Deciding on an AR10 caliber..

[44caliberkid]

I did a search of info on 300 WSM AR's awhile back and the consensus was they don't work very well.

[stagpanther]

Hey Stagpanther.
I am going to build a 358 upper for an AR and maybe a 338 Federal. In the past I have used metal mags for customers, but I was thinking of using the Mag pull 10 round mag and I am going to use a scallop file to slim down the inner ribs about .040" per side to give better clearance to the case necks where they brace up against the shoulders of the cartridges.
Have you done the same?

In either the 338 or the 358 I believe very good ballistics can be achieved in a shorter barrel because of the room we have to burn powder. My customer wants a 16" and I see no real reason to argue for anything longer. In the 338 Fed I may stick with a 20" or go to an 18"

So my 2nd question for you is in your builds what barrel lengths did you used and did you do any chronographing of the loads?

Please let me know.

AR10 type rifles are not all that popular here in Wyoming and I have suggested the 358 to several people in the past because we have a lot of elk and grizzly bears, but for whatever reason the 2 calibers have not caught on with the auto shooters as much as I would have expected.

I make my own barrels and for a while I made my own handguards and gas tubes because I have found the issue with reliability that was an issue with the 308s and all smaller calibers was more related to port location than most other factors. In the 338s and the 358s it was not a problem because the powder has more room to burn. So I have used standard length tubes and standard barrel dimensions on my 338s and 358s so far, but I have not done the short carbine length on them yet, so this is an area I'd love to talk over with those that have.

Anyway, if you would not mind "talking shop" a bit, please get in touch with me

Since I have spare time on my hands during home-quarantine, I'm going to whip up a batch of 358 win cartridges and get some data for you. : ) Just discovered I don't have enough 225 GK's on hand so I'll have to use 200 interlocs.

[stagpanther]

Two moderate power loads (47.7 and 48.1) which both put 3 shots sub-MOA and one flier. Gun is slightly out of tune since I haven't fired it in a long time. Powder is AA2520. For some odd reason KAK's own bolt was having intermittent issues going fully locked up, I swapped out another carrier group and everything functioned fine.

[kilotanker22]

Even though I love my 6.5 Creedmoor rifles, my choice for a semi auto battle rifle would be .308. reason being that 7.62 ball ammo is everywhere and usually dirt cheap. It is also accurate enough to engage man sized targets at 500 yards.

Hunting ammo is also plentiful. Plus out to 400 or so the 308 has a little more energy. And the larger bullet diameter will generally leave a wider wound channel. Although the 6.5 will probably out penetrate the 308