Just wanting to know how many people use standard or magnum primers in there .375 reloads and why.

PC,
I use std primers, in small cases, and mag primers in big ones. If the pressure is still low, i fall back a few grains, and then try the mag primers.

also, big cases, and cold weather, always mag primers.

jeffe

Jeffo,

I read somewhere that mag primers are not conjusive to accuarcy is there any truth to that ??

I would use Fed 215M's

PC - When you are attempting to set off a large column of powder, .375's qualify, then you need a magnum primer. Magnum primers are questionable for cartridges like .25-06 or 6mm. In smaller cases, the explosive pressure caused by a magnum primer can create problems with accuracy. They create enough pressure to engage the bullet into the lands before the powder fully ignites.

Unless you just enjoy hang-fires or ignition problems, use magnum primers like all load books recommend.

Thanks zero & jeffo, fed 215m's it is.

The three large case calibres I have loaded the most for in bench style rifles have been the 300 Winchester, 358 STA and the 375 H&H.

The 358 STA was consistently better with Fed 215s.

300 Winchester mostly better with Fed 215s.

The 375 H&H mostly better with Fed 210s and Winchester standards.

Perhaps had I been doing that shooting in the US of A I may have had more magnum primer use in the 300 Win and 375 because of shooting in colder weather.

Mike

I've had better results with federal 215's than 210's in my .375. I was getting large velocity spreads and poor accuracy with 210's using RL15 and 260 gr partitions. When I switched to 215's with the same load the velocities got much more uniform and accuracy improved. My average velocities also went up about 30 fps, I don't know why.

Remington 9-1/2M

Well,

the consensus is 215M's and "I am a sheep therefore I will follow"

thanks for your help folks.

Terry B who has forgot more about reloading than I will ever know has an easy rule...

If its got a belt it gats a mag primer, if takes more than 60 grains of powder it gets a mag primer

makes life simple

I would agree with Mike375 that 210 (and for me WW LR) have given me the best groups. However, our conditions are much like Mike's, hot! I have seen magnum primers blow groups in .375HH loads where the only variable was primer.

I'd work up your load, and as a final measure try switching your primers. If I were going to be shooting WW760 in a cold climate, I'd give up the slight improvement in accuracy for the improved ignition. Ku-dude

I use magnum primers; a good rule of thumb is to use magnum primers when using over 60gr. of powder, especially ball powder.

George

Use either.

The difference will be in your imagination.

Most powders used in the .375 are of "medium" burning speed and not particularly difficult to ignite, therefore don't require a hotter primer (which a "magnum" primer may or may not be). The large volume of powder used in a .375 generally helps cover any inconsistency in primer force or flame duration, therefore it is highly unlikely that you can tell any actual difference between primer performances.

Now, if you were shooting a .22 Hornet . . .