Hey guys, I think I did a major no no. I recently loaded a batch of 38 special rounds for plinking in my .357. In a bit of haste I used small magnum primers instead of standard primers as called for in my manual. Is this going to be a problem or am I OK? To me, it would be better to loose 50 bad .38 rounds than to see someone get hurt.
Any help and opinions would be greatly appreciated.

I have never used magnum primers for anything, or felt the need to. But, if your .38 loads are on the light side I don't think there should be a problem. If they are max loads to begin with the magnum primers might cause excessive pressure.

As I read it, you were loading "plinking" loads, which to me are pretty light loads. Since you're shooting them in a .357, I really don't think pressure is going to be as much as my normal .38 Special loads for use in a .357. It's hard to over pressure a .357 when you're using .38 Specials.

One of my favorite "accurate plinking" loads is with a 158 gr semi-wad on top of Win 231 with a magnum primer. They are fine to use.

I would use them but agree with green here...never used mags for anything and for clean burn, velocity, accuracy, never felt I needed them.

I'm with Paul on this one. We run some 38spl that could easily overpressure an alloy framed/cylindered 38spl gun. I have run TONS of those kinds of loads in my 357mag with nary a thought about hurting them. With a maximum pressure of 40,000 (somethings, whether psi or cup at present I can't remember) it's going to take quite a 38spl load to approach that level. Unless you are running a load that is already close to that level and then switch primers you shouldn't have a problem.
Granted, it is going to make a difference but it shouldn't cause a problem. What difference? There will be an increase in velocity, most likely in the 100-200fps range. That would translate into more recoil and it may affect point of aim/point of impact and that would be bad for fixed sight guns.


Before you go out and shoot them though with these suggestions could you share the exact load with us. The only place or variable that would change my opinion is if you were using Hodgdon's Clays powder. That would just be me seeing I have had a KB while using it. It was in an auto though not a revolver.

Thanks for the great info guys.Being this reloading thing is fairly new to me, I need all the help I can find. Heres what I was loading.I went with the Winchester 231 powder at 4.8 to 4.9 grs. with a 125 gr jacketed hollow point. I got my load info right out of the Winchester book and it states that 4.8 is starting point and I do all my loads at the recommended starting point.I don't feel I have enough experience yet to go much over that point.
From what has been said, I shouldn't have any problems. Thanks again for all the great info.

P.S. I an using these loads in a Taurus model 627 Tracker and a S&W model 686-2.

I also had the same question.
A while back I bought 2 bricks of 5K win SP primers.

By mistake I grabbed 1 brick of SP mag primers.

So I am happy to see they are ok to shoot mild loads in my model 27.

From hodgdon cowboy action data is found the following info:

38 Special 4.2g trail boss, 158g SWC, 804 FPS, 13700 PSI

357 mag
4.2g trail boss, 158g SWC, 865 FPS, 20400 PSI

Is the extra pressure and velocity due to the mag primer or larger case or both?