Possible casualty ?

[Mush]

I was loading some 300 WM cartrige two days ago, while seating primers with the RCBS ''thingy'' I notice that one primer pocket was a little loose compared to the other ones. It didn't need as much force to sit the primer as usual.

The case is a 2 times fired in my Mark II. First time FLR and the second time only neck sized. There was no other signs of case damage. No ring over the web. The first firing was commercial Federal load and the second about 2 grains before max load with IMR 4350 and Nosler Accubond.

Is there a danger to fire that cartridge?

GreatMush

 

[JasonYuke]

What you have going on is pretty typical in Magnum cartridges opperating at max loads or should say PSI.
I have found this in many cases specialy the 30-378 and my 7mm Rums.

I get about 3 x fired out of mine until the pockets blow out so bad the primer will not seat.

I would try one more time if they seat loose but do not fall out your ok on the bench.

What the big issue will be is if you plan on huning with these loads, metal does funny things in cold weather and you just might find yourself with not primers in your loads.

My advice use the cases until you know your not comfortable with them, if you are practical you will know when they have 100% expired.

You can lower the pressure and increase the life , you may get one more poke per case.

 

[maynard]

Typical with Federal Brass.

 

[Eagleye]

Federal is the worst North American commercial brass to expand primer pockets, even with relatively mild loads. I don't use it unless I have no options. Winchester is much better. Regards, Eagleye.

 

[Dogleg]

Ditto on the soft Federal brass.