Just got back from testing the sg43 after five test runs dealing with head space and the angle of the bolt to the locking lug in the reciever its alive i ran a 50 round belt throught it with no hick ups  i will post some pics when i get a chance

 The angle on the bolt is 80 degress and the distance between the bolt and the reciever locking area is .030 for the head space with a shell case in the chamber and bolt locked up those # got the weapon to run perfect i had to grind the bolt and then i went to far had to tig it back then got the angle wrong  then had to tig the bolt back again then it downed on me that when the bolt moves to lock in the angle changes du? so then i got the 80 degress im reading the protractor on the inside ring its 100 on the outside ring im dislexic and can 't spell but i can build guns, also the reciever length i have is 17- 3/4 i think it should be 17-7/8  so then you wouldnt have to take so much of the back of the bolt to fit the length of the reciever you can see by the pic comming soon, now i have to see what im going to build next

 

 

 

 

Ok, here is the last photo that BlackBeard has sent me. This looks to be the head space technique that he has described in his above post.

I must say, that this has been a pretty cool build!

I agree midmichigun! Too bad most of us can't do it as we are not class 2 builders and could not afford a transferable sample.   

Black Beard, did you weld up your barrel yet? I was curios how well it worked out. I have heard about people doing it but having extraction problems because of the case swelling in the chamber and either the plug was in too far or not far enough. Let us know please!! If possible photograph your process on it incase it does work!!

Just to let you know i put another 50  rounds throught the sg 43 and the head space changed buy 5 thou and it broke cases when i looked at the bolt i could see it moved that locking area like wore it by 5 thou so i re head spaced it to 25 thou thinking it will go to 30 when i shoot it i will let you know after the next test its just a matter of testing till i get it right since there is nobody to help me im surprised nobody else is interested in this reciever build i might do a semi when i get this one right

I am very interested in the SG43. Problem is, no one has an ATF approved design for the average guy to build yet......as far as i know.

The locking shoulder and bolt flaps are usually hardened to prevent things like that. You might want to try and case harden it after you reset the head space. Then it won't wear as fast.

I made my firing pin for the bren build by welding a piece to the original to extend it for the striker. I case hardened it by heating to a purple/dull red color and dipping it in used motor oil. I did that 2 times. Then i tempered it after using the same method and dipping in water. After you harden it is super hard, but brittle, that is why i temered. The pin has had hundred's of hits and no sign of pin deformation.

yes you are right im going to harden it

I'd definitely like to hear more and see some pictures about how you handled the barrel...  Please let us know!

Im working on the barell i used a 3/8 grade 8 bolt i countoured the bottom to fit the crown in the bore i started threading it but then i machined the treads off so i could get the crown where i wanted it,  cut it and left about 1/2 inch pounded a 7.62 bullet down the bore and put in my part i made set my lincoln 255 mig to 20.6 on the digital amp setting and filled in the hole then i started pounding 7.62 bullets down the bore looks good, on the chamber side i put in a 7.62x54 cass then put in my part i made and welded that but i still have to shoot it thats the real test im happy with it and confident ive got 1/4 inch of weld ore more on top of the part and im using 7014 so its 70,000 pounds per squar inch shooting will tell one thing is i cant f--- it up becuse it already f----- up i will let you know when i shoot it

midmichigan

I just got my parts kit today.  What skill level of welder are you?  Your job looks really good.  I'm not a welder so I will have to find a person up here in Anchorage were I'm stationed with the Air Force.  When I talk to welders/machinists up here what shoudl I ask as to determine a skill to make mine look as flawless as yours.  I would learn weldng, but since I fly for a living I have been advised not to even with all the eye protection since it will show up in my yearly physical and my cause me to fail (the Air Force is very picky).  My goal is a mock up only, no semi auto, but want all the parts to move.  Thanks for any advice, feel free to use my email (Timpemberton@netzero.net) 

Blackbeard, I missed this thread in real time.   Really great build going on here. Nice SG43.

to answer timm,s question welding for 40 + years started in high school and im still welding mig tig stick im 60 and gun doctor it runs graet on the right ammo my head space i moved it to .020 i havent got any requests to help any body didnt think any body was interested in this build

New member here. Amateur gunsmith. I just got my SG43 kit (my first gun build). I was just wondering, how do I determine the overall length of the receiver? Thanks in advance for any info!

Black Beard

What did you use to make and jig.  I got my receiver all cleaned up with a drimmel to be welded.  If you have any pics to help me build it, that would really help.  I want to make the jig and have it ready to go, when I go shopping to find a guy who can weld this for me.  On another note how many years did you do in the Army, I just completed my 21 in the AF.  Thanks

And I thought building replicas was a challenge. Nice work there.