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3/14/2014 5:27:54 AM EDT
I'm planning a rifle build and want something larger than a 223/5.56 to fit in an AR15 platform.  I found a great article here on the 6mmAR based on the 6.5 Grendle case but that build had a few cost and compatibility issues.  Since I don't need the last shred of velocity from this target/dog gun I was thinking about just using the 6mmBR as is.  As long as the OAL stays within the required magazine length I would think the added neck length would be an advantage in a semi-auto gun.  Am I ignoring any problems this idea may incur?  Any suggestions on someone to build an upper?

Thanks
Robin
3/14/2014 5:31:52 PM EDT
[#1]
I would go 6.8 SPC as it seems to be the most prevalent mid-size cartridge and would make a Sweet A2 build  
3/14/2014 7:24:04 PM EDT
[#2]
Welcome. Your question will be appropriate in this section of the forum:

Variants
3/14/2014 7:37:16 PM EDT
[#3]
Topic Moved
3/15/2014 2:18:50 PM EDT
[#4]
Quoted:
I'm planning a rifle build and want something larger than a 223/5.56 to fit in an AR15 platform.  I found a great article here on the 6mmAR based on the 6.5 Grendle case but that build had a few cost and compatibility issues.  Since I don't need the last shred of velocity from this target/dog gun I was thinking about just using the 6mmBR as is.  As long as the OAL stays within the required magazine length I would think the added neck length would be an advantage in a semi-auto gun.  Am I ignoring any problems this idea may incur?  Any suggestions on someone to build an upper?

Thanks
Robin
View Quote


Too much work for little gain. The Grendel made into a 243 LBC (virtual twin to the 6mmAR)  will handle anything you want with big bullets and in the field you will not see any difference. Not many AR 15 6 BR barrels out there. In the 243 LBC there are a few. I see Les Baer got out of the game. Black Hole is making good ones and Whitley is a good source too. Also 6.5 brass is much easier to find than 6 BR stuff.

Greg
3/15/2014 2:42:16 PM EDT
[#5]
Take a look at the 6 WOA/6mmSPC, or the 6mmDTI.  These are based on the SPC case and are a very easy conversion.  Plus, brass is readily available and cheaper than grendel/lbc brass.
3/15/2014 3:55:22 PM EDT
[#6]
Quote History
Quoted:
Take a look at the 6 WOA/6mmSPC, or the 6mmDTI.  These are based on the SPC case and are a very easy conversion.  Plus, brass is readily available and cheaper than grendel/lbc brass.
View Quote


Or order the 6X6.8 from Black Hole and have it on your upper in 8 weeks. Load it with a Redding bushing die and a Hornady seater and you will be good to go. No need for fire forming and you have more capacity than the WOA.

Greg
4/1/2014 7:57:08 AM EDT
[#7]
The Hagar is another good choice if using varmint bullets or loading long single shot. Creedmoor Sports has dies and brass.
There are a few companies selling the 6mmAR/243LBC. Great Lapua brass can be used.
BRAT Rifleworks was making 6mmBR uppers.
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