I am building a replica of a gun from a video game. The gun will end up looking like a retro dissipator, and be chambered in 50 beowulf. I believe I have secured the unobtanium part to make the build (an A2 style sight base with a .936 journal) so the build is possible.

What I'm having trouble coming up with is a barrel. I've found several sources of "cheap" barrels that will fit the bill, such as Bear Creek, Midway AR-Stoner, Moriarti etc. I'm a bit concerned about the reliability and accuracy of a "cheap" barrel. I was hoping Tromix made one, but it appears they only make the slightly smaller calibers like 458 SOCOM and 450 bushmaster. I may yet still choose 458 SOCOM instead at least isolate the barrel and bolt as a problem. Is there a "go to" barrel that people go with for 50 Beowulf? Also, what is the best bolt to go with? If I interpreted what I read correctly, the bolt is identical to a 7.62x39 or 6.5 Grendel bolt, but the extractor is different.

Lastly, I am hoping to make two loads, ideally of the same weight shooting to the same point of aim; a plinker load, and a hunting load. Probably in the neighborhood of 300 grains. I could use advice on bullets. I'm hoping to eventually hunt some deer (100-125 yard max range) with it. In a former life I was an avid muzzle loader elk hunter, so I know the drill with giant projectiles with howitzer trajectories.

ETA: this is what I'm going for.

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All things Beowulf

Expect trouble mixing and matching stuff when it comes to big bore AR's.

No so much "big bore" AR-15's, but large frame AR's can be troublesome.

TROMIX and .458S is what I’d go for.  TROMIX just came out with an “Economy” line of uppers.  It uses first run barrels and BCG but blem upper, CH, and handguard.  They are $550 and test fired for 100% function and come in 10.5”, 12”, and 16”  barrel lengths.
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However, to get that heavy barrel look, the economy line won’t work for you.  You’d have to go with just the barrel and bolt to get the .936 but I don’t think TROMIX does .936 barrels anymore.  You’d need to ask Tony about that.  But you still should go with CAR length gas.  If you are married to that look, you can get Paladin Machine Shop to make your barrel to your exact specs.  He can give you a CAR length .936 gas block journal as well as keeping it .936 all the way to the muzzle so you can use that .936 A2 front sight for the dizzy look.  Contact him at tp555(at)vfemail.net.  He might be able to do the Beowulf (12.7 x 42) but you’ll need to ask him.

That's a nice look .

I have a Bear Creek .458 with just a red dot on it. It’s very accurate out to 75 yards. I haven’t shot it past that distance. But no issues. It takes standard AR mags. A standard AR mag from magpul that holds 30 will reliably hold and chamber 10 rounds. The ammo is more readily an available but is around twice the price of .450 BM or .500 B. Expect to spend $4.5 -$5 per squeeze.

That’s a cool build.  IF you are concerned with looks, Consider a tanker or a pepper pot muzzle break. Both are functional at reducing recoil and look cool.

https://wilsoncombat.com/375-socom-235gr-speer-hc-20-box.html

$2/rd . Good stuff .

- IMO , it should feed a little slicker , shoot a little further , and have better SD in the 200gr range .

I only need the big gas block if I go with 50 Beowulf. If I go with a Tromix 458, I can use a standard .750 on their light weight assuming I could convince them to make a barrel special by skipping the reduced profile forward of the gas block.

Paladin can definitely do that for you.  He did me a .998 diameter 28 13/16” long .458 SOCOM barrel with rifle gas and made me both a clamp on gas block and pic front sight base, both .998 diameter.  He’ll do anything you want so long as it’s safe.

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For what it’s worth, I have a 20” .458 S with a .750 gas block which is under the rifle length handguard and the barrel is .735 in front of the gas block.  I used an ARMS 41BL clamp on folding front sight in front of the forend and it clamped down perfectly on the .735” part of the barrel.

Holy mother of God that's cool. I don't want to divert this threat because it's actually a great topic to discuss, but damn, that's awesome!

Ever run warm side 325gr loads through it? If so what kind of velocities you getting?

325s to compare with because that's all I use in my 16" Tromix upper.

Honestly, the velocities are not much more than a 16”.  With a 250 gr Monoflex I can get right at 1900-2000 fps with a 16”.  That monstrous tube only gives me 2200 fps with the same load on the same day.  Same with 500 gr. bullets even with slower powders.  As so many here like to say, the juice wasn’t worth the squeeze.  IMO a total waste and a 14 pound range toy only.  With that TROMIX brake and at over 14 pounds, what recoil?  

