![]() i would suspect, though can't say definitively, that load selection (powder, primer, bullet) will have a much larger impact on accuracy than brass length. but how much of a difference in length is required to make a perceptible change in accuracy is uncertain, though maybe somebody out there has an answer. That said, if you're trying to squeeze the max of accuracy from your pistol then maybe case length is an issue. a few thousandths here and there doesn't matter for most guns (probably 99.99% of them). it is probably generally the case that brass fired in semi-automatic pistols does not change length significantly in either direction over it's useful lifetime to present a problem for the majority of users. i can't recall seeing any posts that someone had said that's happened to them because of brass length issues, though it may have happened and either they didn't report it or interpreted as a different kind of failure or whatever. this will depend on the length of the brass, the chamber dimensions, and the fit of the barrel. brass that is too long could prevent the slide from going all the way forward = out of battery. tiny differences as you've noted won't make a significant difference in the type of accuracy that is required for that type of shooting.īrass that is too short, and i mean waaay too short, will slip a little farther into the chamber to the point where the extractor grabs it and prevents it from slipping any farther. the typical IPSC shooter, which probably describes a majority of the folks on this forum, is less concerned about getting the utmost accuracy from their ammo since their targets are large, close and they're shooting fast. the most import is whether it functions in your gun. with the 0.125 pocket depth of bolt face, this will leave a rough 0.010" gap between bolt and barrel face, and still sammich them longer cases just fine and dandy.Part of the answer comes down to practical issues. IF you buy a 9mm AR-15 barrel, you want 0.135" case sticking out end of barrel using a 0.744" sized case. I need to take another 38 Super Comp case and cut it to 0.754 and see if my GLOCK will close on it. chambering a 744 case in a 754 hole aint going to work real well. Somebody need to sit down and get their act together and revise the so call chamber numbers / max case length to more realistc values. had to set back my Uzi barrels too, and I had friend cut a barrel for M11/9 and set 'space to my spec. both barrels had to be set back to run with 0.744 case used as a gauge to set up headspace to where bolt face would hold cartridge between bolt face and case mouth. I have had 1 barrel made, fell chambered it deep, fire pin not hit primer. common measure is 0.743 to 0.748" on most common case found. ![]() Just curious if any of the reloading gurus around here have an idea why a specification was established but brass, at least referring to 9mm, is routinely well below minimum.īeen in the 9x19 business for 28yr. I didn't spend a lot of time with the calipers but found everything I checked 0.745" or less and even down to 0.736 or so. I also have never trimmed pistol brass and certainly do not plan to trim unless necessary for my reloads for this particular rifle. The headspace on this rifle sits at 0.747" overall (chamber & bolt face recess) or just 0.003" beyond case minimum length So, I started digging through my piles of brass to see if I found anything greater than 0.747". ![]() I was initially concerned that I would run across rounds, either commercial or reloaded, that would not chamber properly. My recent curiosity is brought about by a new 9mm carbine barrel that arrived with a substantially short chamber. As well, I have never purchased new brass. can't say I ever pulled a new commercial round to check.
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