Reply with quote #1
ive also posted this on the gun project forum but it is a reloading question aswell.
i have a BAT M in 6.5x47 Lapua and whilst working up loads i notice that the primers start to extrude into the firing pin hole at relatively low pressures. in the past i have reluctantly run at a much lower node but have now been forced to change to a different projectile that seems to only run well at higher pressure.
i use cci standard small rifle primers as i was under the impression they had the hardest cups out of all suitable primers.
the primers do not have a sharp square outer edge and there is no stiff bolt lift at the load level that the primers have pierced.
it has been suggested that i investigate the possibility that the firing pin itself is too large for the small rifle primer. i was unaware that the diameter of the pin would cause this and thought the clearance between pin/hole, radius and the protrusion would have more of an effect.
i was not aware that there were different size firing pins for large and small primers.
is anyone able to shed some light on what the ideal pin/hole dimensions should be or is there a harder primer that may be suitable?
Reply with quote #2
Aus: give CCI 450 small rifle magnum primers a try. Much harder cup. They will take loads in my .223 F Class rifle that blow holes in standard primers.
Reply with quote #3
did you back off your powder charge or just do a direct swap to magnum primers?
Reply with quote #4
The CCI 450`s actually allow a larger powder charge. Got me up to 3000 fps with 80 gr MKings and W760 or H380 in a .223 Wylde chamber, 30 inch 8 twist MacLennon barrel. Easy extraction. Primer edges not square. Made 1000 yard F Class realistic.