# Differences in Case Cap.



## Savage260 (Oct 21, 2007)

This is kind of a piggy back from the other question. While I was noticing the "swirl" packing of the powder, I also noticed my FC .308 cases don't hold as much powder as the R-P cases. These are all sized in the same RCBS SB die, and trimmed to the same length. I am using a "max" load of Varget(according to Hornady 45.0gr). The R-P case held all the powder just below the Neck/Shoulder junction. The FC cases held all the powder, but it was up into the neck, and made seating more difficult. Is this going to give me pressure problems? I don't think I would be worried much if I didn't have to turn my seating die down another couple thousanths to get the 155 Amaxs to seat to the same length as in the R-P cases. I also wouldn't be too worried if this wasn't a "max" charge. I have fired this exact load with no pressure problems in the R-P brass, but not in the FC. Any one care to jump in and tell me if I will have any problems with these? After this PD trip out to Western ND I am junking all my old cases and starting fresh with Lapua, so if I have to dump these and toss em, no big deal. Thanks for any and all info!!!


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## ac700wildcat (Oct 30, 2006)

I don't think I'd shoot them unless I had worked up to that load. Sounds like you could really be upping the pressure with a compressed load. I'd rather be safe than sorry and would just dump them. The brass must be thicker on the FC brass than the RP causing the capacity to be less.


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## bigedp51 (Jun 9, 2011)

Your boiler room is smaller on your Federal cases and you will have a much higher chamber pressure.

NEVER mix brands of cartridge cases.

Below, this dates me but the Powley Computer is asking for the internal volume of the case in grains of water. The volume of the case controls chamber pressure, expansion ratio and velocity. Mixing cases causes wild fluctuations in chamber pressure and greatly effects accuracy. (If you don't blow something up first) Please read the "front part" of your reloading manual and you will find the warning about doing this.


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## Coonhunter23 (Aug 17, 2011)

Case capacity varies with brand in my expirence. I have switched between remington and winchester brass and have noticed that the winchester brass has more capacity. This is just my preference, but if your going to buy brass use only one kind. It will increase your accuracy and balence out your pressure. :thumb:


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