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View Full Version : Primer swapping - std to magnum



whisler
04-06-2012, 10:09 PM
Having bought an accumulation of primers and powder from my son, who needed the money more than the components, I find myself with some magnum small pistol and magnum large rifle primers that I really don't require. (don't even know why he bought magnum primers) With the talk of possible primer shortages in the future, I don't really want to get rid of them

My question is, if I have worked up a load with standard primers and then switch to magnum primers, should I go all the way back to starting loads and work up again or is there a "safe" reduction of powder charge to use for reworking the load?

I don't have a chrony or access to one. I also don't shoot max. loads.

Thanks for any suggestions.

Wolfer
04-06-2012, 10:29 PM
If your not already at max I would just try them, sometimes they actually help. If not just fall back on your powder a grain or two. I've found you just never know what combination will work best in a given gun.

stubshaft
04-07-2012, 06:59 AM
I would drop no more than 10% from what your shooting now.

rintinglen
04-07-2012, 10:49 AM
If you are in the middle of the road (or perhaps I should say load), substituting Magnum for Standard Primers will have only a modest--perhaps imperceptible--effect. At various times I have done so when I got a super deal on primers, but most of my loads are plinkers, closer to starting than top. If you are at the top end, then by all means drop back at least 10%.
Not long ago Larry Gibson did an informative test comparing magnum, standard and rifle primers in 44 mag cases. IIRC, some of the magnum rifle primers tested increased pressures by 10,000 PSIG. Look up that Thread for some excellent information.

beagle
04-07-2012, 11:24 AM
I'd drop them to starting in the rifle size. #2 son had a Model 70 and had a 4320 load he liked and accidently substituted some Mag rifle primers and it opened a primer pocket. Don't recall the load but it can make a difference and that experience taught me a lesson. Be conservative./beagle