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From time to time I get the idea to add a big-bore AR upper to the mix. Something, say, .458 SOCOM or .50 Beowulf. As it will be mated to registered SBR lower, length can be anything.

Recommendations on this one? Other calibers to consider other than the aforementioned? Any to avoid? Thanks.
 
I can't really comment on the two you mentioned as I have not yet owned either. I do however have a 450 bushmaster, that I really like. I did read everything I could find on the 450 and the 458, but ultimately chose the 450b, mainly because I'm cheap, the Bush was much cheaper and I have a ton of bullets already for it. A lot of the posts I read about the two turned into ford-Chevy arguments, so for what I'm planning on using it for, whitetail hunting in reforested timber land, fifty to seventy five yards shots, equipped with red dot sight, either would do. I just finished working up loads for the grendel and 300b, so the Bush is next, but I'm very happy with the accuracy of the hornady 250g flex tip. I enjoy shooting it, it's definitely a thumper, but I don't think you can go wrong with any of the three.
 
I would like to get a .458 socom upper with a 10.5" barrel as I already have a SBR lower and a suppressor.
I've been a 45-70 fan for years and this would be kind of a modern version of the 45-70.
 
I'll be going with a 16" .458 SOCOM complete upper from Tromix.
Home - Tromix Lead Delivery Systems

The .458 SOCOM has a shoulder and headspaces on that shoulder like a rifle cartridge and uses .458 rifle projectiles. The 450 Bushmaster and .50 Beowulf are straight-walled and headspaces on the case mouth like a pistol cartridge and use .452 and .50 pistol projectiles.

Lots of good information on the .458 SOCOM here...
Teppo Jutsu : Advanced Firearms Applications
 
From time to time I get the idea to add a big-bore AR upper to the mix. Something, say, .458 SOCOM or .50 Beowulf. As it will be mated to registered SBR lower, length can be anything.

Recommendations on this one? Other calibers to consider other than the aforementioned? Any to avoid? Thanks.


My recommendation is to get yourself an 80% lower .308 receiver and an AR-10 rifle build kit complete with BCG
 
I'll be going with a 16" .458 SOCOM complete upper from Tromix.
Home - Tromix Lead Delivery Systems

The .458 SOCOM has a shoulder and headspaces on that shoulder like a rifle cartridge and uses .458 rifle projectiles. The 450 Bushmaster and .50 Beowulf are straight-walled and headspaces on the case mouth like a pistol cartridge and use .452 and .50 pistol projectiles.

Lots of good information on the .458 SOCOM here...
Teppo Jutsu : Advanced Firearms Applications

Wow, great info. Thanks for the links!

Had been thinking on .50 beuwulf for a long while, probably will still think on it for some more.

That caliber seems the "easiest" to get started with big bore AR. Same bolt, so less to buy into outrite.

Less accurate further out tho, due to the chambering (case vs shoulder), but what would our actual intended accurate distance for such truly be? Q's I'd need to consider.

No need ATM, just something to think on...
 
375 SOCOM is the one I would do .
This ^^^
I'd do 458 SOCOM or 375 SOCOM
It's a rifle cartridge that has a shoulder to headspace on.
Not a fan of the pistol-ish cartridge solutions for big bore AR.

375 SOCOM
SOCOM375Round_zpsyqth7xcs-660x495.jpg
 
A buddy insisted his new .50 Beowulf was all I needed to make my day.

So I fired a magazine or 2 of his.

YMMV, for me it was unpleasant & inaccurate. Perhaps there are advantages I'd come to love. Eventually.
 
I have a 16" .458 SOCOM upper, and I love it. Takes the boring out of the AR platform for me. It really smacks steel. I am developing loads for it at the moment. I haven't fired the Beowolf or .450 Bushmaster. Since several states legalized hunting with straight walled cartridges, the .450 now has lots of support - much more than .458. It was about dead before then. I have an AR limbsaver pad on mine. Recoil isn't an issue for me with that pad on there, even from a bench. I haven't fired it without the pad. The .458 is a little picky about mags, but I bought lancers and they work fine. I still widened the mag mouth a bit - I also have a 7.62x39 AR and experience with that platform, so I rather the mags have every advantage possible to be reliable.
 
