What do I trim new 45-90 brass to

358Scout

358Scout

Regular
Rating - 100%
72   0   0
Location
Saskatoon
Chamber cast my 45-90 Shiloh Sharps - right on at 2.403"
I have new Norma 45 caliber brass needing to be trimmed and sized.
Do I trim it to 2.403 before a full length sizing or longer. If longer - how long?

I'm asking because I need to know if the case will shrink or compress on the first full length sizing.

I after the first firing I will only be neck size these cases.
 
New .45-90 brass cases which should measure 2.4” But new from factory actually measure from 2.389” to 2.393” in length before fire forming.
Don't go over 2.4 because just a little case length growth and you'll have pressure issues. my 2 cents
 
Last edited:
Unless they are much longer than 2.4" I'd shoot them (you are using black powder I assume?) and then measure and trim if required. They should get a bit shorter but I've found that my Shiloh chambers are tight enough that there isn't much change in length. Truth be told I've never trimmed any .45-90 brass when new as it's always been a little shorter than the chamber.

The main issue I have had with my Starline .45-90 brass is that the rims are not uniformly thick. Not just from piece to piece, but variations in rim thickness on the same piece of brass.

Chris.
 
The maximum case length for the 45-90 W.C.F. is 2.405 inches. This is from a Winchester drawing dated Feb. 16, 1912 and reproduced in the book "The Winchester Lever Legacy" by Clyde Williamson.
 
Ah, that's good. The Norma .45 brass is good stuff. I use it in my 45-110's. You may find that the mouth thickness is a bit much for shooting grease grooved bullets depending on your chamber. I can't chamber grove diameter bullets in my .45-110 Shiloh when using that brass bu it suits me fine as I only use bore diameter paper patched bullets in that rifle.

If I were you I'd do this... It's a bit of a PITA but you only need to do it once. I'd take the brass and cut it down to just over 2.40". For this I've used trim dies ( or even a Dremel but that is rather tedious) . Then I'd size it with your die backed off 5 or so turns, and see if it will chamber. Keep turning the die down until it will chamber. At that point you've sized it as little as possible. Then trim it down to the length you got from your chamber cast.

That procedure is slow and painful but the brass should only shrink a few thousands by the time it's fireformed. It may take a few loadings to get them fully fireformed when using BP.

That's what I do, but I'm picky :).

Chris.
 
You must log in or register to reply here.
Back
Top Bottom