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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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#177 ·
Now I'm pondering buying a milled Yugo receiver without barrel pin hole, from Scott at DPH. I'm thinking of relocating the pin slightly higher & maybe slightly smaller. To gain chamber clearance. Could even put a second smaller pin on the bottom.
I want pressed in barrel. Threading barrel & timing the Headspace & extractor groove & gas port, etc. would give me a headache.

Worth a try????

Brad.
 
#179 ·
Please elaborate TRX. Were you thinking of slightly re-locating pin also? Or threading barrel since your a machine master? I know the magwell will be a tad wide, but I was thinking of adding shims to both sides of my Romanian .223 mags, rather than messing with magwell mods.
did we have same thought same time???
 
#182 ·
I'm going to press and pin the barrel. I have one of the virgin Yugo trunnions, which should make it easy.

If I was having to start with a threaded trunnion I'd probably bore it smooth and pin it.

Timing the gas ports on a threaded setup isn't all that bad - just torque the barrel in place a few times to make sure the threads are all mated up, put a witness mark on, and then line up on that - but press and pin is way easier. It's one of the things I expressly like about the AK.

Using a pressed trunnion that already has a pin hole makes things a lot harder. The most reasonable solution for that is to thread the trunnion. wttool.com has the proper tap for $30-ish, which is amazingly cheap, but tapping hard steel like a trunnion can be iffy. If you cut internal threads on the lathe, you might want to press a sacrificial pin in first, bore it flush with the ID, and then thread across is. The threading tool will tend to deflect going across the interruption of the empty pin slot, which can cause troubles, particularly with a light duty lathe like mine.

Hmm... looking at my Yugo trunnion while I'm typing this, I just had another idea. Back in the main AK section I posted some pictures of stamped Valmets; one of them used a rivet instead of a plain barrel pin, since the Valmet's upswept receiver front is missing the place where the lower rivet would go. So they made the barrel pin take the place of the lower rivet.

It looks like there's room to open up the lower-front rivet hole in the Yugo trunnion. You'd have to offset it up a bit. For a garage shop, you could carefully egg the hole up with a carbide burr in a Dremel until it intersects the barrel, then make the hole round with a drill and reamer.

Again, while drilling and reaming, a piece of scrap steel or old barrel stub pressed into the trunnion would help a lot. Ideally the hardness should be the same as the trunnion to keep the bits from wandering, but even softer metal would be better than nothing.

Then just rivet the front of the trunnion as usual.
 
#183 ·
The .223 mag from Apex showed up today.

Well, well, well, my droogies...

The two Beowulf cartridges I have slide neatly in and out under the feed lips. It really needs a slight notch at the front to keep from snagging the case mouth, but so goes the USGI M-16 mag I have.

I hadn't started making the magwell. Now I guess there's no reason to start.

Crazy thing is, the 5.45 magazine isn't even *close*; it requires grinding all over the place to feed a Beowulf. Stand a 5.45 and a 5.56 side by side, and other than the shoulder distance, there's f-all difference between them.
 
#185 ·
It's a virgin trunnion, so I'm going to press it together at .002" interference, then drill for a pin.

The bore in my Yugo trunnion is .906, and a 15/16-32 tap has a minor diameter of .907, which is darned near perfect. wttool.com has the tap for $22.
 
#186 ·
The bore in my Yugo trunnion is .906, and a 15/16-32 tap has a minor diameter of .907, which is darned near perfect. wttool.com has the tap for $22.
Interesting I have been debating on thread size on the switch barrel build Im pretty sure 1-12 will be fine in a yugo trunion but with the all the voids and hollows of a Rommy I want all the thread engagement I can get. Its not very hard to bore a trunion mine cit really easy. I made a set up guage that chucks into the mill that when it slides up and down in the clamoed in trunion with no interferance its good to bore. I use the same tool to set up for truing the bolt and truing the face.

So you plan to just drill the barel pin hole higher to allow the pin to clear the chamber ???
 
#189 ·
Well, come on in, the water's fine!

