Gunco Forums banner

.50 Beowulf?

40K views 264 replies 22 participants last post by  TRX 
#1 ·
I'd been planning to do a .50 Beowulf AK with a bent receiver, but a milled Chinese receiver is now laying on my workbench. It's part of some kind of training/DEWATS rifle; the barrel is welded up, the top cover has a few short (and pretty!) TIG welds anchoring it to the receiver, and it's missing the bolt and carrier.

I'll need the following:

.50 barrel

7.62x39 bolt to match the Beowulf case head

bolt carrier and operating rod

.223 magazine (may require some "adjustment" according to the AR15 sites)

modified or full-custom RSB, gas block, and FSB - the .50 barrel would have to be thinned unworkably to match the OEM bits. Though machining them from scratch is okay, I might cheat, saw the rings off, and weld or silver solder them to appropriate-sized tubes

At the moment, the only real point of uncertainty is the barrel attachment - it appears to be threaded into the receiver. I know I saw a chart around somewhere that gave the thread specs, but darned if I can find it now...

Anyone see anything major I've overlooked? Other than the gas and sight blocks, it looks fairly easy.
 
See less See more
#258 · (Edited)
I bought this Texas AK Designs mag adapter a few days ago. It will hopefully let me use cheap AR magazines as well as expensive .223 AK magazines...

This is the "left hand" adapter, as advertised on the TAD web site. It looks nicely machined and anodized. However, the reason the "left hand" adapter is cheaper than the "right hand" one is that it's just the "right hand" one without the linkage to put the mag release on the right. The other brands of adapters I've noticed all had the releases on the left, which is where the AR mag notch is.

When TAD deleted the linkage, the release lost some mechanical advantage. It takes a *lot* of force to push the short, stiffly sprung, smooth-surfaced lever down. There aren't going to be any quick mag changes unless you've been using the Arnold Schwarzenegger Forefinger Workout Video.

I'm going to see how much TAD wants to sell me the various bits to add the right-side lever, since all the slots and holes seem to be present.


The most common adapters out there used to be the ones like Magnum Research sold, with a big ribbed paddle on the left. I'll use this one for now, but I'll keep an eye out for one of those.


edit: this adapter fits a .223 AKM, which is what I needed. I had been looking at the various adapters intended for the Galil. The difference isn't much, as mixing AKM and Galil bits usually works. A Galil adapter would move the nose of the cartridge down in relation to the feed ramp, which probably isn't what I want to do.
 

Attachments

#260 ·
Well, it's further along than hcpookie's .45-70 build, which inspired me...

I have to finish the new shoe for the bending jig, turn and chamber the barrel, make the new gas block, and file the Yugo magwell to take AK-74 mags, and maybe tack some shims on the insides to keep them from wobbling too much.
Then rivet it together and function test.

I'm still tied up full time in the House Remodeling From Hell, which evolved from "fix this soft spot in the floor" to "should have just knocked it down and started fresh." Argh. I work until I can't stand up any more, which curtails things like gun play, auto maintenance, etc. Right now my gun building is limited to what I can do while sitting down.
 
#261 ·
LOL. I definitely understand that. Well good luck with it.
 
#262 ·
Fall 2014 update:

A while back Green Mountain had their 20" .500" blanks on sale, plus free shipping. I snagged one to use instead of the 15" barrel I bought back, uh, the other day. That one would have needed a brake to meet minimum length.

I picked up an RPK flat from AK-Builder; it's identical to the Yugo flat, except it has the AK-74 style magwell. I picked up some AK-74 mags. I also got some .jacketed .50 caliber bullets to load some dummy rounds with, to decide which way I want to go for magazines.
Tujungatoes mentioned some feed problems with the .223 AK mags in his thread over on calguns; I need to ping him and see if he got that sorted out.

My loading press and dies are over at a friend's house; I need to get over there to load the dummies. I'm going to bring my calipers along to measure the barrel of his Saiga-12. I have two Beowulf builds backed up, plus he's piggybacking two more, so we're going to need several gas blocks. We might use the Saiga gas block diameter if it's compatible with the .50 profile.

