Anyone else see the article in the april 20th SGN about the suomi based 9mm rifle? It looks pretty straight forward and the guy said he built it for about $175. I'm sure I have a complete spare set of AR15 fire control parts which would bring the price down as well as various other scrap that could be used. I think I'll order 2 suomi kits and give it a try.
I've been looking over the second article on this build, specifically the magwell. Earlier I posted the deminsions of my Sten MKII kits magwell and thats the spec I'm going to build this magwell to.
I reworked the Suomi barrel shroud to work with the SGN-9 barrel bushing. I liked the idea OLD GRUMPS has about just removing the lugs inside the shroud and thats what I went with. I removed the lugs and the tab on the outside of the shroud. I haven't decided exactlly what kind of sights to use yet. The stock Suomi sights will be way to low to use with the inline stock/receiver setup and will have to be raised like the AR15 sights are. Heres a picture of the alterations to the shroud.
Yep, I got mine yesterday not much in it. It does cover the barrel bushing, magwell, hammer and ejection port as well as the barrel shroud. Oddly enough he didn't cover the ejector or I'm not seeing it.
MOLEMAN,THATS WHAT MY SHROUD LOOKS LIKE. I ALSO CLEANED UP THE FRONT PORTIN OF THE REC. W/ THE LUGS ON IT TO USE AS BBL BUSHING. GONNA ATTACH IT PERM. TO BBL, AND SHROUD PERM TO BUSHING. THERE IS SO MANY DIRECTIONS ONE COULD TAKE THIS THING I MAY HAVE TO DO ANOTHER AND GO WITH A TOTALLY DIFF. LOOK. I HAVE A 45ACP BBL THAT NEEDS A HOME.
The lugged area on both of my receiver chunks were cut so that even if I cleaned them up about 1/4" on the bottem would be hanging out. I know what you mean about building another one. I still have a sten build and I am contemplating building another version of this one first. I don't like the idea of pinning the barrel to the barrel bushing. I think I will just thread the barrel to the bushing. To keep the barrel from spinning either weld the flange area of the barrel to the bushing, or mill out a key slot in the barrel bushing. I suspect though if I weld the shroud to the barrel bushing (leaving the stepped flange area of the barrel) that would hold the barrel tight enough so that no other means would be needed. Isn't a sten MKIII barrel held in a similar fashion with the front and rear barrel trunion?
YES, STEN CAN ROTATE, BUT IT DOES NOT NEED TO BE TIMED(EXTRACTOR CUT) LIKE SOUMI. I WILL WELD BUSHING TO BBL AND DRILL HOLE IN SHROUD AND WELD THROUGH SHROUD TO LUG ON BUSHING. IT ONLY NEEDS ENOUGH TO KEEP IT INDEXED.THEN SLIP SHROUD OVER TUBING,WHICH WILL BUTT AGAINST BACK SIDE OF LUGS,THEN WELD SHROUD TO TUBING. I AM TERRIBLE AT EXPLAINING THINGS BUT I HOPE YOU CAN KINDA SEE WHERE THIS IS GOING.
Don't worry about it, I have a new screamapiller thats keeping us tired too. Did you get any more work done on yours? I was watching my UPS tracking # which said my steel would come today. It came, minus the tubing for the receiver that fell out of a hole in the box. I did a UPS damaged package form, but I'm not holding my breath that it'll show up. About all I can do until I get another receiver tube is the barrel extension.
I guess I got lucky when they cut up my rec. The front part w/ lugs is totally usable as a trunnion/bushing. Everyone elses is cut through lugs/un-usable. I am behind on bolt mods.,I have drilled/cut/filed the slot but I need to find someone here w/lathe wiiling to turn it. So far people are scared to do it, they think they will get in trouble.Have not ordered metal yet but will soon.Thinking about seeing if I can save magwell so I can use drum mags. Mine came w/ a very neat bbl compensator and in my way of thinking if I make bbl,shroud,comp. one piece I should be able to weld extension onto comp. What do you think, would that be legal?
