Shiloh Rifle Forums

I've got brass that measures, 2.850". Shooting a 45/70 Shiloh Sharps, would that be considered too short using 68 grs.? The brass seems to be getting shorter the more I shoot. Not longer.

Sounds pretty long to me, waaaay too long for a 45-70. I presume you mean 2.050?

Sorry.
2.085 was what I meant.

Does it shoot great? If so, who cares. I've got brass that goes from 2.090 to 2.10. Mixed and shot and I can't see any difference. Shoot it and see how it works in your chamber. If it doesn't, sell it to someone shooting a 45-60 WCF. H will have to cut it back anyway.

Woody.

could always re-size and load it up with a good charge of 5744 to stretch it out a bit.

My 45-70 brass does the same thing and I have never heard a good explanation why. Brass is supposed to lengthen not shorten. I've even nibbed short cases out to 2.130 and they start to shorten again but not as fast as the first time, I don't resize them either.

mdeland wrote: ↑Sun Jun 20, 2021 1:55 pm My 45-70 brass does the same thing and I have never heard a good explanation why. Brass is supposed to lengthen not shorten. I've even nibbed short cases out to 2.130 and they start to shorten again but not as fast as the first time, I don't resize them either.

its from the mouth peening you never get !!!

I had a problem using Hornady dies. When resizing I was coming up short. Someone on here suggested trying a different sizing die and when I resized the same brass with a RCBS die it came out longer. No more Hornady !

That's true, I never have had peen-ed case mouths but I don't think that you really believe that is the reason for the shortening cases.
I have wondered if the shortening cases is from using a SAAMI spec chamber reamer which is not close tolerance match as some custom chambers are.
I hope to find an answer to the question one day.

Yup, the tighter the die, the longer the case will be after resizing. At least gives you an illusion of length, nothing more. After all, when you fire, the case will expand again and shorten, most of it before the bullet is starting to move.
And it only grows longer on sizing because you're squeezing the case, the material has to go somewhere. So I'd say that RCBS die is probably 'oversizing' the case.

One more thing I'll add. Out of the 100 cases all fired the same amount of time, 32 shortened up, while the rest remained the same length. More confused than ever. Thanks for all the opinions.

Gary

Well, let's see now, if you leave the chamber wet after wiping it has been said your brass will stretch, Hmmmmmmmmm. If you have oil on your brass it will stretch, Hmmmmmmmmm. You could buy one of the case stretchers, my 45-70 case stretcher worked great, I never could the 40-65 stretcher to work.