Big bore AR.

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g-man
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Big bore AR.

Post by g-man »

Have been planning this for a while, but finally started the ball rolling: BCG, barrel, and gas block swap on my 7.5” barreled AR pistol for one of the big-bore options. Found a 10.5” 12.7x42 barrel at a recent ELGS, so I snagged a gas block from Sportsman’s Guide (along with a bunch of 9mm JHP), a type II Grendel BCG from Bear Creek, and a cheap compensator off Ebay to complete the package. I know I could have just gone with a Grendel bolt, but when Bear Creek had a whole BCG in stock for what some other places wanted to back order a bolt… easy decision.

Still waiting on FEDEX for the BCG and comp, but come Monday I should have a functional .50 Beowulf pistol. The bore on this thing is cartoonish, and I imagine it will only get better with the comp in place. Going to take a couple of my GI mags and Dremel the front edge into a feed ramp, and I’ll have some 10rd mags. Got the barrel swapped, so the last few pieces should be a quick install.

ETA: Pics once she’s all gussied up. I know, pics or it didn’t happen, but it’s not done happening yet.
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tfbncc
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Re: Big bore AR.

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HTRN
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Re: Big bore AR.

Post by HTRN »

I hope you bought magazines - Beowulf won't function right in 223 mags.
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g-man
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Re: Big bore AR.

Post by g-man »

As I understand it, I need to have non-tilting followers, and have to grind a feed ramp into the front edge of the mags for them to feed. Also, I have to open the ejection port up from .495", since it should be readily apparent to anyone who can math that a case large enough to accept a .500 projectile may on occasion have a difficult time leaving the firearm through the aforementioned stock port.

BCG came in yesterday, so I sorted the ejection port and set up one magazine. Cycles through a mag's worth of ammo fine via the charging handle, so the last piece I'm waiting on is the compensator.
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HTRN
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Re: Big bore AR.

Post by HTRN »

g-man wrote: Sun Dec 05, 2021 3:20 pm Also, I have to open the ejection port up from .495", since it should be readily apparent to anyone who can math that a case large enough to accept a .500 projectile may on occasion have a difficult time leaving the firearm through the aforementioned stock port.
Or you can buy a enlarged port upper.

https://tromix.com/product/big-bore-bil ... -receiver/

:ugeek: :mrgreen:
HTRN, I would tell you that you are an evil fucker, but you probably get that a lot ~ Netpackrat

Describing what HTRN does as "antics" is like describing the wreck of the Titanic as "a minor boating incident" ~ First Shirt
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g-man
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Re: Big bore AR.

Post by g-man »

Oooh, pretty. However, the application of a Dremel to the upper I already have proved A: Quick and easy, and B: Free (more importantly). I will have to keep those in mind should I fall down the .450 Bushmaster rabbit hole as well.

Image

Yes, I know BUIS should also be a thing... but as it stands it'll run. We'll see how quickly it gets warm holding in front of the angled foregrip right over top of the gas block. Pulled the Sightmark off my AR rifle when I finished this build in .223, and now I'm definitely not worried about putting any significantly better optics on it. But at least BUIS will be a thing.
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Vonz90
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Re: Big bore AR.

Post by Vonz90 »

Very cool. I have sometimes considered a 458 SOCOM build. The 50 Beowulf doesn't interest me for whatever reason.
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Netpackrat
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Re: Big bore AR.

Post by Netpackrat »

That angled foregrip is a little too vertical at the end for me to be comfortable having it on my pistol. On my AR pistol, all I have is a little nub of a finger stop from Arisaka that would be difficult to construe as a grip of any kind.

https://arisakadefense.com/finger-stop-m-lok/

Also, keymod sucks except maybe for grocery store shelving.
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HTRN
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Re: Big bore AR.

Post by HTRN »

Netpackrat wrote: Wed Dec 08, 2021 5:58 am Also, keymod sucks except maybe for grocery store shelving.
Pallet racking.
HTRN, I would tell you that you are an evil fucker, but you probably get that a lot ~ Netpackrat

Describing what HTRN does as "antics" is like describing the wreck of the Titanic as "a minor boating incident" ~ First Shirt
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g-man
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Re: Big bore AR.

Post by g-man »

Vonz90 wrote: Wed Dec 08, 2021 1:57 am ... The 50 Beowulf doesn't interest me for whatever reason.
I was back and forth between the two, and found a good deal on a 12.7x42 barrel. Both can handle bullet weights up to 600gr, which is what I want to end up loading to just subsonic levels for suppressed pig thumping. I figured if the limiting factor is the speed of sound, I'd at least max out the size of the wheel weights I'm chucking downrange. .458 has some advantages there for bullet selection since it shares a bore size with .45-70 and a bunch of other stuff, but for the volume of rounds I'd load, I'm not terribly concerned. Plus, it's fun to say "I have a .50-cal pistol...".

Netpackrat wrote: Wed Dec 08, 2021 5:58 am That angled foregrip is a little too vertical at the end for me to be comfortable having it on my pistol. On my AR pistol, all I have is a little nub of a finger stop from Arisaka that would be difficult to construe as a grip of any kind.

https://arisakadefense.com/finger-stop-m-lok/

Also, keymod sucks except maybe for grocery store shelving.
Yeah, but yours is totally vertical... [/snark]

I like how light the keymod hand guard is, but agree that it's pretty much junk for attachments. I have another hand stop on order, and I'll just swap this one back over to my rifle. I should probably put a longer hand guard on this thing at some point so I have somewhere to grab up front that isn't right over top of the gas block. That's the great part about ARs... you can just keep modding it until it's right where you want it to be.
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