Norma brass

R

rklapp

New member
I've been using a mix of PPU and WIN brass for my 91/30 MN (7.62x54r). I haven't detected any accuracy issues between the two. I know the WIN is noticeably heavier than the PPU. I usually have to trim the PPU more than the WIN. After six reloads, the PPU is starting to wear out, so I bought a 25 box of Norma brass. The Graf website says it's 54r but the box when it arrived says 53r. The measured difference is about 0.4 mm. I don't imagine I'll ever have to trim the Norma brass.

In my experience, the length of the case affects the consistency of the bullet. I should either replace all my brass with Norma or return the box. If I test the brass, then I can't return it. What difference would I expect between brass that is 0.4 mm apart? TIA
 
I'd use it..

I've found different sources that claim 7.62x54R, and 7.62x53R. They are essentially the same casing, just depends where it's made.
 
Norma probably uses the 53R since that's what the Finn's called this cartridge. I'm not a Mosin shooter, but I believe many Finn rifles were bored for .308" diameter bullets, too...not certain. FWIW, some Sako ammo I had used a .308" diameter bullet.
You get the same variations with 7.65x54, or is it 7.65x53?
Unless you're concerned about crimp groove/cannelure alignment or factory crimp contact, the 1 mm difference should not be an issue.
I'd use it and get shooting.
 
I read somewhere that going 1 mm shorter will affect accuracy. What are your thoughts?
 
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"I read somewhere that going 1 mm shorter will affect accuracy. What are your thoughts?"

I would think there would be other factors more controlling especially in a Mosin. I guess you can test the theory. I have both types of cases and for me other factors (bullet and load variation) seem to be what governs in my M39.
 
Thanks. I have three bullets types to compare the two cases in sets of five for a total of 30 to try out, maybe Sunday.
 
Years ago I was trimming 220 brass and got a bit carried away. I set the trimmer wrong and trimmed a good 1/8 inch off the case necks of all my cases. It was the only 220 brass I had at that time, so I loaded and shot them in my Ruger 77V. They shot great. Based on that, I can't imagine that 1mm is going to make a significant difference.
 
Good to know. What would be interesting is if you discovered your mistake half way through and then compared the two. My suspicion is that accuracy is the same but off target for each.
 
1mm isn't going to do anything. 1mm = .039".
"...replace all my brass..." No. Norma brass is good, but excessively expensive. Isn't worth the extra money.
 
I did discover the mistake before I overtrimmed them all, but reluctantly decided to go ahead and do the rest. When I eventually replaced the brass (Winchester and then Norma again). The same loads shot into the same little groups.

There are 25.4 mm in an inch. One mm, in my view, just isn't going to matter. If you think it will, trim a mm off the long ones and make em all 53 mm.
 
The length of the neck will affect neck tension. And neck tension will affect accuracy. But, the effect will generally be uniform if the length is uniform. Moreover, the age of the brass (times fired) affects neck tension as well but again if the brass is the same brand/age, it will remain mostly uniform.

So in short: I wouldn't mix headstamps among Norma, PPU, or Winchester, but I would absolutely use the Norma brass..... because Norma is very good brass
 
I couldn't detect a difference between the WIN and PPU but I'm guessing there will be with the shorter Norma. I was hoping to add in the new brass as the old wears out so this complicates matters.
 
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