Square Tube Pistol Build

Square Tube 45 ACP Pistol Build  by azhonkey

Here’s the plan, I decided to use a cz-26 mag for the build. finished the magwell today, next will be the FCG.

The magwell is made from a piece of 1x1-3/4 .065 rectangle tube. Aircraft Spruce sells it. I machined a 1/8" slot in the front and a 1/4"in the back. Then added a .065 filler strip in the front and tigged the seam. This tubing will work for all 9mm and 7.62x25 mags. It should work for the 45 Thompson also.

I finished the FCG, the only problem was the disconnector was to short. I need the hammer to be above the tube about 3/16 of a inch. I added length to the disconnector so it should be good to go. Here's what I have so far. Next will  be the bolt. I’m not sure if I’ll make my own or modify one.

The safety lever is a Suomi take down latch. I cut off the original shaft and tigged a AK hammer pin to it. I marked its location to the back of the trigger and machine half way thru the pin so its slotted. Off safety, the slot will be in the vertical position almost touching the  back of the trigger. When you push up the latch it rolls over the top of the rear  part of the trigger which locks the trigger. Very simple design.

I finished the trunnion, barrel and a couple of other things this weekend. It looks like I’ll modify a pps-43 bolt instead of making one. The trunnion is copied from an Uzi.

I finished hogging out the bolt and added some mass back by filling in the recoil spring slot.

I cut the slot in the receiver for the charging handle and finished up the bolt. Next will be the ejection port and set the headspace for the front trunnion and weld it in place.

Since the pps-43 uses the end of the recoil spring guide rod for the ejector I need to come up with something different. I took a piece of 4130 x.187 and ground the profile to fit the slot on the bolt. As soon as I figure out the location I’ll cut a 3/16"slot in the left side of the receiver and weld it in. Next I will cut the ejection hole in the side of the receiver.

I cut the ejection port and welded in the trunnion. Then put a round in the chamber and closed the bolt. The extractor locked on and pulled it out, so next I need to cut the slot for the ejector. I also finished the rear spring cup to lock in the bolt. Next to throw on some sights and give it a test drive.

I hung a front and rear sight on.

The firing pin was either too brittle or too soft. I finally made one that works. Ejection is go od but the recoil spring is still a little tight, I might take out a coil o r two. I ended up using a spring from a sten. I have to finish the thumb safety and a little welding and it will be ready for the finish.