[jjohnson]

Hi, gents!

Hey, I have a bunch of left over small pistol magnum primers - and I don't need them. Any reason I shouldn't use them for 9mm Luger or .38 Special?
Any corrections I need to make?

Thanks!

[ReloaderFred]

Since the 9mm is already a high pressure round, I wouldn't use magnum primers in them. There is so little case capacity, and margin for error, I would stick with the standard primers the data calls for.

On the other hand, you can use the magnum primers in the relatively low pressure .38 special, if you work up your load with them. Don't just substitute them in a maximum pressure load and expect the same results.

Hope this helps.

Fred

[zxcvbob]

When I first started reloading, I was only loading .30 Carbine and 9mm. I bought Federal small rifle primers and used them in both and had no problems -- but I worked up the 9mm load from a starting load and stopped before I got to max. Small Rifle primers are slightly hotter than small pistol magnums.

I'm not saying it's a good idea, I'm just saying it works as long as you start over working up the load. You'll probably get higher standard deviations from using a too hot primer, and significantly higher pressure accompanied with only a small increase in velocity.

[Steve C]

Go ahead and use them but I'd back off max by at least 5% and 10% if they're Winchester's.

[philbo]

...it works as long as you start over working up the load.

+1
I've used mag primers in 9mm w/little difference in performance/velocity after working up new test loads. I treated them as +p, even though I was still within suggested load limits for the load.

[TargetTerror]

Chuck Hawk reported (http://www.chuckhawks.com/primers.htm)that A-square did some tests where the pressure difference simply from switching from CCI 200 to WLRM was 12,800 psi!! That can be the difference between a pleasant, mild shooting load and a bomb. Granted, these were with rifle primers, but it just goes to show that primers CAN raise pressure, sometimes far more drastically than you'd imagine.

With something like the 9mm, which is so small, high pressure, and so sensitive to bullet seating depth, there just doesn't seem like a high margin for error. Sure you could probably use them, but back WAY off first and go up from there.