45acp DI carbine build

[JGSFAB]

Starting with the shortest gas system possible. Don't know if it will run anything less than full house loads but it will be suppressed 100% of the time.
Hopefully I don't need 45 super type loads.

Read More

 

[Wombat of Doom]

Starting with the shortest gas system possible. Don't know if it will run anything less than full house loads but it will be suppressed 100% of the time.
Hopefully I don't need 45 super type loads.

View attachment 1995688 View attachment 1995689

Any particular reason you are going DI as opposed to say, CMMG RDB? What bolt and barrel are you using? (FTR, just really, really interested in AR options for 45ACP)

 

[JGSFAB]

Any particular reason you are going DI as opposed to say, CMMG RDB? What bolt and barrel are you using? (FTR, just really, really interested in AR options for 45ACP)

I'm using a BCA Socom stripped up and BCG.
Barrel is being carved from a 416R turned blank. I will note it could be made from a blow back barrel by cutting extension threads and some turning. It's certainly been done and I know of one that runs, basically replicating that gun with my own touches.

Something I'm kind of struggling with is it would be the prefect application for a double feed 45ACP magazine but it's hard to find one that exists.
It's not that it's hard to make a 45ACP stick mag lol. Double feed would solve so many issues, loading and feeding are the top IMHO.
Hell LRBO is way easier.
I've looked at all the common stick mags, when they go 45acp it seems to drop to single feed.

 

[old greg]

This is a really cool project. Machining is my day job so i enjoy seeing your work

 

[oa98pistol512]

I'm using a BCA Socom stripped up and BCG.
Barrel is being carved from a 416R turned blank. I will note it could be made from a blow back barrel by cutting extension threads and some turning. It's certainly been done and I know of one that runs, basically replicating that gun with my own touches.

Something I'm kind of struggling with is it would be the prefect application for a double feed 45ACP magazine but it's hard to find one that exists.
It's not that it's hard to make a 45ACP stick mag lol. Double feed would solve so many issues, loading and feeding are the top IMHO.
Hell LRBO is way easier.
I've looked at all the common stick mags, when they go 45acp it seems to drop to single feed.

Thompson

 

[JGSFAB]

Thompson

Kind of bulky IMHO.
I have something on the drawing table, something correctly curved.

 

[JGSFAB]

So instead of glock mags, I'm doing this... Lower is going need some bolster plates on the magwell .
Might have got a bit carried on the rounds , 52 is a bit much. When it took all of my 350mm print bed that should have been a clue.

 

[JGSFAB]

Well after junking the large prints I finally got one to mess with. Lug contact is good but no feed, off to the next. MK2.5- Moved the round back and feed ramps built into the mag. Seemed to work better, still needed some generous feed ramp reworking. Not easy to get these Short N Fat Boys in that hole.
Chambered the barrel , set the extension, drilled the extension pin, trimmed a gas tube to 2.3in sticking out of the gas block, and drilled gas port.
Set the barrel nut with a good old pipe wrench then had to clearance it to clear the gas tube. Took some tweaking but I got the gas tube nice and lined up with the gas key. Just need to rob parts from another lower to build it out. Dummy round are feeding by hand, dunno if its gonna BRRRR but if it runs and doesn't pepper me with powder - mission accomplished.

 

[JGSFAB]

View: https://youtu.be/587goWeMvHo?si=f0VHMSuK8JPwY9wY


Man that brass refuses to move up that bolt face.
Flared lips might get it tilting at the right angle sooner? IF I drop right at the back of the lips it's slow enough to pickup and feed.
Moving the stack back is probably the solution, it's just taking more none existent metal out of the lower. Dowhatyougottado I guess.

 

[JGSFAB]

Hitting an HARD wall trying to this "THING" to work.
Lug contact isn't good, everything has to jump to much.
Gonna see if I can get the mag higher with BCG clearance I guess.

 

[JGSFAB]

Got the ol Faithful Glock mag lower feeding nicely. At least I might get to cycle test the upper with the GLOCK lower.

 

[Juniper9mm]

Thanks for sharing. This build in on my list.

 

[JGSFAB]

I guess its back to never give up...
Some BCG profiling and I can raise the mag 0.050", as the old saying goes "a thou is a mile".

 

[JGSFAB]

View: https://youtube.com/shorts/KMGyCXxqK9g?si=DSMM-kQqI6QJqauw

 

[JGSFAB]

Seems to be feeding now! Squirting a Polycarbonate-CF copy now... Haven't even tested the gas system.
Everybody loves a project gun.

 

[JGSFAB]

View: https://youtu.be/fpIr25CsNwU?si=6P2LcM3VWzVEsVF0

Pretty weak Unique loads , got a couple LRBHO s. Thinking extractor is hanging on the brass causing FTEs

 

[JGSFAB]

Well this is the most consistent Failure to Eject I've had. 9 out of 10 end like this.
I have seen some lock back but I guess I'm going to make a few rounds to see if it has any effect. Slow mo shows it spinning in the reciever... I do have a heavy buffer so many time to try a hollow buffer, one weight so it still hammers home.
The bolt has zero lockup issues now takes little effort to chamber. Feeding is fantastic if the cases would eject

 

[JGSFAB]

Empty buffer = function Better anyhow, tried to run it fast and it FTEJ'd
Some carrier lightening might be in my future.
A dual ejector bolt couldn't hurt either.
BUT I got most of a mag to run, happy happy!

 

[Duneblaster]

Modern .45acp bullets have a blunter profile. Similar to .380acp & the 9x18 Makarov. The truth is, the 9mm is built for reliable feeding, tapered case, a smaller gap behind the rim of the case, with an aerodynamic bullet shape. The switch from the old pointier shaped .45acp bullets to the more blunter shaped bullets is why the 1911 went from reliable to unreliable. That 2pc feedramp and the mags don't play well with the modern projectiles. Same with 10mm and .40S&W... but we all love the 10mm... kinda...

 

[JGSFAB]

Modern .45acp bullets have a blunter profile. Similar to .380acp & the 9x18 Makarov. The truth is, the 9mm is built for reliable feeding, tapered case, with an aerodynamic bullet shape. The switch from the old pointier shaped .45acp bullets to the more blunter shaped bullets is why the 1911 went from reliable to unreliable. That 2pc feedramp and the mags don't play well with the modern projectiles. Same with 10mm and .40S&W... but we all love the 10mm... kinda...

It is what it is. What's great is it's feeding really nicely. Just need a faster bolt to get the cases out of the receiver.
Lighter = faster.