Standard primer, versus Magnum primers?

  • 941 Views
  • Last Post 20 September 2015
Rich22 posted this 20 September 2015

Greetings folks!During a recent reloading session, I ran short of standard primers for my receipe of 38 handloads. Having noticed I still had a nice supply of magnum primers from my .357 mag days. Been always under the impression that in 38 loads mag primers would gift you with larger groups. Soo, I loaded my 550 up with mag primers, 4grs of red dot, and my Lee 158gr RNFP bullet design with 18/20 to 1 tin.Not wanting too many of these rounds around; due to the expected failures, loaded 40 rounds up and headed to the range. With my standard loads i had nice groups around 1.25 to 1.50” at 25 yards off a bench. S0 not expecting to much shot my first group at 1.125. well that was a fluke, so tried my next 5 shots and they shot about .940. So what the heck was going on here? so went home and returned 2 days later with my S&W M60-15. Alwars ran about 2.750 at 25 yards. Now with mag primers that group also schrank. Now this turned out just reverse from my expectations. both types were the CCI brand. Both started with clean barrels, one fouling shot with groups to follow. So what is the norm for the mag primers?? Any ideas would be appreciated??Have Fun! Rich22    

Attached Files

Ed Harris posted this 20 September 2015

I don't have much experience with CCI, but Winchester Magnum pistol primers are nominally of the same mix, drawings and specs, and are simply sorted to segregate primers above mean tolerance for pellet weight, so there is no real difference.

I have loaded Winchester WSP magnum primers in small cases such as .32 ACP, .32 S&W Long and 9mm with no issues and saw no real difference in ballistic uniformity or accuracy. I have similarly interchanged Federal 100 and 200 with no issues as long the firearm had adequate striker indent to reliably set off the heavier cup Federal 200 primer, which resembles the 9mm military primer or .30 carbine primer

I cannot speak to compare standard vs. magnum of other brands of primers.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

Attached Files

Close