I just did a 9mm conversion of the PPS-43. I posted what I did on the AK Files in the gunsmithing section.
I have a PPS-43 Pistol that, of course, fired the 7.62x25 pistol round. With that ammo getting scarce and expensive, I decided to convert the gun to 9mm NATO.
I used a KP-44 barrel, and all the was needed was some minor modifications and it slipped right in. It uses the original bolt and magazines without any mods to them at all.
Here are the pictures of the process.
Original PPS-43 barrel on top, KP-44 barrel on bottom
First operation was to turn the muzzle down to .529 in order to slip into the muzzle brake.
Next was to reduce the diameter of the barrel on the chamber end and to reduce the thickness of the flange.
Last step was to mill the clearance for the barrel trunnion. Using a mill was nice, but this can easily be done with a hand file, which I used for the final touch up.
Completed barrel modifications.
Barrel has been touched up with cold blue.
Another pic of the flange. You can see the relief cut where the barrel and flange meet.
9mm rounds loaded in the 7.62x25 magazine. The rounds did not "walk" and all rounds fed without a problem. Magazines will hold 34 rounds.
9mm round in the unmodified PPS-43 bolt. Fits perfect. (Box of my reloads)
Barrel inserted into the trunnion.
Barrel assembled with the receiver.
KP-44 barrel is slightly longer than the original PPS-43 barrel, which is why the muzzle diameter needed to be reduced.
This pin is the only thing you need to remove in order to get the barrel out. Save it and reuse it.
Test fired 4 magazines thru this and not a single problem. A simple adjustment of the elevation was all that was needed. I removed the hinge pin between the upper and lower receiver and drilled it out to 1/4 inch. I'll use a bolt to hold them together. A bolt will allow me to separate the upper and lower for easier cleaning