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SGN-9

33K views 295 replies 32 participants last post by  moleman 
#1 ·
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.
 
#119 ·
just came across this article today.

ive been dong a similar build!! with alot of the upgrades mentioned here.

wanted to go with the sgn 9 look though, its nothing like yours, with the orig suommi look.

its not done as i havent been on it for a while cuz of other stuff getting in the way, but its pretty damn close.

if you want to check it out, look for "sgn-10" on weapons guild or homegunsmith.com.

would liek to see how this one came out too if you have updates, moleman!!
 
#122 ·
just came across this article today.

ive been dong a similar build!! with alot of the upgrades mentioned here.

wanted to go with the sgn 9 look though, its nothing like yours, with the orig suommi look.

its not done as i havent been on it for a while cuz of other stuff getting in the way, but its pretty damn close.

if you want to check it out, look for "sgn-10" on weapons guild or homegunsmith.com.

would liek to see how this one came out too if you have updates, moleman!!
Wow! you're doing a great job on yours. I finally got over to weaponguild.com and checked out your build. I like the barrel nut idea. I've started back up on mine and need to order a trigger group before I start on the fire control group.
 
#121 ·
I got a little more work done on the build over the last few days. I got the ejection port cleaned up some with files. I left it on the smaller side so I can open it up as needed. I never did get the die grinder yet. Since my build is going to look mostly like a suomi I decided to go ahead and use the original type charging handle. Since I'm using a thick receiver I'll need to either make a new taller lug or add some metal to the old one to make it tall enought to retract the bolt. I rough cut a slot .325" wide starting 1.29" from the back and 5.56" in length. I centered the slot by using a piece of angle iron and using the notch for the feed ramp. The long 5.56" length cocking slot actually extends to the back of the fireing pin and serves as the opening for the hammer as well. I decided a while ago to get a remington hammer and sear set up from a 870 or 1100. The remington hammer is thin so I shouldn't have to widen the cocking/hammer slot any. Thats where I'm at now, I"ll get a picture of the updates on in the morning.
 
#124 ·
Here's the pictures of the suomi style cocking/hammer slot that I roughed in. Initially I just did the cocking slot, then thought about it and figured the remington hammer is pretty slim so it should work with the same width as the cocking slot, so I extended it to the back of the fireing pin. I found a spring around the garage that I'm using to help keep the bolt forward. I want to use the original recoil spring and I'll need to make an insert to retain the spring inside the bolt. I may end up using both springs for my recoil set up. In the second picture you can see the back of the fireing pin. I still need to clean up the slot a little and square off the ends. I still need to weld on the front and rear fillers, but I'm waiting until I have the fire control group done for that. Anyway that where I'm at so far.
 

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#125 ·
Here's a picture of it mocked up. The structual zip tie is holding it together at this point. There's a picture of the remington 1100 trigger group. The hammer needs to be about where the zip tie is so in order to make it longer I'll have to make a longer trigger bar. I hope to be able to use the suomi trigger and safety.
 

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#127 ·
LOL @ "structural zip tie"!!!!!

great job. teh part that amazes me most is the die grinder, dremel, and files in the photo. your doing this without machine tools!!?!?!!?!? (prob read that before in the thread, but it was a while ago)
I'm cheating a little, I have a enco 9x20 lathe thats the same as the harbor freight ones only its blue. Other than that I've used the drill press and whats in the photo. I used the lathe to make the barrel bushing and thread the tube for the end cap, and the barrel for the extension.
 
#130 ·
I worked a little more on the build today. I made a template for the sideplates, but I'm going to wait to cut them out until I have the trigger goup done. I'm going to weld the front filler to the receiver since the barrel won't be removable. But I want to be able to test fire it before I make the barrel unremovable. I removed the mounting lugs for the front filler from the receiver and cleaned it up some. I'm debating if I want to notch the receiver for the lug or just cut off the center section and I'll end up with the two sections that I can tack weld on to hold the front filler until I'm ready to make it perminate. Heres a couple pictures of the receiver chunk before and after and a pic of the front filler and the receiver lug. I'm leaning towards cutting the center out of the lug and contouring the tops to the receiver. I plan on running a bead of weld down the sides of the front filler where it meets the receiver and barrel jacket since the barrel jacket is going to be welded on also.
 

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#132 ·
I got the rear sight slot cut and installed the sight today. I made a slot .390" wide, 3.55" from the rear of the receiver, and 3.34" long. I tapped the rear sight holes with a #8-32 tap and scrounged up two different screws to hold it on for now. I centered the sight slot by using a piece of paper going from one side of the cocking slot around the receiver to the other side of the cocking slot. I folded the paper in half and marked on the receiver where the centerline was. I laid it out from there. Here's some picts. The sight also extends into the interior of the receiver on the original design to act as a rail to keep the bolt straight. I may have to make the block on the bottem of my sight a little taller and make the groove in the bolt slightly deeper since I used a thicker receiver. It seems to be keeping the bolt straight, but there's not much of the "rail" sticking into the receiver at this point.
 

