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.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.
 
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#118 ·
Thanks for the pointer; I just spent half an hour trying to find that thread. For whatever demented reason no combination of .500 and S&W would bring it up.

Time to inventory my tooling and see what else needs to be on the order...
 
#119 ·
you could build the Gas Block along with making or modifying the RSB to fit the big diamiter barrel. that stuff will all be the same regardless of chamber size. is this going to have a front sight or are you going to just use optics?


so did you find the pictures of the 500 S&W???
 
#120 ·
>you could build the Gas Block along with making or
>modifying the RSB to fit the big diamiter barrel. that stuff
>will all be the same regardless of chamber size.

Right.

> is this going to have a front sight or are you going to just
> use optics?

The plan is to use iron sights; I'll make a rear sight for the top cover and a new front sight at the end of the barrel.


> so did you find the pictures of the 500 S&W?

Yes. Too bad he only had pictures of it all dressed...
 
#121 ·
Alexander Arms says their Beowulf barrels are .980 "under the handguard" and .906 at the gas block. I haven't seen a picture to see how far the .980 diameter extends.

For the muzzle end, Dunlap's gunsmithing handbook recommends .150" wall thickness at the muzzle for most sporting barrels. I'll have to decide how I want to extend the end of the barrel... right now, I'm leaning toward just turning a step on the end, sliding a brake over, and silver soldering.

Gharr! No use working on the barrel until I get it chambered. Can't chamber without a reamer. Can't order the reamer until I get some brass. Which has been back-ordered for six weeks already...

"You are in a maze of twisty little passages, all alike."
 
#122 ·
Gharr! No use working on the barrel until I get it chambered. Can't chamber without a reamer. Can't order the reamer until I get some brass. Which has been back-ordered for six weeks already...
you can do every part of the barrel and the build except chamber it right now.

you are going to need to determine bolt clearance and extractor groove clearance before you can cut the chamber. the way I do mine is cut the extractor groove and turn the the shank (in your case turn the shank and cut the threads ) and set the barrel in the trunion at the correct depth to give the proper bolt to breach clearance. once I know thats right I chamber it with the trunion on the barrel. I have done it seprate of the trunion but it ads a few more steps I also have short chamberd them and then hand reamed it to final head space depth as well.

you already know how thick the shank and thread size needs to be you also can now determine the dia of the barrel were the RSB,GB, hand guard retainers if your using them, FSB, ect as well as all the work for the brake can be done. 95% of the gun can be built with out the reamer. Id do it as a screw build leaving the holes the original diamiter so you can get all the bugs worked out with the feed ramp/bullet guide with out the reciver attached. if you go screw build initaly the entire gun minus the chambering can be built now and then the trunion can simply be unscrewed the barrel /trunion asssembly reamed for the chamber and reinstalled. once the bugs are worked out the barrel can be pulled and a rivet job can be performed.

keep in mind that with a screw in barrel build the rsb needs to be removed or at least slid back to un screw the barrel. on my varmit build stuff I press the barrrel from the breach end.

IMOO your barrel purchase dictates that your going to build some sort of 50 cal AK if the beowulf brass dont come through you can still have the gun built 99% and go with a 500 S&W or some other wild cat still
 
#123 ·
> you can do every part of the barrel and the build except
> chamber it right now.

I could, but I've never used a chambering reamer before, so I'm a bit cautious. The rest is basic machine work, no problem.

> you are going to need to determine bolt clearance and
> extractor groove clearance before you can cut the chamber.

From what I've seen the Beowulf case head sticks out of an AR barrel quite a bit; it goes in until the step at the rebate, with the head sticking out rather far. Though I guess there would be no problem with pushing the case in as far as the extractor would allow. In fact, that would allow for grinding a ramp in the barrel if necessary.


> IMOO your barrel purchase dictates that your going to build
> some sort of 50 cal AK if the beowulf brass dont come
> through you can still have the gun built 99% and go with a
> 500 S&W or some other wild cat still

<grumble>
 
#124 ·
The case should stick out about the same amount as a 7.62x39 round does. your bolt clearance needs to be he same as a 7.62x39 as well.

the bolt clearance if the same dictates how deep you need to set the chamber.

id turn the barrel for the gb and the rsb ect as well at get the treads on the trunion figured out. Id thread the barrel and screw it in to the correct bolt clearance. once the barrel is proberly threaded I would do my chambering and when its close on the lathe id reinstall the barrel and ream the chamber the last few thousands by hand. if you screw up and go to deep simply turn off the shoulder that hits the trunion and reset every thing. Id be more worried about cutting the threads on the trunion and the barrel than chambering it. its pretty hard to screw it up. you are likely going to have to screw and unscrew the barrel loose from the trunion a few times.

if it were mine id turn the profile and threads set the barrel into the trunion and set bolt clearance then you know were the extractor groove needs to be becuse the barrel is now set. Id then remove the barrel cut the extractor groove and then reinstall YOu could short ream at this point but Id just do it with the trunion installed on the barrel that way you can simply just install the go an no guages as you ream.