I have only removed the magwell parts from one my kits but the back pieces are all toast, but it looks like I have 1 front piece that is almost untouched and one that is rebuildable with only a little work. I'm working on getting a new rear piece (filler I think its called) for a suomi build. For this build I also think I'm going with the suomi mags especially after seeing the 9mm tommy gun build. I'd wait to turn the bolt down till I had the receiver tube in hand so that you know exactally what size to have it turned down to especially if the receiver tube is a little off spec. I suppose your barrel extension idea would count. I took the front sight off of mine when I turned it in the lathe. It looks like the comp is pinned onto the barrel shroud. The pin that holds it in place has been peened over and dressed down. Its almost invisable. I think that joint would have to be welded like you said. I was just planning on drilling the comp with a 3/4" drill and sticking the lengthened barrel through it.
:help:Yes,I see what you mean about the bbl extensin sticking through comp. No need for comp to actchually work being semi-auto. I have ran into a problem. I cannot get firing pin out. I've got ret. pin out but orig. firing pin wont budge. should I drive it from front or rear? Should I try to drill it out? PLEASE HELP, I'M STUCK!
I thought I'd try drilling out the port holes in the comp into the barrel extension. If I mess it up I'll just make another one and not drill the holes. The firing pin has to come out the front. theres a shoulder holding it in. Its in there pretty tight as you found out but not as tight as a rommy barrel pin. There's a nice cutaway of the bolt somewhere in the weaponeer threads on the suomi builds as well as a punch specially made for the job. I (this is going to make somone cringe) took a 1-1/4" top section of a broken drill bit that measured .107", a big nail with the tip ground off and a section of 3/8" rod. Dropped the drill rod in, then the nail and 3/8" rod. The 3/8" rod was sticking out enough that i could drive it in with a hammer. Nice solid hits and drove it out. Did you anneal the bolt?
You have to drive it out from the rear. Mine was really stuck and i had to give it a few hardy whacks before it began to move. If you've got the cross pin out it should come out.It's about 3/16 " in diameter so you will readily see when it starts to move. Warning I got a punch stuck twice trying to to remove mine. your punch needs a long slender nose so it doesnt catch on the sides. I've been following the thread. I started a suomi before the article by matthews came out, so I've been waiting to see how things develop generated by all the interest from the article. Sounds like you guys are on the right track. I couldnt figure out why the bolt had to be turned down in exterior dimension until I was directed to a BATF memo that said it was a necessity. Seems really dumb since the entire fireing arrangement is changed out to semiauto configuration. anyway luck on theFP removal. Chief4guns
Open bolt subguns only use the FCG to release and stop the bolt from moving so you can control it. All a FA bolt has to do is cycle back and forth to fire automatically. If an unaltered FA bolt can fit and cycle in a semi receiver you have what is known as a "stutter gun", pull and release the bolt handle, gun empties itself regardless of trigger position. Various methods are used to prevent an unaltered bolt from being installed. With a round tube receiver easiest is to reduce the ID and turn down the bolt to match. The Uzi and several others like the PPs43 use a blocking bar that requires a slot in the bolt to clear. Of course ATF has never been consistent, look at the M11NINE semi autos. A full auto bolt drops in, in fact if the semi firing pin happens to jam in the forward position the semi auto pistol will empty itself.
Old grumps, If you annealed the bolt already and are going to use an ar15 firing pin then nows a good time to go ahead and drill out the narrow spot thats right behind the old firing pin. I didn't want to go too big and not have a shoulder for the new firing pin bushing to rest against. You should be able to safely drill it from the back of the bolt with a long or extended .135" bit to about 3/4" away from the boltface. This will be drilling into the old firing pin since you annealed it also. This might help you use a bigger punch to knock the old firing pin out. I'll try to get the diameters and depths of how I drilled it out later.
In between getting an old Ford 600 tractor started after it long winter nap and mowing I got some work done on this build. I had previously made some drill bit extensions that helped me drill out the firing pin channel. I looked around the garage and found a bunch of landscaping nails that were about 3/8". I cut the head off, trued them up in the lathe and used the same drill bit that I was going to extend to drill a .4" deep hole in it. Then I used plumbers flux and solder to solder the drill bits into the extension. I only had one that (I had forgotten to clean the bit end with sand paper) didn't hold while drilling and quickly fixed it. I took a picture of the bits and how deep I drilled them from the back surface of the bolt to the very tip of the bit. I would approach these measurement with caution as the 6-3/4" measurement is very close to the bolt face. I previously had removed the old firing pin and turned it into a bushing. I wasn't happy with a little bit of binding I was getting and "opened" it up with these drill bits from the back of the bolt. The photo with the bolts shows the before and after with the bolt turned down to 1.118" for my 1.5"O.D.x1.122" I.D. tube. I went with the larger tube so I could use the suomi end cap. I'll turn it down for the 20tpi cap threads. I also included a picture of the receiver tube and another tube that is 1.25"O.D. and .75" I.D. that I plan on using as the barrel bushing. For those of you that are going with the 1-1/4" receiver you can also look at other tube sizes to make a barrel bushing out of that might save you some lathe work.
