it to have been lethal, and I noticed a slight bulge in the brass case just forward of the web.
I measured it with a caliper and compared it to a round that had been fired in another barrel, but I forget what the difference was. It wasn't enough of a bulge to have posed a danger, but it was noticeably bulged. I suppose I could have loaded another round with 7.5 grains, but I'd seen what I needed to see..so I crushed the barrel in a vise to avoid any question of a "Sawed-off shotgun" because .45 ACP shot cartridges are out there somewhere.
January 26, 2012, 10:32 AM
If this is related to that other argument a couple weeks ago...I found something interesting for those who still doubt that the bullet's drag on the barrel has a marked delaying effect on the slide.
Keep in mind that he's preventing any slide movement at the point of peak pressure and maximum force on the slide.
If this had been done with a straight blowback, it'd have broken his thumb.
January 26, 2012, 11:14 AM
It's pretty easy to figure out, there was a thread on it a few weeks ago, the search function is your friend.
Decide just how frictionless your bullet is, that will determine the muzzle velocity.
Compute the length of time the bullet stays in the barrel versus the length of time it takes for the slide/barrel combo of a given mass to move far enough to unlock.
You'll find that no matter what the bullet/barrel friction is, anywhere between zero and infinity, it will have no effect on the timing or functioning of the weapon.
The cleverness of that Browning feller that designed it is amazing, isn't it? He actually had an understanding of the stuff Newton described 400 years or so ago!