I like the idea of seting the chamber as deep as possable to be able to cut more of afeed ramp. the 410 Saiga has a guide built into the barrel hanging over the top of the chamber. this may be nessacery here as well.
 
#125 ·
update

Nothing from the ATF yet, but I have a Yugo flat and a couple of trunnions.

Brass still on back order from Impact; got email from them last week.

Bullet mould still on back order from Lee, just called them on the phone.


Well, I needed some time to build a trailer for the drag bike anyway...
 
#128 ·
status and ATF reply

Still no brass, still no bullet mould. I've managed to collect some more small parts.

I got a call back from the ATF. I was in traffic and pulled off the freeway into a parking lot and had a long conversation with the guy, who was friendly enough. I missed his name at the start and forgot to ask it again. He said that a ruling had made the "3 hole" receivers NFA parts, and that I should turn it in to any local law enforcement agency or the nearest ATF office. I told him I'd prefer to demill it and salvage the front and rear sections to build a new receiver. He told me he'd mail a drawing and instructions and his card in case I had any other questions. I asked if they wanted the cut-out receiver sections as proof the cuts had been made, and he said no, they'd take my word for it.

A week or so later an envelope showed up with only a generic "US Department of Justice" return address and a single sheet of paper, no name, cover letter, or card.

The paper was a side view of a stamped AMD-65 showing three cuts across the receiver, which must be done with a torch making a minimum of 1/4" wide cut.

The cuts are to be:

1: in front across the middle rivet area, severing the locking lugs from the front of the trunnion

2: across the "third hole" in the middle of the receiver

3: diagonally across the rear trunnion

I hope there was some confusion between "demill" and "destroy" during our conversation...

I'm assuming the guy I talked to was the one I spoke with a couple of months ago, so I'm sending him another letter asking for a clarification.
 
#129 ·
I recently received a couple of the cut up milled Yugo receivers from APEX. The first thing I noticed is that the barrel pin protruded quite a bit LESS into the barrel on the milled trunnion. On a stamped yugo trunnion the pin cuts approx .140 into the chamber/ breech area of the barrel& on the milled trunnion it's more like .102. So about forty thousandth less than a stamped trunnion. A re-welded milled receiver may be a better choice for the Beowolf ???
I have about a dozen boxes of ammo from Cabelas, but it looks like they no longer carry it.

Brad
 
#130 ·
Jrstang had the same idea I am going to use on my next 500 style AK build. The RPK gas block is roughly .800 depending if it's Yugo(bigger) or Romy(smaller) by a few thou. I've enjoyed reading this post. Hey hunter 1BG, I bagged a Javelina with @ 131 yds (1S1K) with the Saiga 500 S&W last season. My machine time has been severly hampered by a couple of numnuts screwing all personal projects on the job, after hours for the last 8 months. Mr jrstang beat me out (akforum) and snagged a couple of shorten RPK front ends for $60 each shipped (he was first). Heck I just wanted one! Those RPK gas block and rsb are hard to come by and mucho $. Heads up.... RGUNS has new Yugo RPK GB @$55, RSB@$35 and VIRGIN rpk TRUNNIONs@$45 s&h is $15. FSB are all small dia so you might have roll your own. Good luck on your build. Willie
 
#131 ·
> A re-welded milled receiver may be a better choice for the Beowolf ???

That's Plan A, using the Chinese milled receiver I have.


>I have about a dozen boxes of ammo from Cabelas, but it
> looks like they no longer carry it.

You have some Beowulf ammo? Would you be willing to sell me one or two cartridges, or even empties?
 
