Long Range Caliber for AR Platform

Ben64 · April 8, 2020, 01:53 PM

Hello All;

I have been doing a lot of reading on the net about choosing the right caliber with a lot of contradictions and... I am more confused now.

I am planning to build a long range precision AR rifle which will be solely used for targets and not hunting; I gave up hunting a long time ago. I would rather stay with the smaller frame AR15 but that is not a deal breaker. I know there are DPMS 308 Gen II which are smaller frame and POF Revolution AR10 which is the same size as AR15 (I don't like it since it is proprietary).

lots of people are recommending 6.5 Creedmoor which fit AR10. Is there any other caliber that would shoot flat, wind resistant... up to 1000m?

Thanks for any information.

Dufus · April 8, 2020, 03:44 PM

None of them are wind resistant......but I went with the 308Win/7.62.

Lots of competitions have been won with a 308 Win.

Jim Watson · April 8, 2020, 08:32 PM

Having tried to make a .223 into a Long Range gun, I say to get one of the AR10 types in a recognized 6, 6.5, or 7mm.

TXAZ · April 8, 2020, 09:06 PM

6.5 Creedmoor is excellent at 1000 yards. But if you want the best, uou can get a .338 Lapua on an AR-10. Very flat shooting. Make sure you can afford to feed it though.
(An AR 50 is cheaper and more fun, but doesn't fit an AR-10 platform)

TRX · April 9, 2020, 10:34 PM

6.5mm is a sweet spot for sectional density. 6mm is technically not as good, but so much development has been done with the 6mms that in practice they do better at the range. Lots and lots of bullet development there...

There are lots of 6mm cartridges, but Mike Walker of Remington came up with the 6mm-.223 back in the 1960s and won benchrest competitions with it. It's now considered hopelessly obsolete by benchrest standards. The US Army evaluated the 6x45 a bit later and found it superior to the 5.56 in every way, but not enough to be worth dumping all their shiny-new 5.56s.

In the case of an AR, since it's basically just a necked-up .223, magazines and feeding aren't a problem. It's seriously old-school, but you can still find reamers and dies, or any decent barrelmaker should be able to handle it.

If you insist on "must be able to buy ammo at Wal-Mart", the 6.5 Grendel is a good choice.

April 8, 2020, 01:53 PM	#1
Ben64 Junior Member Join Date: April 8, 2020 Posts: 1	Long Range Caliber for AR Platform Hello All; I have been doing a lot of reading on the net about choosing the right caliber with a lot of contradictions and... I am more confused now. I am planning to build a long range precision AR rifle which will be solely used for targets and not hunting; I gave up hunting a long time ago. I would rather stay with the smaller frame AR15 but that is not a deal breaker. I know there are DPMS 308 Gen II which are smaller frame and POF Revolution AR10 which is the same size as AR15 (I don't like it since it is proprietary). lots of people are recommending 6.5 Creedmoor which fit AR10. Is there any other caliber that would shoot flat, wind resistant... up to 1000m? Thanks for any information.

April 8, 2020, 09:06 PM	#4
TXAZ Senior Member Join Date: September 5, 2010 Location: McMurdo Sound Texas Posts: 4,322	6.5 Creedmoor is excellent at 1000 yards. But if you want the best, uou can get a .338 Lapua on an AR-10. Very flat shooting. Make sure you can afford to feed it though. (An AR 50 is cheaper and more fun, but doesn't fit an AR-10 platform) __________________ Cave illos in guns et backhoes

April 9, 2020, 10:34 PM	#5
TRX Senior Member Join Date: September 24, 2008 Location: central Arkansas Posts: 400	6.5mm is a sweet spot for sectional density. 6mm is technically not as good, but so much development has been done with the 6mms that in practice they do better at the range. Lots and lots of bullet development there... There are lots of 6mm cartridges, but Mike Walker of Remington came up with the 6mm-.223 back in the 1960s and won benchrest competitions with it. It's now considered hopelessly obsolete by benchrest standards. The US Army evaluated the 6x45 a bit later and found it superior to the 5.56 in every way, but not enough to be worth dumping all their shiny-new 5.56s. In the case of an AR, since it's basically just a necked-up .223, magazines and feeding aren't a problem. It's seriously old-school, but you can still find reamers and dies, or any decent barrelmaker should be able to handle it. If you insist on "must be able to buy ammo at Wal-Mart", the 6.5 Grendel is a good choice. Last edited by TRX; April 9, 2020 at 10:40 PM.

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April 8, 2020, 03:44 PM	#2
Dufus Senior Member Join Date: December 10, 2014 Posts: 1,965	None of them are wind resistant......but I went with the 308Win/7.62. Lots of competitions have been won with a 308 Win.

April 8, 2020, 08:32 PM	#3
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,535	Having tried to make a .223 into a Long Range gun, I say to get one of the AR10 types in a recognized 6, 6.5, or 7mm.