[bigin302]

I've got a couple of different brands of brass that I want to load for my 7mm RM. Will their be a big difference in the brass?

[trapshooter]

Maybe, maybe not. Case capacity is a key factor, vs. the charge you are using. Some brands have less internal volume than others. Maybe because the case walls are thicker, maybe because they are different in other ways. Different components really require working up a specific load for each specific set of components.

[swifter]

Could be...:eek: I've demonstrated, to my own satisfaction, that WW brass, fireformed, will hold one full grain more powder than RP or Federal in several of my rifles, all with custom (SAAMI minimum) chambers.:uhoh: YMMV, but I suggest you segregate your cases while the liberals still allow it...:what:

:D Tom

[Bottom Gun]

I've found case wall thickness to vary from lot to lot even with brass from the same manufacturer.

[PaulS]

bigin302,
weight the cases - if there is more than 3 grains difference and you are loading near maximum then segregate the cases by weight. for each 8 grains difference in brass weight there is 1 grain difference in powder capacity - that means that you should drop charges by .125 grains for every grain of case weight.

If you are loading low density and pressure then 3 grains difference won't be enough to notice.

PaulS

[Steve Smith]

I don't know how accurate the numbers are that Paul mentioned, but I agree, if you are ner max loads then you should choose to use one brand of brass. If you plan to load hot and get lots of loadings, maybe you could even cut a few brands in half (lengthwise) and compare the construction of them. Is that going too far?

:p

[Poodleshooter]

Make sure that the cases are all trimmed to identical lengths before you weigh them.
I found that domestic cases in calibers such as .223 vary so much that sorting by headstamp isn't really a good way to segregate or measure capacity. Weight is the way to go. I'm seldom picky enough to bother as it doesn't get much past 300yds around here.

[Bacchus]

You may also want to segregate cases if you have any military brass. Some reloading manuals suggest doing so.

[Steve Smith]

Sorting by headstamp will just give you a safer lot of brass to deal with and will hopefully prevent a surprise like you get when reloading Federal .223 brass.


For those who will ask: Fed .223 has a significantly thinner web and the case will blow much easier than that of Rem, Win, or LC. Cut 'em in half and see for yourself.