What are magnum small pistol primers used for?

dakotashooter2

Checked the gun shops and that pretty much the only thing they had left and in significant quantities too. I use SP primers in 9mm,40 and 357 and don't recallseeing any loads in the firt two that call for mag primers.

FWIW I have a decent stockpile but was gonna grab another 1000 of SP or LPs to ad to my inventory and the normal supply that was there two weeks ago was gone from all the stores.

dcs shooters

I'd use the sp mags in the 9mm and 40 as long as your load is not max. If it is, back off the powder some. In loading 44mag. for years, I didn't see very much difference in fps or pressure from standard or mag primers.

79mustang

When I first started reloading I wondered if using mag primers in place of regular would hurt. I talked to some very experience shooters and this is what I learned. If the caliber says mag example 7mm mag, 357 mag, 300wby mag you use a mag primer. This is true but some others do also. Most wild cat cartridges, like ackley imp's. Using a mag primer in place shouldn't hurt nothing just watch for high pressure signs. You might even be able to use a little less powder, to keep the same velocity.

hrbie

Someone please correct me if i am wrong.But i think that a mag primer also helps in loads when you are using a very low amount of powder. The mag primer helps create a more even burn throughout the case.

B17-P51

I inhereted a S**tload of SR magnum primers and was all prepared to work up a new 223 plinking load. When I substituted the mag primer for the standard and didn't change anything else the difference was 36 FPS. No big deal there, light load anyway.
I do use them religously however for large caliber handgun hunting loads with large amounts of relatively slow burning powder. .i.e. 44mag w/4227 or 2400 with a heavy bullet. I would probably do the same for a load with an SP primer under the conditions stated above.

richarda

Primary purpose of Small Pistol magnum primers is for loading H110 or Winchester 296 powder in the .357 magnum. It was formerly thought that they should be used in the .357 with 2400 powder, but the late Speer manuals say that is not so.