Heavyweights in the AR-10?

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12 years 9 months ago #10204 by weshowe
Heavyweights in the AR-10? was created by weshowe
Gents,

I use and like 190 gr. SMK's in my M401A1 and it shoots flatter(in my rifle) than 175's or 168's, by a small margin(1/2 MOA) at 600 yards.

I was thinking of trying some in my G.A. Precision 20" AR-10. Since the direct impingment system "meters" the gas pressure I don't see any reason why not. Where's it's a no-no in the M-14 due to op-rod battering, etc.

Anyone running heavyweight bullets in the AR-10?
If you have loads and data it would be helpful.

My load is a 190 Gr. Sierra Match King over 42.2 Gr/IMR-4064, Lapua brass, Fed 210M primer, and an OAL of 2.800". Velocity is 2,608 from my M40A1. The load shoots nominally (1/2 MOA) flatter at 600 yards than my 175 gr loads.

I'd substitute a Winchester LR primer for the Fed 210M. My testing has shown them to be pretty much interchangable.

Your thoughts and experience are solicited.

Wes

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12 years 9 months ago #10210 by foxhunter
Replied by foxhunter on topic Re: Heavyweights in the AR-10?
Can't wait to hear some expert opinion on that, as it seems to me that a 190 gr bullet out of a 308 should be a very good large game round.Anyone have a formula handy to convert Wes' numbers into ft pounds of energy at the muzzle?

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12 years 9 months ago #10211 by foxhunter
Replied by foxhunter on topic Re: Heavyweights in the AR-10?
Found the formula
190gr x 2608ft/sec squared divided by 450400= 2869 ft lb at the muzzle. To compare,
168gr at 2800ft/sec would have a muzzle energy of 2924 ft lb. So I guess it really doesn't make it any better for big game .

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12 years 9 months ago #10213 by weshowe
Replied by weshowe on topic Re: Heavyweights in the AR-10?
Gents,

Thanks for the replies. Theoretically, I suspect the 190 will retain more energy at longer ranges , but will not shoot as flat past 600 yards. It's almost identical to my 175 Gr. SMK load of: 175 Gr. SMK, 44.3 Gr. Varget, Lapua Brass, Federal 210M primer, and an OAL of 2.800" at 2650 FPS.

The real winner may be 155 Gr Lapua. I've yet to try loading some, but have some on hand. Time will tell.

The 190 will do one thing better...buck the wind. Unfortunately, we can't push it hard enough in the .308 to get it to 1,000. Hence the .300 mag...

Wes

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