I posted this short, un-technical write-up on the Sterling Forum of Uzi Talk.com in reply to a question about alternative barrel nuts when SBR-ing a Wiselite/Sterling carbine. It can be found here: Uzi Talk a very informative website. The photos disappeared from the website so I have reproduced the post here along with some followup information.
Uzi Talk.com Sterling Forum – posted: 3-21-2013 – post #11 – Thread started 12-11-2012
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I just sent off my Form 1 and know I have a long wait ahead before I can SBR my WiseLite/Sterling. My first thought is that the stock barrel nut is not going to look right once I cut the barrel off. To see what it would look like, I sat the barrel nut on the receiver tube, took a couple photos, then rotated them 90 degrees. Looks pretty sad, so I am already working on making a replacement that will look more appropriate to the gun.
I made a simple barrel nut that fits the stock barrel’s 5/8”-24 thread. I drilled a hole in the flange and made a spanner-type wrench to tighten it down. Machining a recess in the back of the nut for a lock washer to be compressed into may also help keep the barrel tight.
I realized after making the first barrel nut that after I receive the Tax Stamp and cutting the barrel off, I could easily turn the barrel down and re-thread it to 1/2″-28, one of the most common threads for silencers. I can’t legally cut the barrel off yet, so to help with designing and fabricating barrel nuts, I made a dummy barrel.
My second attempt was to make a barrel nut that loosely resembles the original Sterling SMG muzzle shown below. I thought about cutting off the front end of the SMG tube, threading the hole and using that as a barrel nut, but couldn’t make myself do it to an original piece and ruin a good parts kit. Maybe I’ll pick up an extra one from Apex and try it down the road.
Since the socket head cap screws don’t hold the barrel in on a WiseLite/Sterling carbine, they are purely decorative and tack welded on. I didn’t try to reproduce the offset round stub on the original Sterling SMG required for the bayonet. Also the cap screws are smaller.
The 1/2”-28 thread is also used on most AR-15 5.56mm barrels, so any flash hider or muzzle brake made for them will also fit. I tried a M-16A1 design and I don’t think it looks too bad. The A1’s used a lock washer that may help keep it and the barrel tight. This would be an inexpensive replacement if you re-thread the barrel to 1/2″-28 or you could tap the flash hider out to the original 5/8″-24 if you don’t re-thread the barrel. If you try this, make sure the hole in the device is big enough for a 9mm bullet to pass through. The standard M16A1 flash hider has to be reamed out slightly for a 9mm bullet to pass through freely. Also, depending how far your threaded barrel sticks out of the receiver tube, the flash hider may bottom out before tightening up against the tube. There are a lot of 9mm specific flash hiders made for AR-15 type rifles, but they are threaded 1/2″-36.
Just to see what it would look like, I took my dummy Spike’s suppressor off of my .22LR M4 carbine and put it on the WiseLite/Sterling. I made a flat, threaded disk to hold the barrel in place and to have something for the dummy suppressor to tighten up against. I don’t think it would be a good idea to use the suppressor to hold the barrel on the receiver tube.
I’ve got plenty of time to experiment with other ideas before the Form 1 comes back but right now leaning towards my first simple design, but threaded to 1/2″-28.
NOTE: None of what I have described above has been field tested. For all I know these barrel nuts may crack under stress, refuse to stay tight or go flying down range. 3-21-2013
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Some followup information on the original Uzi Talk Sterling Forum post.
SBRing the Wiselite/Sterling Carbine sounds pretty easy; You whack off the barrel in front of the barrel nut. Done. You could use a hacksaw. But if you want to maintain accuracy, you need to cut it off with something that will insure the cut is square. Best choice would be a gunsmith, cost around $35-$50 to cut and re-crown the barrel. Maybe less since they don’t have to re-thread the barrel or re-attach the front sight.
For the do-it-yourselfer, best (and most expensive) would be using a metal lathe. When I got into SBR’s and suppressors, I went ahead and bought a 14” machine lathe from The Little Machine Shop. The internet makes learning to use one easy. It’s come in handy too many times to count. All of my .22 rifles have threaded barrels now. Made shortening the Sterling barrel a snap.
The second best choice would probably be a High Speed Cut-off Saw or Chop Saw. A lot cheaper than a metal lathe. I have one and use it to cut off the excess barrel length, then finish the barrel on the lathe. Since the barrel won’t require re-threading, this would work for the Sterling. You just have to insure your cut is square and smooth out the sharp edge of the barrel by hand. If you cut the barrel off where the end sits slightly inside the barrel nut, this won’t matter too much.
