How short is to short for 10mm brass? I have some CBC brass that measures .975 to .985 most right around .980. I'm planning on loading a light plinker load in this brass. Biggest issue I see so far is case mouth expanding especially since I'm loading .403 cast bullets.
Short 10mm brass?
- Thread starter Muddydogs
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Ya thanks.
BC17A
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So, I just finished resizing and measuring some once fired 10mm CBC cases and it looks like short is normal, though not right, for Magtech. Most were .980" -.985" and about 20% were between .976" -.979". Other than the flair and crimp, the only other thing I'd be concerned with would be the headspacing causing light primer strikes. I did prime a few of the .976", and .985" cases with Winchester primers and tested them in my Ruger SR1911(no powder or bullet). I made sure they were seated in the chamber tightly against the case mouth and all fired. There was a difference between the firing pin strikes with the shorter cases obviously having a slightly shallower FP hit. I think I'll take out all the short cases and just use them for several reloads to see if and when they'll cause an issue.
sequins
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At least in my Glock 20 headspace is governed by the extractor (it's why I can shoot 40sw in my 10mm Glock with no modifications) so I don't think case length should matter to function, maybe in a revolver where the headspace is based on the case mouth, but not in a Glock or other semi auto where the extractor takes care of that issue.
Those do sound short but it shouldn't really matter much in my opinion, keep it in mind with regards to max loads or high end loads where your case fill might hit 100% early and give you surprise compressed loads (I hate compressed loads and always avoid them, but I love 95-98% case fill loads, so your brass would probably trip me up if I wasn't careful).
Those do sound short but it shouldn't really matter much in my opinion, keep it in mind with regards to max loads or high end loads where your case fill might hit 100% early and give you surprise compressed loads (I hate compressed loads and always avoid them, but I love 95-98% case fill loads, so your brass would probably trip me up if I wasn't careful).
Even in a semi auto pistol and your Glock the cases headspace off the case mouth or at least should. Sure the extractor will take care of short cases but it puts more stress on the extractor. If you do some open minded research about shooting 40's in a 10mm I think you will find that its not the best idea or at least plan on changing out the extractor more often. Reports are all over the place, some people claim they have shot 1000's of rounds of 40 out of the 10mm with no issues and others claim that they had extractor problems within a few 100 rounds.
I am wondering at what case length the case stops headspacing correctly and starts relining on the extractor to do all the work. I'm sure it varies by firearm
but I was hopping someone had a general idea. I'm not sure how one would measure for this?
Like the above poster stated, as long as you maintain your OAL then there will be the same amount of space between the powder and bullet base, you might not be crimping in the crimp groove anymore but the space is the same. Start messing with the OAL to get the case mouth back into the crimp groove could cause issues without a proper load re workup.
greyling22
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I've never been too concerned with case length in a pistol. Esp with light loads. Particularly after I had a couple 380s and 9mm mak sneak in with the 9mm brass and subsequently get loaded on the progressive. They still fired fine. They just looked funny.
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