My build went on the back burner when Beowulf ammunition went away, but I just found out Starline is shipping Beowulf brass again. I need to call Alexander Arms and Impact and check on the status of my orders (which have been back-ordered for a year now), and see if they'll honor the original price. If not, I'll cancel and order directly from Starline.
 
#191 ·
Had a bunch of other stuff going on, didn't jump right on the Starline brass, and it's out of stock again. However, a little box showed up today from Alexander Arms with a bag full of Beowulf brass in it. Maybe the other from Impact will show up sometime soon.

13 months, 5 days since I ordered. Well, at least they showed up...

I've started on a .410, a 2XTM, and the Hadar since then, but now I guess I need to get back onto the Beowulf, particularly now that I can replace the Tapco flat with one of the new AK-Builder flats.
 
#193 ·
When I started the build every sizeable vendor had Beowulf brass, mostly in the 55 cent range. It was even cheaper than .45-70 or good 54R brass. That's one of the reasons I went for the Beowulf.

Being unable to predict the future, I wasn't able to know that just a month later Beowulf brass would be *GONE*.

Another reason I went with the Beowulf was that the .499 wossname and the .458 SOCOM were "out of stock - no backorder" everywhere, while everyone claimed they had Beowulf in stock.
 
#194 ·
O-kaay! Brass finally showed up from AA, and then a week later Impact said they were shipping, too. After hugging the plastic bag full of brass to my body and making crooning sounds for a while, I went out to the shop to chamber the barrel.

Arg. The Green Mountain barrel is just enough smaller than spec across the lands that the Pacific reamer pilot won't clear the rifling. I sent Pacific the specs from Green Mountain's web site, so it's not their fault.

Fortunately the reamer uses a removable pilot. I'll have to make one on the lathe.

Anyway, the Beowulf project is up and rolling again!
 
#195 ·
midway has beowulf ar15 barrels now, you could lathe off the locking lugs and it would work for this project.

AR-Stoner AR-15 Barrel and Bolt 50 Beowulf 1 in 20" Twist 18" Stainless Steel - MidwayUSA

:cheers:

The bug bit me again, so I've been daydreaming.

458 socom bull barrels are available here.

.458 Socom Barrel (Heavy) - $395.00 : MGI Military, MGI Military

I was thinking, I have a junk trunnion, I can cut it up and use it as a sleeve to weld the rear sight block to.

A custom gas block is really not that big of a deal, a machine shop could do the hard part pretty quick, you just need a square block with two holes bored into it, you can drill the third hole (gas port) your self.

A virgin trunnion would be usefull so you could choose the exact location of your barrel pin. threading it is a good idea too, just harder to head space.

Any respectable machine shop should be able to make a "gas block" (aka manifold) in a few minutes. Probably for less money that it would cost you to buy the drill bits to make it yourself. drilling out an fal is a good idea, I don't know if there is enough metal there though. and the drill bit will cost you $$$

The gas block doesn't need to be fancy. just two big holes and a smaller one intersecting on a square block of steel.

They have those 12 gauge saiga quad rails now, that would go real nice together on this project.

I Oklahoma just legalized night time pig hunting, woot. need those tacktikoolaid rails and all that.
:headbang:

BArrelless romy kits are 129 on gunbroker right now too. looking at sub $1000 to put this whole thing together, and have the coolest ak on the block.
 
#197 ·
HMMMM you should be able to build the gun way less than $1000. there is not much differant than any other build. use standrd parts other then the barrel and some PSL parts. the gun should be doable for around $45o or so depending on what barrel blank you start with. I sure would not start with a AR barrel id just get the right blank or doner take off and then chamber it. keep in mind you are not going to be able to just pin in the barrel as it will it the chamber.
 
#198 ·
HMMMM you should be able to build the gun way less than $1000. there is not much differant than any other build. use standrd parts other then the barrel and some PSL parts. the gun should be doable for around $45o or so depending on what barrel blank you start with. I sure would not start with a AR barrel id just get the right blank or doner take off and then chamber it. keep in mind you are not going to be able to just pin in the barrel as it will hit the chamber.
 