MiG welded the front of my receiver back together. I'm trying to keep the removable barrel feature. I Ordered and received 4130 tubeing from spruce supply, machined out the bottom of an unannealed bolt with a dremel!!!(Nobody told me it couldnt be done). Knocked out the fixed fireing pin and tried to drill the bolt for ar15 Fireing Pin but failed. Burned up 6 bits(good ones). Right now Im stuck on stupid trying to decide whether I'm going to turn down the bolt or try to install a blocking piece in the reciever tube to prevent installation of a full auto bolt. Regardless i think i have to anneal the bolt just to drill it. I just bought a HF 12x36 lathe new so I'm gonna set the gun project aside for a week to get it bolted down and wired in. I'll keep monitoring the thread and post when I feel I've got anything to add. I will be back on it soon cause i can't stop thinking about a project like this once I start it. Chief
Just another note. I ordered the 1.25 tubing thinking it would be a lot lighter but in retrospect i wish I had gone with the 1.5 or at least ordered a piece to weld to thread for the end cap. Overbushing and threading the 1.25 is going to be a bear because the threads will cut almost all the way through the sleeve.The end cap gives the gun that unique look and serves a purpose by the way it's vented to slow the cycle rate(not important to us on a semi auto) But it's still a beautiful piece of work that ought to be retained if possible. I've also looked at a number of trigger setups but believe the ar15 is the ticket due to the thin mounting required. Going to try and go to the Pasadena TX gun show coming up to look at other parts. Will advise if I see anything promising. Chief
Looks good, and I'm jealous of your 12x36 lathe, I have a 9x20 that I think I'm going to eventually upgrade to one like yours. I plan on doing a suomi build and using the 1.5"x.188 wall thickness tube turned down to the 1.462" od for a receiver. Then I thought I'd make a barrel/bolt bushing to press and weld in that would have the barrel jacket lug area back to where the inside diameter of the receiver opens up for the fat part of the bolt. I thought that would be "do"able. Looks like you have the hard part of it done already.
Chief, Looks like we have the same idea about using the 1.5" tube for the endcap. It makes it a little harder build but worth it I think. My receiver is going to be heavier than the original suomi but next to my thompson this will fell like a lightweight. To use the original take down feature the front "trunion" area has to be altered so that an original suomi barrel wont fit inside. I figured that when I do the actual suomi build I'll make the barrel hole smaller so an unaltered barrel will not fit. As far as trigger groups goes I am going with the ar15 group, but think the best one might be a modified remington 48/7400/870/1100-1187 type trigger group. You would have to get a complete trigger group and make a new frame for the trigger/hammer/ sear and guts. The beauty of that design is that it is already made to work with a bar pushing forward and only the trigger bar and disconnector bar would have to be modified to get it to work. If you have one of those guns take a look at the linkage.
Looking at that bolt reminds me of the front of a thompson bolt. I suddenly have a hankering to build a "SGN45". Can anyone who has their bolt already be so kind as to measure the front diameter for me? I'd like to see if there's room to open up the bolt face for .45ACP. Thanks!
Looking at that bolt reminds me of the front of a thompson bolt. I suddenly have a hankering to build a "SGN45". Can anyone who has their bolt already be so kind as to measure the front diameter for me? I'd like to see if there's room to open up the bolt face for .45ACP. Thanks!
Check out the suomi section on weaponeer, someone there altered a suomi bolt for the 45. I was thinking about a 9mm thompson clone after seeing the one here, only using square tubing. I would cut the larger part of the bolt body down to 1" and only about 3/4" long. Then I'd weld it inside either heavy walled square tubing or square bar and then I'd have something that looked like a thompson bolt. Then just use larger square tubing for the receiver, welding on a back plate and barrel bushing.
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