OK gang, give me your advice.
I am just about out of WSP primers.
I am reloading for 9mm 125gr TC Lead bullets with 3.2gr of W-231 powder.
This is my most accurate load.
I also go up to 4.0gr of W-231 my newer 9mm so it will cycle with a stronger spring.

All of the data that I took this off of long ago gave between 3.0-4.5gr of 231.
As usual, my reloads were worked up from the starting load.

I have 50 WSP primers remaining and then I start loading with the 2000 SPM primers that I have. [1000 Winchester SPM and 1000 Federal #200 SPM]

Am I figuring correctly, that if I continue to load ONLY my 3.0gr loads with the Magnum primers I should be OK??

Eric

Eric, when I started handloading I was taught that a magnum primer was pretty much the same as adding an extra grain of powder.

Now I can't be sure this would apply with your loads, but what I will say mate is that the magnum primer will give you more oomph.

I'd load a few and put 'em over the chrono to see how much of a difference they make. I'd also be having a good look at the empty cases for signs of pressure.

Cheers, Vince

Eric, I’m not going to give you advice on this because I wouldn’t do it myself!!!

I will offer this precaution instead. (I’m sure your already a where of it)

The 9mm case has a very small capacity that causes it to be on the sensitive side.
Should you find yourself needing to go below min. charge weight pay particular attention to how much empty case volume you have.
The extra strength in the primer could in theory move the bullet before the powder ignites. The result would be the same as if you had a barrel obstruction.

This is not a theory of mine but that of many experts who have studied the issue.

I agree with 221 on this. Since one theory involving the mysterious old problem of 3.5 grains of Bullseye in .357 Magnum cases occasionally destroying guns is that, due to so much empty space in the case, the primer flash shot past the charge and burned back towards the case head causing excessive pressures (a theory I have no idea as to right or wrong), your magnum primer's much hotter and stronger flash could well create the same situation in the 9mm case. Couple that with minimum or below charges and the vacant space could well create a serious problem in your firearm.

Drop the powder weight 10% from the maximum powder charge listed and work up from there and you will be O K.

By The Way...Your 3.2 grains of W-231 is just fine with a magnum primer. It will be a bit faster then with the standard primer by about 25 to 50 fps.

Primers are just the match that starts the fire. Magnum primers are like using a wooden match instead of a paper match.

A lot of people recommend going to a magnum primer when shooting in extreme cold temps to get your hard to start powders going...

Thanks guys.

I received the response from the folks who I was hoping to get it from.

I am planning to load a magazine full of loads using 3.0gr of 231 with the magnum primer.
Later today I'll go to the range and shoot two magazines. One with the small pistol primers and the other with the magnum, and I will see if there is any big difference.

Also, all of my loads fill up the 9mm brass just fine, so I'm not concerned about that possible problem.

Thanks for all of the help.

I was pretty sure that I was OK with what I was doing, but in reloading, pretty sure isn't good enough.

Eric

Just be careful to not go below minimum charge, Eric. Not worried about detination because it hasn't been proven, but a stuck bullet is/or can be embarrassing...

I did that once Bushy, several years ago.
I reloaded a box of 9mm very quickly, for my Witness, and forgot to put a charge in one casing.
Luckily, I was alone at the range when I pulled the trigger, but then, I had to have a friend help me hammer the bullet out of the barrel.
I still am reminded about that one.

Eric