Fitting a thread adapter on a short barrel handgun?

[bionichandman]

Hello all! I've been creeping these forums for quite a while now and finally figured it'd be the right site to join if I plan on accomplishing my own silencer project. I'm well versed in the form 1 and paperwork and will be filing it as soon as I decide on which gun I'd like to modify and finalize the design.

A while back I picked up a cheap Hi-Point Model C9 9mm Luger for $100 as the base throw-away gun I'd like to test my first silencer on in case anything goes wrong and because it's a fixed barrel blowback operated gun that wouldn't require a recoil-booster. Since then I realized I made the mistake of not getting the C9 compensated with the longer barrel which I could have allowed me to thread the barrel easily but instead the C9 with it's near-flush barrel barely protruding out of the slide. Hi-Point won't sell just the barrel either so it's back to the drawing board.

I've been thinking for hours on how I could adapt threads onto this barrel but every idea I come up with will not allow the slide to be removed for gun cleaning once the threads have been put on. An old gunsmith said it would be possible to butt-weld a 110% sized inner smooth-bore thread adapter onto the end of the barrel, but again that would be the last time the gun is ever taken apart. I think I've finally come up with a design that should allow the barrel to be adapted properly without locking the gun shut permanently.

I've noticed there's about a 1/8 in (or slightly larger) gap between where the outside edge of the barrel mates to the chamber and the chamber's outside wall which rides against the slide. This means I should have an 1/8th inch of working space between the barrel and the slide walls when the slide is on. So what if I were to increase the bore on the end of the slide to allow a one piece lathe machined "sleeve" with a thread adapter built on the end to slide over the barrel completely and weld at a couple drill points near the adapter|barrel seam and at the chamber. This way the gun will (hopefully) be able to function properly while riding on the new sleeve and can still be disassembled.

My question is very simple, does this look as though it may work if the correct steel is used and the adapter bore is center line with the barrel? I know it may sound stupid spending all this time messing around with a cheap gun trying to adapt it but I'd rather not try my first silencer I've ever built on my incredibly overpriced but oh-so-handsome 1911. I've fitted a compensator to it <3 and I don't feel like taking it off anyways, it's just way too pretty....I mean functional. I've also attached a crudely-drawn MSpaint blueprint to help you folks make sense of my ramblings.

[Bendersquint]

This is how we do barrel extensions as do the other threaders and manufacturers if you sent it out to be done.


BTW you need to fix the link, your picture is micro sized, but I could see enough of it to see what your point was.

[bionichandman]

Sorry about that, guess it didn't work. I'll try this one.

The only thing that concerns me is boring the slide out much more than 1/8 inch because of the clearance for the spring mount on the front would probably weaken the mount quite a bit. Does anyone have experience with getting threads affixed to this style or any other compact 9mm? Thanks for the response by the way, I'm glad to hear it's somewhat possible.

[Bendersquint]

Sorry about that, guess it didn't work. I'll try this one.

The only thing that concerns me is boring the slide out much more than 1/8 inch because of the clearance for the spring mount on the front would probably weaken the mount quite a bit. Does anyone have experience with getting threads affixed to this style or any other compact 9mm? Thanks for the response by the way, I'm glad to hear it's somewhat possible.

You got the concept right, though in reality its done differently. For one it wouldn't be full length, would jus be the last 3/4 inch or so.

Check with ADCO they have done it before, we are too busy at this time to take on this project. Might be able t work you in a couple months though.

[bionichandman]

Okay, so there's no need for the full length then? I'm probably going to have my close friend machine this on a lathe for me, he's got about 10 years in the CNC business under his belt. Forgive me for asking but if the sleeve isn't extended all the way down the barrel to the chamber wont the slide hole catch on the sleeve/weld edge during the forward slide action? That was my reasoning behind the full length adapter, so the barrel can ride on it without catching the edge and jamming during the reload. The slide on this weapon isn't in a defined track, it's held on by a rear firing pin spring-stop and the barrel. Cheap gun >_>

[rogerme]

Easy to do. Here is my old EAA Witness it came as a .45 with the .22 conversion as a set. Barrel way to short for a suppressor. So you make a extension. I also made a brass thread protector a bit larger then the barrel so it has a bit tighter lockup.

[bionichandman]

Oh wow thats what I was looking to see! Thanks for the pics that helps alot. So you just threaded the barrel further down the slide and made an extension that screwed on?

[Bendersquint]

Oh wow thats what I was looking to see! Thanks for the pics that helps alot. So you just threaded the barrel further down the slide and made an extension that screwed on?

THats how it is done, whether it be for a larger diameter threads or just stretching it out a bit.

[bionichandman]

Okay, but what if the barrel seems cheap and thin? >_> What do you think the minimum thickness that I could make the barrel wall when I thread it? Too thin and it will burst won't it? Or does the presence of the adapter threads over the existing thin barrel give it some more strength? I'll take some measurements and get back to you.

[Bendersquint]

Okay, but what if the barrel seems cheap and thin? >_> What do you think the minimum thickness that I could make the barrel wall when I thread it? Too thin and it will burst won't it? Or does the presence of the adapter threads over the existing thin barrel give it some more strength? I'll take some measurements and get back to you.