You can cut the barrel with a hacksaw, band saw, Dremmel, or many other tools. But none that use heat like an acetylene torch. Common sense, right? The more you mangle the cut, the more work involved in making it look good. And most of this will be done by hand.
Regardless of how you cut and finish the barrel, it will have to be re-crowned. The crown is where the rifling ends at the end of the barrel. If it is not perfectly symmetrical, it will affect accuracy. That’s why it’s recommended to clean barrels from the breech end. The cleaning rod could damage the crown. Barrels can be crowned by machine or by hand. Brownell’s sells hand crowning tools. There’s plenty of videos on the internet on how to re-crown a barrel. Re-crowning with a lathe is simple.
If you cut the barrel of and use the stock barrel nut, this is what you end up with.
It doesn’t look very good, but it is the most solid way to secure the barrel. Once tightened and locked, the stock barrel nut will not come off. Something I hadn’t thought of before is it may be possible to remove the locking pin, turn the outside diameter of the nut down some on a lathe so it doesn’t look so massive, then replace the locking pin. I haven’t looked at the stock barrel nut. It may not be possible to disassemble it.
I’ve pretty much covered my other attempt at making a barrel nut in the Sterling Forum post. After making a design that is similar to the original Sterling SMG muzzle, I stuck with my simple, original design. The Sterling SMG look-a-like barrel nut requires the barrel be turned down and re-threaded to ½”-28. Although I recommended it in the initial post, I’m not comfortable doing it now. I’m not sure if it would weaken the barrel to where it wouldn’t support a suppressor. I like maintaining the extra thickness with the 5/8”-24 thread.
I have fired a few rounds from the Sterling through my Liberty Mystic 9mm suppressor. I mounted it with a 5/8-24 Fixed Barrel Adapter. I used the adaptor to secure the barrel. Not an optimal arrangement. That’s why I only fired a few rounds. If it loosens up, I could end up with a baffle strike or worse. It works pretty good with sub-sonic ammo, but until I have a mounting system I trust 100%, I won’t be firing it suppressed.
The Mystic pretty much resides on my 9mm AR/Sterling magazine gun, mounted with a quick release, three-lug mount. The same three-lug mount I used on the 9mm AR/Sterling, will fit the Wiselite/Sterling. But it needs something like a big washer welded to it to properly secure the barrel. Then, switching the suppressor back and forth would only take a few seconds. It will eventually come back up in the round-to-it rotation.
My original, simple barrel nut design works just fine. So far. I don’t have complete faith in using a lock washer behind the barrel nut to keep it in place. It hasn’t come loose yet, but I haven’t shot more than 100 rounds at a range visit. I’m considering modifying the original design by adding smaller, socket head screws on each side, similar to the Sterling SMG look-a-like barrel nut I made. Instead of being for looks, the screws would align with the holes in the end of the receiver tube. The holes in the receiver tube wouldn’t be threaded. The end of the screws would extend into the holes making it impossible for the barrel nut to rotate without them being removed.
The only other modification I’ve made to my Sterling is adding a small Red dot sight. When your eyes get old, you have scopes, lasers or red dots on the guns you use most.
I put a piece of sandpaper on a pipe of the same diameter as the receiver tube. Then used it to sand the bottom of a polymer rail section until it matched the contour of the receiver tube. I took a small section of thick-wall pipe and filed it till it matched the inside contour of the receiver tube. Then drilled and tapped two holes in it matching the mounting holes in the rail section. The width of the metal piece must be small enough to fit through the opening for the barrel in the receiver. Getting the holes in the pipe and rail to line up seems next to impossible. I used wire, tweezers and magnets and finally got them together. Once I got the screws in and the rail centered, I took one screw out at a time and added Loctite. Haven’t had any problems.
I don’t shoot the Sterling too much anymore. When I do, it really draws attention on the range. The title of “favorite gun” changes on a regular basis. I’m still sorting out the 9mm AR/Sterling magazine gun. It’s a lot of fun to shoot and runs well with few malfunctions. But with the suppressor attached, I’m getting some impact shift. To keep it on target with the iron sights, I have to lower the front post a lot and you get a weird sight picture. I’ll get back to the Wiselite/Sterling someday. But not today.
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