That tube started out as an experimental non-gassed straight pull bolt action.  That was a miserable failure with very sticky extraction with all but light to medium loads.  I had Paladin put in the gas port at the rifle location, not thinking it would work at all since midlength gas often gives problems with fast powders (my 20” with midlength gas will not function perfectly with H110).  If it didn’t work, he could cut it down at the gas port and make me two reasonably length barrels.  The darned thing worked perfectly and has never missed a beat, even with H110.  Go figure?  It is also quite accurate with that almost 1 inch barrel so I can’t bring myself to cut it up.  So a Vernier target sight at the rear and it became my 300 yard Buffalo rife.  My range is only 300 yards but that rear sight can easily go to 500, maybe 700 or 800 yards.  Maybe someday…

But back to the OP, if you can dream it, Paladin can make it.

Just adding some first hand experience to Big-Bores recommendation. Paladin has cut all of my big bores including my 12.7 x 42 which came from a McGowen blank, if I did it again I would just use a Green Mountain.

A  few days after I dropped off the blank, bolt and big bore extension to Thomas I rented the reamer from 4D and had it shipped directly to him. This gave him some time to get the barrel ready for chambering as you only have a seven day window after the reamer has been delivered before it has to be shipped back.

Do your research on the grendel/beo bolt situation, yes the pocket is the same diameter and supposedly AA uses the same bolt with a modified extractor. There is a type 1 and type 2 grendel bolt, one is the standard depth of .125", the other is eleven thou deeper at .136". I can't remember which is which, but I just had Thomas modify a standard 5.56 bolt for my 12.7 x 42 and left it at the standard .125" bolt depth.

He's cut about a half dozen modified 5.56 bolts for me between this, 458 Socom and 50AE- this one is the simplest in terms of extractor modification.

If you can wait until they are back in stock, I agree GM is the way to go.  CroMo or SS blank, 27” long, $123 to $171, long enough to make two barrels, a 16” and an 11 inch, two big bore barrel extensions from TROMIX, a couple of .556 bolts for Paladin to open up, extractors from ?, but I bet they are not too hard to find, and rent the reamer and HS gauges from 4D reamer rental, and Bob’s your uncle.  My guess is you’d have the whole thing done and dusted for under $500 for both barrels and bolts, done exactly the way you want.  The only hard part is waiting for the blank to get back in stock.

The more I think about it, the more I'm considering one of the cheap barrels. The reason being they are parkerized, which helps the look, and they are the correct profile for my sight block.

Are all of the various cheap barrels reached bear creek arms? I've read that most work okay, and that the biggest issues are chatter marks on the feed ramps. I should be able to fix that stuff with cratex wheels.

Finally, I also found satern/liberty barrels. They advertise the wrong profile, but I'm thinking about emailing to ask if they could skip a few turning steps. Their quality reputation and price point are more in line with what I was expecting.

It won’t hurt to ask but don’t get your hopes up.  Most are done on CNC machines so the blank is put in, buttons pushed, and a finished barrel comes out.  Of course I am over simplifying the process but in order to do what you suggest, they’d have to either write a new program (doubtful they’ll do that) or stop the process, which they probably won’t want to do either.  But ask away, the worst is they’ll say no, and maybe they’ll do it or turn it on a manual lathe if work is slow.  Good luck.

Midway just offered me a happy birthday discount. Since it is parkerized, and the right profile, I'm going to risk the cheap barrel for $87 after discount.

Things to figure out.

1) Mill ejection port to fit the Beowulf in such a way that I can still use my ejection port door. Someone sent me pictures showing what to do, but I don't have precise dimensions.
2) Add a feed ramp to the upper to fit the profile of the feed ramp in the barrel.
3) What bolt to buy. I'm still not clear if I should get a 7.62x39 bolt or a 6.5 grendel bolt, and what needs to be done to make it extract. Also am wondering what the best brand is.
4) Magazine modifications.
5) Muzzle device. I'm hoping for something as close to an A1 flash hider as possible. Unfortunately Tromix doesn't their bigbore A1 it in the size I need. I may opt instead for the least ridiculous looking muzzle brake possible.

Mockup of what I have so far. Next step is painting the furniture to look like bakelite. I ordered an H&R C7 upper and some small parts last night. Once I submit my Midway order, I should have a barrel, brass, dies bullets and gas block. All I'll need is the bolt and some powder.

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