First, let me say this may be the dumbest thing I ever did that I am willing to admit on the internet. With that out of the way... I did it because I love my P7PSP, but magazines are difficult to find and the price is difficult to stomach when you do find one. P7M8 magazines are a little more readily available, but don't work in the P7PSP because the P7PSP uses the heal magazine release, while the P7M8 uses the thumb magazine release.


The critical differences between a P7PSP magazine (left) and a P7M8 magazine (right)

The first step is to disassemble the magazine by depressing the release button in the bottom of the floor plate and sliding it forward. (CAUTION: spring is under pressure, you wouldn't look good wearing an eye patch)

To get rid of the catch for the thumb release. I backed the magazine body with a 13/32 transfer punch. A longer piece or bar stock would have worked better. The transfer punch slid off the end a couple times. A drill bit could be used. I heated it with a propane torch until it was glowing red. Then I beat it with a BFH, (that is a big hammer for you accountant types)

Periodically test fit into the P7PSP. Once it goes in with a little drag, I stopped hammering and started filing until it went into the magazine well smoothly.

I then cleaned off any finish around the seem that hadn't already burned off or been filed off. Then I silver soldered the seem. After cooling, I filed, then sanded the area smooth. I could have filled the dimple with solder to make it look better... maybe later. (we both know I'm never gonna fill that dimple) A little solder peeked through the inside of the magazine body, I took care of it with a rat tail file and some sandpaper wrapped around a wooden dowel.

With the thumb catch eradicated it is time to poke a hole in this thing for the heel catch.

I have a milling machine which made cutting the heel catch very easy. (note the transfer punch used to support the magazine body) It could also be done by drilling an undersized hole and opening it up with a small file. Go slow, check in the P7PSP often.


Factory P7PSP Magazine specs:
  Bottom of opening is  .78" from the bottom (floor plate removed)
  Opening is .31" high
  Top of opening is 1.09" from the bottom (floor plate removed)
  Opening is  .27" wide.
  Each side is .1" from the edge

The one I cut is .27" wide, but is .79" from the bottom, and .29" high. I stopped once it functioned correctly.


The rest is cosmetic, I hit the body with a little black spray paint, reassembled and headed off to the range.

After a lot of hand cycling and 100 rounds of live fire, the converted magazine has held up just fine. Zero failures of any kind.

Parting thoughts:

Buy a P7PSP magazine if you can find them, if not, this is a viable option.
Don't attempt to hammer out the thumb catch without heat. The first one I tried cracked vertically, so I ground it out and soldered an L instead of just the dash (that magazine has held up just fine too)
Avoid PROfanityMAGS, they just don't work.