How far is your brass growing?
- Thread starter josh_127
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nksmfamjp
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If you have brass moving that much, you must fireform or you will have a mess of splits at the base in a couple loadings.
I don't really have that problem I shoot a 308 NM rifle. I use 300WM cases to make my 308NM case. The 308NM is shorter to the shoulder than the 300WM case. So when I am resizing 300WM cases, I set up and only size to a .003 under the 308NM shoulder requirement. 
MagnumManiac
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This nonsense about brass stretching on the first firing RESULTING in case head separation is so far from the truth that it begs belief.
The case does NOT stretch rearward, the shoulder blows forward and brass is pulled from the neck to fill the void…the ONLY way case head separations occur is if the loader then moves the shoulder back.
What you should do for the first THREE firings is to neck size to allow the case to FULLY fill the chamber, then, and only then, should you bump .001" with spring back.
I can load my comp brass dozens of times without head separation occurring…wonder why?
Cheers.
The case does NOT stretch rearward, the shoulder blows forward and brass is pulled from the neck to fill the void…the ONLY way case head separations occur is if the loader then moves the shoulder back.
What you should do for the first THREE firings is to neck size to allow the case to FULLY fill the chamber, then, and only then, should you bump .001" with spring back.
I can load my comp brass dozens of times without head separation occurring…wonder why?
Cheers.
Lefty7mmstw
Well-Known Member
not with that Bertram brass I was shooting in my 7stw. The belts were so short I actually had a couple casings not make it past the first firing and a few wouldn't fire but had a light tap on the primer. In that situation, the thin brass on the forward 2/3 will grab long before the tail end even sees the bolt. I went to a 30 cal. false shoulder on the stuff but I'm so irritated with it that it's been sitting primed for several years now. I only messed up a box of 20 loading regularly so I'm out much I guess. I do NOT neck size anything, but I do partial fl a couple cartridges. I just switched my 7stw lately to partial fl.
josh_127
Well-Known Member
I've been bumping the shoulder .002 when my nosler brass is formed all the way...using rcbs die to do that and a le wilson neck sizer die to just neck size....I have been using a Larry Willis die to size the bulge at the belt too..which is every firing on the stw....every other firing on my 300 win mag...just shot my stw tonight....81.6 grn n570 was 3128 fps with 195 berger....half inch groups 5 shots....I love this rifle.
josh_127
Well-Known Member
81.8 grns groups opened up to 3/4"...but shot 3158fps average....no pressure signs