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#134 ·
moleman,
I would not think you would not need that mutch "rail" tou are using the charging handel to guide the bolt. muttman
I'm using the suomi charging handle so there's nothing to keep the bolt from rotating if the bolt isn't guided by the lug on the bottem of the rear sight. Here's a picture of what I mean. You can see the lug on the non reciprocal charging handle and the step it makes contact with on the semi bolt right above it. The upper bolt is the top view of an unmodified bolt and a picture of the rear sight upside down with the lightened rail showing.
 

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#136 ·
my bad, I got modl's mixup. muttman
Hell maybe I was missing something. The correct SGN-9 build uses a bolt handle which would solve this problem. I'll have to think on this for a while. I haven't cut the slot for the ejector yet because I wanted to wait until the rear sight was installed. The ejector might be made long enough to act as a rail also. I bought a remington 870 trigger group off of gunbroker so hopefully it will be here before too long. I was going to use the FCG from one of my 1100s to set up the trigger group but I found the hammer pin is riveted on the small side. Its not worth wrecking the hammer pin to get it done a week or two early.
 
#137 ·
moleman, Im glad to see you getting your project done. Im stalled on mine. I was gonna get a mill-lathe combo w/ last years tax return, but things came up and the money went away. But Im keeping an eye on yours,so keep up the good work!
 
#139 · (Edited)
Mtdew, sorry to hear you're stalled. Where are you stuck at? I figured you'd finished yours sometime while mine was on the back burner.

Muttman, The total with shipping was $44.99, I got lucky and no one bid against me. I bought it after The 1100 TG I was looking at kept going up and up. I looked at the hammer, sear, trigger, hammer spring and plunger and they seem to the same part shared by the rem 870,1100, and I'd bet the 1187. The tg I bought has a plastic housing which if you were just going to machine the rem tg into a trigger group pack it might not be the best way to go. I'll find the guys web site for you. They're listed as out of stock, but he said he hasn't had time to update the website yet. Here is his site. Remington 870 12g Express Trigger Assembly, Remington 870 12g Parts at WWW.HEDDONPAL.COM They're listed as out of stock for $42.99, but shoot him an email because he said he has them.
 
#141 ·
I did a little more work on the build over the weekend. I made and installed the ejector. On my next build I will make and prefit the ejector in the barrel bushing before I cut the mag and ejection openings into the barrel bushing. I won't weld it in at that time because it would most likely get damaged drilling out the openings. That way the ejector can be placed in the barrel bushing and used as a guide to cut the bigger openings. The problem I had is that it was hard to get the ejector slot centered in my barrel bushing. I finally just put the bolt and barrel bushing in the receiver tube along with the ejector placed in an over sized slot and tac welded it in. I looked around the garage for some scrap heat treatable steel to use as the ejector and finally settled on a piece of the original receiver. I cut an ejector out of the receiver sheet steel that goes on either side of the original trigger housing. Here's a picture of the barrel bushing with the ejector welded in.
 

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#142 · (Edited)
I decided to cut a flat into the receiver just forward of the mag well to mount the two lugs for the front filler. I measured the chunk of the old receiver with the front filler lugs on it and removed that amount from the new receiver. You can see in the first picture the flat spot just forward of the magwell. In the second picture you can see how the "U" shaped lug fits on. . I'll just tack weld it in place for the time being in case I need to adjust it at all.
In the first picture you can see the ejector (outlined with black magic marker) that I previously welded in the barrel bushing and how the bolt fits on it. I left the ejector long so I can trim it back if I need to. I cleaned up the magwell and ejection port a little also, but I'm going to wait to finish until I have it all welded so It doesn't warp or shift and I have to do it again. The 870 trigger group should be here this week so I can tackle the trigger housing next.
 

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#148 ·
On the bastard suomi build I'm doing I'm going at it in two parts. I put in a slightly longer ejector so that it guides the bolt for all but the last 1.5-1.75" of the bolt travel.I would make it longer, but I'd have to extend the ejector slot into the main body of the bolt. I think if I did that It might be a place for a crack to start? I think the easiest way is going to cut and weld on a little shim to the bottem of the rear sight. I could also make a little rail to fit inside the receiver behind the rear sight, but that is going to be the harder route to go. I'm almost tempted to go ahead and just make this a total suomi build and cut the barrel jacket lugs into the barrel bushing. Since I made the barrel bushing a smaller inside diameter than the original, an unmodified barrel won't fit in the gun so I should be ok to have the takedown feature. Maybe I'll mock up a spare barrel bushing and see how hard its going to be to cut the lugs before I ruin the real thing.
 
#149 ·
My remington 870 trigger guard came today! I'll be starting the tg rebuild as soon as I finish the remington trigger group demil and lay out where everything needs to go. The trigger group is one of the plastic ones, but is new. +1 to Heddonpal.com for a fast turn around even over the holidays!
 

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