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Sharing my hammer fired PPSH design here. Been meaning to post this for over a year but it’s taking this long to work out some kinks. Finally, I am ready to post about the lessons learned. Picked up a polish parts kit from Robert RTG in 22’ as well as a 9mm barrel from apex. The kit was freaking nice, probably unissued. submitted my form 1 immediately, approval took about 30 days back in spring of 23’. I got started working on the trigger mechanism while I was waiting for the form 1 to be approved. Many guys do the striker fired design, nothing wrong with that, I was just determined to make a hammer fired mechanism work. I read that an sks trigger group will work but never saw a good write up on it. So I bought an “incomplete” sks trigger group for $40 on apex and made it work with the ppsh trigger housing. I didn’t make any mods to the sks trigger at first, wanted to see what would work /fail first so I pinned the sks trigger housing to the ppsh trigger housing. I then had to machine the lower receiver of the ppsh to make room for the sks hammer and disconnect or to protrude through. I welded an extension to the disconnector so that it engaged with the ppsh bolt, it just needed to be .200 longer and .060 to one side, talk about precise welding. This disconnector is important bc it prevents someone from pulling the trigger while the bolt was out of battery. I welded in a simple blocking bar to the lower, and notched the ppsh trigger housing accordingly and wala I had a semi auto lower. Now for the fun part: The bolt modifications. I still removed .900” from the back end of the bolt just like a sticker fire design but didn’t reuse the cut off material. I removed the fixed firing pin, turned my own firing pin housing on a lathe that fit the same hole (thru hole was for an ar style firing pin), relocated the recoil spring to the side of the bolt by machining a pocket with a ball end mill that the recoil spring drops into, machined out the base of the bolt with a ramp that would cock the hammer after being fired, started with an AR firing pin but ended up having to modify it slightly, made a firing pin extension out of tool steel for the hammer to strike, and lastly welded in a blocking bar to the upper receiver as well as a respective slot on the bolt for it to ride. Many guys who run 9mm in ppsh mags have nosedive issues as well. The .220” difference is cartridge length is the culprit. I was no exception to those flaws. I have modified my drums with .187” steel spacers that I welded in place but haven’t gotten around to modifying my stick mags yet. The spacers worked good after I dremelled the each spacer into an acceptable feed ramp. No issues welding the receiver back together, it’s straight enough, I see flaws but most guys don’t. I recommend using an aluminum or brass backing plate to minimize cleanup on the inside of the reciever. It’s hard to clean up welds on the inside of the receiver with a grinder, a dremel works but it’s time consuming. fitting the barrel was simple enough. I cut the 1/2-28 threads off the front. I wanted an “original” length barrel to utilize the primitive muzzle brake. If you leave the threads, the barrel sticks past the front of the brake. Didn’t worry too much about recrowning, just lightly sanded the muzzle. You must match drill the barrel to the trunnion. I set the barrel to my desired depth in the trunnion. You could bottom the shoulder of the barrel out on the trunnion, which is probably what you would do with a tok barrel, but I placed my barrel closer to the magazine due to the .220 difference in cartridge length of the 9mm. The barrel was soft enough that a new TiN coated 1/2 drill bit worked great, go slow. finished off the build with armor black cerakote and she’s looking good. All in: $650 parts kit (now they are $500 with a 9mm barrel on Bowmanarms.com) threaded barrel from Atlantic: $150 sks trigger group from apex: $40 3 drums($80ea): $240 3 stick mags ($50 ea): $150 Tax stamp to the man: $200 Total: $1430 Honestly this was a big project in my book, I was happy to take it on but I easily have a few hundred hours invested. Nothing cooler than shooting my ppsh though next to some guys at the range that just dumped over a grand into their PCC. The ppsh draws some cool attention for sure. over 1000 rounds of 147gr AAC through it at this point with many hick ups. Most of my failure to feed issues improved though after I modified the drum feed lips. Running much better now. Happy to answer any questions about this build, just had to get this off this off my chest. cheers,

Hello everyone! I spent a little time making small statistics from the data that I could find in various sources. This is not a direct comparison of better / worse, no, just a few numbers. I also plan to make comparisons with other SMGs. If anyone has additions or comments, write.