#133 ·
#136 ·
If you need another USA 922r part take a look at the trigger guards @ K-var. You will have to piece it togather. Trigger guard ($4.50), EG mag catch(4.95), Bul mag pivot pin (2.00?) and spring (1.50?) But no selector stop. They have a great price on Stock sets. US butt & pistol grip w/Bulg front all syn for $39.95. Sale ends this weekend. I haven't used a Weiger mag but am sure it's close to the Norinco mag I modded for my 500 build. Put some aluminum stock to support the inside of the follower, clamped it in a vise and ball peened the center. Ended up with a nice radius center feeding mag.
 
#141 ·
Well 1BG can give you a ton of excuses but the main one is " I can't use the machines after work any more". Two other kids at work screwed up by fighting about toys (car puss and motorcycle wuss). Boss said NO more personal work period. All this went down about 8 months ago and Myself and a hand full of others got screwed cuz of the wuss & puss. I have a buddy that will let me use his machines but he has a business and it's super pain to to to over there and work around his schedule without taking advantage of his friendship. So I have two .500 barrel blanks, two 410 Saiga bolts and carriers (got em from Dinzag) , 100 NEW 338 Ultra Mag cases and a bunch of other parts in limbo. I have kept busy with some "normal" AK/RPK projects and hunting season is about to start. I'll be chasing birds next weekend. Noticed some of your projects on a couple of sites. I respect your being able to "Think outside the box mentality", understanding of mechanical principles and pride in quality workmanship.
 
#142 ·
Well 1BG can give you a ton of excuses but the main one is " I can't use the machines after work any more". Two other kids at work screwed up by fighting about toys (car puss and motorcycle wuss). Boss said NO more personal work period. All this went down about 8 months ago and Myself and a hand full of others got screwed cuz of the wuss & puss. I have a buddy that will let me use his machines but he has a business and it's super pain to to to over there and work around his schedule without taking advantage of his friendship. So I have two .500 barrel blanks, two 410 Saiga bolts and carriers (got em from Dinzag) , 100 NEW 338 Ultra Mag cases and a bunch of other parts in limbo. I have kept busy with some "normal" AK/RPK projects and hunting season is about to start. I'll be chasing birds next weekend. Noticed some of your projects on a couple of sites. I respect your being able to "Think outside the box mentality", understanding of mechanical principles and pride in quality workmanship.
Man that is a damm shame that a couple idiots wreaked it for every one. The 500 S&W you built was IMOO one of the most interesting builds I have seen on the boards. I have some machinery but My skills are not any were near profesional. I never have a enough tooling to do what I want. Im kicking around taking a machine shop cource at the trade colledge while im not working. I hear the head instructor is very pro gun. I have a 50 BMG barrel That Id like to build a reciver for but Im only going to do it if Im confident it temperd right and safe. I hope you find a way to carry on your projects as Im sure that wildcat would be a awsome build.
 
#143 ·
Brad sent me a couple of loaded Beowulf cartridges. I dropped everything to play with them.

They snap tightly into a 7.62 bolt. Good.

They can be forced into a military M-16 magazine, but the case mouth catches on the front of the magazine. You can force the cartridge out, but properly, either the lips need to be tweaked, or a bit of clearance needs to be ground into the front of the magazine. Alexander Arms' web site said the mags needed to be tweaked for the Beowulf, but a lot of people reported they'd had no trouble with unmodified mags. Variation between manufacturers, probably.

I just ordered a couple of G3 mags from CheaperThanDirt for 99 cents each, and an M-14 mag for $11.97. They didn't appear to have any FAL mags. From the pictures it looks like the M-14 mags might be easiest to work with.

The other option would be to cut the top off a 7.62 AK magazine and make my own mag body. I'll see how much worth it will take to adapt something else first, though.

They will fit into a 7.62 AK magazine, but they have exactly the same problem with the case mouth hitting the front; same solution, I suppose.

If you hold the follower down and get the angle just right, you can cram them into a 5.45 AK magazine. The lips need to be widened a lot. I also discovered the width between the lips is narrower than a 7.62; the 7.62 bolt is wider than the 5.45 lips, which means the 5.45 bolt is narrower across the bottom. You guys probably all knew that already.

I think I could get three, maybe four Beowulfs (Beowolves?) into a 10-round 7.62 magazine and they'd feed OK. For a 30-rounder, I might get a couple more, but the follower would be at a pretty sharp angle by then due to the curvature of the magazine. I bought the 5.45 mag because it was straighter than the 7.62; it looks like it would hold 7 or 8 rounds okay.

I'd planned on picking up a couple more 5/10 round mags anyway, so that's no problem.

For a larger mag, there's the magwell adapter fangle to use AR mags, or modifying 5.45 mags.
 
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