If you are concerned about it being too thin then I HIGHLY RECOMMEND you leave it to a professional that has experience doing this, than someone that hasn't done this type thing before. Do you want to take a risk for limb or silencer?

[rogerme]

Ditto that if your not sure do not do it. It is nothing more the a barrel extension threads can be very shallow and fine if your starting with a thinner barrel. Most of the time as the lathe will need to be set up to cut .5x28 threads for the suppressor to attach I simple use that for all the threads the barrel is .5x28 but no good for attaching a suppressor to. Ones I have made for others I always use a different thread pitch for the barrel and extension so there is never a question of what goes where. Depending on the shop and there per hour charge and set up time your cost could be 50 upwards of a couple hundred bucks.

[rogerme]

So you just threaded the barrel further down the slide and made an extension that screwed on?

The first picture is the slide forward in battery. You can see just a small amount of the barrel with the coming out past the slide it has the brass thread protector on it you can see the color.

[bionichandman]

Okay, but what if the barrel seems cheap and thin? >_> What do you think the minimum thickness that I could make the barrel wall when I thread it? Too thin and it will burst won't it? Or does the presence of the adapter threads over the existing thin barrel give it some more strength? I'll take some measurements and get back to you.

If you are concerned about it being too thin then I HIGHLY RECOMMEND you leave it to a professional that has experience doing this, than someone that hasn't done this type thing before. Do you want to take a risk for limb or silencer?

Lol notice the name: bionic hand man. I've only got on hand left, and I plan on keeping it so the professionalism may be a good call. The other hand is robotic and thus far unable to handle the recoil of anything bigger than a .22 handgun and forget about aiming with it, more of a novelty at this point lmao. Anyways let me measure the barrel thickness and find out what metal they made it with so I can have a final opinion from you folks. Thanks again for all the insight guys!

[rogerme]

Lol notice the name: bionic hand man. I've only got on hand left, and I plan on keeping it so the professionalism may be a good call. The other hand is robotic and thus far unable to handle the recoil of anything bigger than a .22 handgun and forget about aiming with it, more of a novelty at this point lmao. Anyways let me measure the barrel thickness and find out what metal they made it with so I can have a final opinion from you folks. Thanks again for all the insight guys!

Not poking fun at you but I wished you lived near me. I have always wanted to build a firearm into a prosthetic. Ir simply a snap on set up. My stepmothers ex husband has no arms at all he lost them when he was a kid. I fixed many rifles and shotguns for him he would lay down get the rifle/ shotgun on his shoulder and fire it with a string on the trigger. He was a quite good shot. He al;so drove dirt oval track race cars and yes he could drive a stick...

[bionichandman]

Lol notice the name: bionic hand man. I've only got on hand left, and I plan on keeping it so the professionalism may be a good call. The other hand is robotic and thus far unable to handle the recoil of anything bigger than a .22 handgun and forget about aiming with it, more of a novelty at this point lmao. Anyways let me measure the barrel thickness and find out what metal they made it with so I can have a final opinion from you folks. Thanks again for all the insight guys!

Not poking fun at you but I wished you lived near me. I have always wanted to build a firearm into a prosthetic. Ir simply a snap on set up. My stepmothers ex husband has no arms at all he lost them when he was a kid. I fixed many rifles and shotguns for him he would lay down get the rifle/ shotgun on his shoulder and fire it with a string on the trigger. He was a quite good shot. He al;so drove dirt oval track race cars and yes he could drive a stick...

Lol I just got this bad boy in august.


It's pretty much a fully functioning hand with opposed thumb, conforming grip and 10 pound grip force. Has it's querks here and there, like limited wrist motion and errant signals but otherwise it's an amazing piece of technology. Holds and shoots a .22 1911 nicely but I've broken fingers on it shooting a .38 special before.

[Bendersquint]

Lol notice the name: bionic hand man. I've only got on hand left, and I plan on keeping it so the professionalism may be a good call. The other hand is robotic and thus far unable to handle the recoil of anything bigger than a .22 handgun and forget about aiming with it, more of a novelty at this point lmao. Anyways let me measure the barrel thickness and find out what metal they made it with so I can have a final opinion from you folks. Thanks again for all the insight guys!

Not poking fun at you but I wished you lived near me. I have always wanted to build a firearm into a prosthetic. Ir simply a snap on set up. My stepmothers ex husband has no arms at all he lost them when he was a kid. I fixed many rifles and shotguns for him he would lay down get the rifle/ shotgun on his shoulder and fire it with a string on the trigger. He was a quite good shot. He al;so drove dirt oval track race cars and yes he could drive a stick...

Lol I just got this bad boy in august.


It's pretty much a fully functioning hand with opposed thumb, conforming grip and 10 pound grip force. Has it's querks here and there, like limited wrist motion and errant signals but otherwise it's an amazing piece of technology. Holds and shoots a .22 1911 nicely but I've broken fingers on it shooting a .38 special before.

Thats pretty sweet, I love what technology could do.

[rogerme]

Wicked neat.

[Wicked]

Exactly. Wicked neat!

That is amazing. I shudder to think of the cost though.

[rogerme]

Exactly. Wicked neat!

That is amazing. I shudder to think of the cost though.

6 million dollars! DOOO