Fence, choose a side for a new upper. Since Wilson Combat has them both on sale, and I have a few extra M5 Enhanced uppers with handguards, I am straddling said fence. I like a big fat bullet, already have a 458 Socom, but I am wanting large frame AR.

I am leaning 338 Federal only because of factory ammo support.

Both calibers offer about the same weight bullets going almost the same speed. Both are built on a necked up 308 Win case. Knowing that, I'd lean towards the larger diameter bullet of the 358. A 200 grain .358" bullet would be nice!! If you need 358 ammo, let me know. It's an easy and lower cost ammo to make, with lots of good bullet choices.

Hmmm. Neither?

This to be different...
https://winchester.com/350-Legend

Different frame and a large step-down in velocity and energy from the two OP asked about.

I'd go .338, OP, mainly for the reason you gave of factory support. Also, Savage sells that Hog Hunter boltgun in .338 if you ever wanted a companion rifle!

I would go with the .358 Win, but then I am a sucker for that round. One of the cool things about it is that you can load it up with some 158 grain hollow-points and get some good "blow-up" rounds (Plastic jugs, jack-rabbits, yotes, pigs, etc.)

That's on an Ar-15 frame, not an AR-10. And that link with the flashing pictures almost caused me a seizure.



+1!

While our .338 Fed barrels shoot well, the .358 Win barrels usually shoot great. A .358 Win with the Nosler 225gr Partition will kill about anything in North America.

Nope, ain't interested in over hyped anemic ammo

I don’t get any “flashing pictures”...

Then you may want to stop shooting all together...

What length barrel? 16" or 18" on the 358?

What brake for that 11/16" x 24 thread on the 358?

358 Win or 338 Federal with a 200 Grain Accubond would be pretty deadly.

I like 16" if I'm running a suppressor and 18" if not. Threads are 5/8-24 on both .338 and .358

I didn't see a threaded 16" 358 unless it's not on sale

Ranger 16.25" with 5/8-24 threads on sale for $209.95 and in stock

358

Order number 68195812, now get off the internet and go pack it up, load it in the truck and bring a 458 Ham'r along and we'll kill some pigs

Now I need Chad to come up with some tough piggy bullets/loads for it

.358 Winchester. I rebored a Savage Hog Hunter bolt gun and love it. I usually hunt with a .35 Remington but now I have the .358 that's the ticket for me...

The .358 sounds interesting out of an AR Platform.

I'll have to see how it compares to my 45 Raptor slinging 300/gr Hornady XTP's.
I have those at 2150/fps out of a 16.5 barrel.

That is an impressive round, never heard of it before. That exceeds my 450 Marlin shooting the factory Hornady 350gr FP out of a longer barrel.

I just thought a big bore AR10 style rifle would be fun to shoot, my reason for this whole decision. I like large bore rifles.

You will love it. I have a 338 Federal and a 350 Rem Mag bolt action.

Looking forward to your build report.

On one of those Alaska forums I read the .358 win is a popular cartridge among people starting out with a .308 on a budget. You have to use a 200 grain bullet with over 2,000 fpe at 100 yards to take buffalo legally in some regions. Instead of trying to handload 200 grains in .308 to barely make it, and still get the business from a suspicious game warden, you can have a .308 rechambered to .358.

I guess that is popular with meat hunters that want to take advantage of every opportunity.

Well the barrel arrived, but no adjustable gas block, gas tube or thread protector even though UPS says it is here. I have a partial box of ammo to get started.

One thing I am not liking is the fit between the WC barrel extension and the Aero M5 Enhanced upper, way too loose for my liking. Tried the barrel in 3 different uppers, fit was the same in all 3. This isn't the first time that I have seen this, happened with Ballistic Advantage 308 and 6.5 barrels, but the ARP barrel was snug in all 4 I tried it in.

I think this is my last batch of Aero uppers, the AR15 has never been an issue, but it is hit or miss with the LR308 uppers.

I have been "bedding" all the the large frame AR barrels in the uppers using Loctite 620, kind of a nuisance when you pay what you pay for the 308 platform parts.