seating primers, wont seat flush. 375H&H

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cellfishracing

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I am seating cci large rifle mag primer using a rcbs hand primg tool and i cant get them to seat flush. they are probably a 1/4mm above the base.

Cases hornady 375H&H
Primers are cci rifle mags

cases are new.
 
I have had this problem on several makes of euro cases. Reaming helps but you will also need a "primer pocket uniformer", I think that's what RCBS calls theirs. Anyway it simply cuts away the extra brass at the base of the primer pocket to make things the way the factory should have made them.
 
is it possable that they are fully inserted and still above flush. or that the rcbs hand primg tool is not compatable with my lee shell holder
 
I have used a rcbs hand primer with lee shell holders and not had a problem. The only time that I have ever had primers that would not go below flush it was a pocket issue, and if they are above flush something is not right.
 
I use a primer pocket uniformer to clean primer pockets. The pockets are clean, often down to shiney brass and completely uniform. In general the primer should seat just below flush.
 
i feel like the primer rod in the hand tool dosent extend far enough to push the primer into the pocket, i bought a redding shell holder no diffrence.
 
.... I've no experience with the 375H&H, but I've had a perhaps, a similar experience with other rounds. The "problem", MAY, lie with the Primer Seating center piece. I've two slightly different versions , one is FLAT and the other slightly CONCAVE. ... David K
 
.. 'Have to admit I use the Press to seat the Primers; but it MIGHT be worth a try, using the Concave end of the rod/primer seating "rod" and see if that helps. ...... With NEW Brass, there really should be no problems with the size of the primer pocket itself. ... David K
 
I have this issue with my rcbs handprimer and #4 shellholders when loading belted magnums. They fit flush when loading standard cartridges with #3 shellholder. I think I may have a shellholder which is out of spec? I just finish the seat of the primer with the press mounted primer when seating bullet.
 
If you are going to use a primer pocket uniformer, chucking it in a battery powered drill will speed up the operation if you have lots of brass to process. Check out uniformer sold by Sinclair International. When uniforming the pockets of new brass, dip the cutter in some dry neck lube to prevent chatter and prevent the cutter from grabbing the case and turning it in your hand. The carbon in the primer pocket of fired brass is a good lubricant, and you don't normally need any additional lube when uniforming them. On brass that has already been uniformed, the cutter also quickly removes carbon deposits after depriming.
 
Does the priming anvil extend above flush with the shellholder with no case in it??If it does not then the anvil isn't long enough,never seen this before.My 375 brass has had no issues.
 
cellfishracing said:
I am seating cci large rifle mag primer using a rcbs hand primg tool and i cant get them to seat flush. they are probably a 1/4mm above the base.

Cases hornady 375H&H
Primers are cci rifle mags

cases are new.
Click to expand...

Try seating them in the press, you have more leverage to get them to seat flush. I have had too many ftf with cci, I don't use them anymore for that reason.
 
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