AR shotgun instead? I'm not a huge fan of the big bore AR15s. But a shotgun in the likes of one is definitely interesting. The VR80 by rock island would be my choice over a big bore.

You could also go AR10 and look into the calibers that platform offers for bigbore. They have a rimless 4570 that someone makes for it.
 
You can't look at that, I mean how much are you realistically going to shoot the thing? I'll literally wear out barrels on a 5.56 so I have many, a single .458 SOCOM will last me the rest of my life and then some.

Pony up if you want horsepower out of an AR.

Yep. Go big or go home.
 
For some reason, I keep having these visions in my head of an AR10 set up Mk 18-style and built for .30-06 AP Ball M1... "It turns 'cover' into 'concealment' and it fits in a briefcase. Your move."
 
375 SOCOM is the one I would do .

This ^^^
I'd do 458 SOCOM or 375 SOCOM
It's a rifle cartridge that has a shoulder to headspace on.
Not a fan of the pistol-ish cartridge solutions for big bore AR.

375 SOCOM
View attachment 609426

You guys got that right. I've focused on a clear path to the 458 SOCOM when it comes to the big bore AR, to me the 450BM and 500BF (I'll let y'all come up with the acronym translation ;) ) isn't even on the radar but that ,375 SOCOM does give me a moment of pause. I still think the .458 will ultimately be more "mainstream" and thus support, but damn. I'm hoping/waiting for a .338 SOCOM, that just might be THE sweet spot for a thumper in AR15 frame size,
 
This thread reminds me...

I was poking around the web for the "ultimate" big game hunting cartridge that would fit in standard AR and came across the 7mm Valkyrie AR (7VAR), it's looks a pretty badass performer. Here are some statements from 7mm Valkyrie AR web site...

The 7mm Valkyrie Ar is a full power Wildcat hunting round developed for the AR15. It's goals were to give AR10 performance in the smaller,lighter AR15 chassis.

It is living up to it's design goals. It will push a 140 grain bullet 2700-2850 fps and 168 bullets 2450-2600 fps. Which puts it in the 7mm-08 range of power but still in an AR15.

The Valkyrie was designed by Bruce Finnegan and he was helped in development by a group of like minded guys they called the Founders.

Pressure testing was done with the pressure trace system along with accuracy testing. We have a pet load chart to get guys up and running fast with the Valkyrie.

Brass is made from 6.5x47 lapua it is the best brass to make the cases from. Other 308 cases will work but performance is sacrificed.

The 7mm VALKYRIE was designed to be one of the most powerful hunting rounds for the AR-15 platform. In order to do that the 7mm VALKYRIE uses a proprietary bolt/barrel extension that are sold with the barrel all other standard AR-15 parts are used.

The remainder of the rifle is all standard AR15 rifle components. To be clear, the 7mm VALKYRIE uses standard, readily available AR-15 upper receivers, bolt carriers, buffers, buffer springs, stocks, gas blocks, barrel nuts, hand guards and lower receivers without modification.

The 7mm VALKYRIE works best with 6.8 PRI magazines because they allow 2.31 oal and they are stiffer so they don't bulge when loading. Some of the longer and heavier bullets require an oal of 2.34 inches which requires a notched magazine which will limit capacity to 5 or so rounds. Other 6.8 and 6.5 mags work but capacity is limited because of the mag swelling when loading. Typically around 4 rounds in the asc 6.8 mag and the cproducts 6.5 mag from my testing.


https://www.7mmvalkyrie.com/

There as forum with a bunch of load information, ballistic gel tests, builds and such...

7VAR (7mm Valkyrie) - Modern Sporting Rifle Evolution

I was curious if anyone here has given this round a shot. (Pun intended)
 

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