I found the Alexander Arms .50 Beowulf AR barrel profile; I'll stick close to that if possible.

In further news, I'm reorganizing things to I'll have as much as, oh, about two hours per week to devote to gun toys. Which is way more than the "none" I've been able to get for the last few years...
 
#263 ·
I've got to get busy too, TRX.

The first thing I'd done in years , was the Springfield sporter I did up last fall that I put pics up of. MAN I'VE BEEN A SLACKER !! And that was the first one I'd done in maybe 10 years before that ,,that's serious slacking,,,,

I've got a couple things on the back burner though. A PPs43 in 45ACP. BTW I have to check to see if Green Mountain has the 16" 45 blanks back in stock so I can do the up the PPs43 kit I have, that should be neat to try out! I'm hoping there's enough meat on the end of the barrel so I can just mill the barrel the same as a trunnion would be. Instead of having a separate trunnion ,,by the pics I saw of them ,,it looks like it might be close, I didn't notice the OD when I looked at them while in ,,,Dreaming Mode,,,

I want to add a long break to the PPs43 I have now in X25 , so I can unfold the stock and make it legal, then it will be ,,,,much more funner ! That's minor project #1 , and I've got to call a local smith and see if has time to tap it and pin/spot weld it on.

Maybe that will get me motivated to do something afterwards, still need equipment to work with though!! That's why it's so hard to do anything or even get motivated now.
 
#264 ·
That forward magwell made good design sense, but it's sure a hassle with NFA regs...

I bought two of the PPS43 kits, some flats, and some extra mags a year or so ago and put them in the closet to do something with later. One will be basically standard except for being 9x19; I have the reamer, and 9x19 is supposed to feed OK through the mags. It really should have an SBR stamp, but my funds for that went to the Magal build, so it'll probably get a fake suppressor.

The second kit, I want to do something demented. I'm still waiting for inspiration. <grin> I saw one where the builder made a new nose section with all the cooling slots, except long enough to cover a 16" barrel.

BTW, check this Sten build out: http://www.weaponeer.net/forum/forum_posts.asp?TID=6422&PN=1&TPN=1
 
#265 ·
Tujungatoes said he had no problem with cycling or extraction, but feeding was an issue, though the gun did better as it wore in. I noted to him that the centerline of the fat Beowulf cartridge is well below that of a 7.62x39, meaning the feed ramp "looks" higher to the cartridge if the feed lips are in the same spot. Also, the rebated rim has less engagement for the foot of the bolt as it sweeps forward, and that if the magazine and trunnion aren't perfectly aligned, the side of the cartridge might drag heavily on a locking lug; on my trunnion, the cartridge wouldn't even pass through the locking lugs without grinding some off.

I also did some searching on .50 Beowulf magazines and feed issues. There's a lot more stuff out there than when I started this project. (Yay! Procrastination! Go!... or, er, no go...) It turns out that there have been issues even with Alexander Arms' own rifles and magazines. At one time AA claimed the Beowulf would feed (this is all AR stuff) from an unmodified AR mag, then that it would only feed through their special mag. And there have been a number of variants of their mags, with different followers and feed lip configurations. I decided to buy a current AA mag to see for myself.

The best price+shipping turned out to be a 7-round mag, which is a 20-round .223 shell. The follower has a little half-.223 molded into the bottom, and as far as I can tell, is a standard .223 part. My only AR mag is out in the shop so I can't compare the feed lips yet. The front of the mag has "50 BW AA" stamped into it.

I have one of the Canis snap-in magwell adapters, so I'll use whichever flat it fits best and be done with it. A few people have suggested cutting up an 80% AR lower to make something like Canis' fancy magwell, which sounds like a smashing idea for later. I want to make sure the mag height and feed angle work out right first.

Finally, I found the original Tapco Yugo flat I started with, that slipped and bent crooked. Examining it with the calipers, the difference in left/right side heights is about .005"; no problem in AK terms. One side is bent almost at 90 degrees, the other more like 70, which makes it look really bad... but apparently it started straight. I think it can be salvaged.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top