#199 ·
O-kaay! I have a box full of (well, with four) AK-Builder Yugo fixed-stock flats, I finished the Yugo bending shoe for the fixture, and I'm almost finished with the oil catch pan for the lathe. I need to order a pump for the oiler - I'm going to oil through the barrel while reaming. I know most people don't, but "there's no kill like an overkill", and after what I spent having a custom reamer made, I'm taking no chances.

My lathe's tailstock doesn't have enough travel to ream the chamber. I found a stripped tailstock casting on eBay to make a lever-operated tailstock from. Fortunately I don't need graduations or a Morse taper on the ram; it just has to hold the reamer head.

Both barrels are too small for the reamer pilot to fit into, or vice versa. I still need to call Kiff and get a couple more pilot bushings.
 
#200 ·
run your lath slow and feed the the reamer by hand with just a tap ahndel or simular tool and a pretty decent chamber can be cut with out using a tail stock. there is really no need to run coolant through the barrel or any thing like that just pull it out every 15 seconds and blow it off and reoil it. Chips getting caught would be my biggest fear.

back in the old days before floating reamer holders and all that, lots of chambers were cut by hand held reamers and turning the barrel in a lathe. Id go hand held over a fixed set up any day unless your lathe is very very accurate and you can get that bore perfectly true and lined up tot he spindel. If you think about it a floating reamer holder really dont do any thing you cant do by just holding it by hand. the main thing is go slow and have a pilot that fits right. Ive done several recuts were I deepend the chamber slighty with just the wrench that fits my tool post. JUST GO SLOW.
 
#201 ·
"I hear what you're saying." I know you've chambered a bunch of barrels, and if I run out of time or patience, I'll do as you suggest.

I have a bunch of gun and non-gun projects running in parallel, and while the lathe oiler is a project in itself, I also need it for some other work. So if I can arrange things to have the oiler available while I'm chambering, I'll get some real use out of the thing, rather than using it for a couple of projects and then pushing it aside out of annoyance for the next ten years.

I'm queued up to chamber two Beowulf barrels, two .311 Whisper barrels, a 6.5 Ross barrel, a 9mm barrel, a .30 Gibbs barrel, a .311 Whisper* sizing die and a case forming die, a 6.5 Ross** case forming die, a .30 Gibbs sizing die and hydraulic forming die, and probably some other stuff I don't remember offhand. So I'll get *some* use out of the oiler, anyway.

Remember, "There's no kill like an overkill."



* Since SSK is pretty aggressive about their rights to the "Whisper" name, I really need to come up with another name for that wildcat, but ".311 I-Did-My-Own-Wildcat-Ha-Ha-Ha" just seemed a little... awkward, somehow...

** This one is technically a wildcat, since it involves reforming a rimmed .303 British case to fit into a shortened 6.5 Mannlicher (rimless) die and chamber, but it's so trivial I can't take any credit for it. At a loss for a name that didn't sound like total dorkage, I remembered the Ross rifle company had chambered some of their MkIIs in 6.5 Mannlicher, and then they'd come up with their own ".280 Ross", so I named it "in honor of" them, like the many "Whelen" cartridges that have no actual connection to Townsend Whelen.
 
#202 ·
When I built my bending fixture I made sure the threaded rods cleared the available space in both the AKM and Yugo flats. I had one of the last Tapco Yugo flats on hand.

When AK-Builder came out with their flats I decided to use the Tapco flat for the test build and just ignore all the unwanted underfolder holes.

When I checked the AK-builder flat I ran into a problem - the pistol grip hole was smaller than the 3/8" all-thread, plus it was offset maybe 1/8" from the Tapco. Which means I can't run my pullrod into that hole.

The big hole in the Tapco flat looks just like the one in my Romanian flat. A Romanian grip nut fits. I'm guessing the Tapco one is designed for something riveted on.

Also note the substantial differences in the carrier cutouts and miscellaneous holes.
 

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