reloading .357 mag question

[.357 mag]

Hey,

I have been load ALL of my .357 loads with mag. primers. I have heard that mag. primers are not needed with lighter loads. Is this true? What is the pressure and fps differerance between standard and mag. primers? I'm loading .356 lead cast 158 grain swc with 5.6 grains of univeral. O, I'm just plinking and having fun. Nothing more.

thanks in advance,

.357 mag

 

[joneb]

I it depends on the powder and how cold the ammo is when you shoot it. For upper end loadings I use AA#9, and I have better accuracy with standard primers, but in cold temps. the mag. primer may be a better choice. Load data for H-110 and W-296 always lists Mag primers.

 

[Unclenick]

Basically any fine ball powder in the medium to slow burning rate range can derive some ignition consistency benefit from magnum primers. If you have access to a chronograph, you should work up your loads both with and without them and see which has the more consistent velocity in your gun? Cold weather, as mentioned, is another reason for them. You can also use the Winchester LP primer that is a dual purpose primer, covering both standard and magnum cartridge needs. I believe it accomplishes that by having standard primer brisance, but with a longer sustained flame. I've never heard any complaints about accuracy with it and know several bullseye shooters who use it happily.

 

[.357 mag]

thanks guys!

 

[The_Vigilante]

Aren't the large pistol primers too large for the .357?

 

[warnerwh]

The .357 takes small pistol primers.

 

[afish4570]

357 large primer cases......very unusual but a found a few too....

Forget what brand they were but I had picked some up at the range several yrs. ago and threw them in my (junk drawer) I mean cartridge collection if you could call it that. Keep you eyes open when scrounging brass you never know what you might run into. Small Pistol Primers are the standard for 38/357.afish4570

 

[AlaskaMike]

Early .357 mag cases used large pistol primers.