Federal GMM Brass

[Wild Deuce]

I tried a few variations in the search feature and can't find what I am looking for.

I have some Federal GMM brass (stamped "FC .308 WIN"). When I did a weight comparison with my other .308 brass from Winchester and Black Hills, this brass was much heavier and actually equalled my LC NATO stamped brass in weight.

Will I have to make volume considerations for this brass (like I would for 7.62 NATO brass) even though it is stamped .308 WIN?

I do not reload yet but I am preparing to take the plunge.

In case anyone is feeling generous, I have an inquiry at this thread that has not received a reply yet. Thanks.

 

[BsChoy]

Any time a type of brass comes in to be heavier than another, it means its thicker and that means less powder space and higher pressure with equal charges. Cut back to starting levels and work up.

 

[LB7_Driver]

I'm using Fed GMM brass to work up a 308 load. It seems a bit softer than other brass, and shows pressure signs earlier.

Otherwise, it seems like good brass.

I have heard that Federal 223 brass is best avoided for reloading purposes. This seems to be from a thinner web area than other makes of brass. I have not of heard similar problems with Federal 308 brass.