AR 15 and 6mm calibers

H

hiwayman

New member
I would like to build an AR 15 in a 6mm caliber for long range varmint hunting. mostly shooting 100gr. and down to 70 gr. lead.
I see many different discussions on this and am undecided which caliber to choose.
Any suggestions? Ease of acquiring brass and forming are considerations. I don't have saw's, or annealers and only a forster manual trimmer.
Thanks in advance.
 
Probably a 9 twist 6x6.8 or 6 dti. However there is a point where the grendel case might be better when you get to a longer bullets. I'd say it depends what you call long range too. I think out to 350 or 400 the 70 grain pills are hard to beat. Beyond that 243 is the sensible thing to do imo. Hence why I just ordered my second bear creek arsenal 243 ambidextrous charging upper. For 300 bucks its a no brainer.
 
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AR10 6mm Creedmoor would be my pick.

Except for the little Grendel size case, I think most .243/6mm's are going to be on the bigger AR10 platform, not the AR15.
 
243 lbc or 6x6.8, are both easy peasy. I was originally in the lbc camp and it's a good one, but have a 6x6.8 now. Same capacity and speeds more or less, and a 22" barrel in either will get you within 125-150 fps of a 20" 243. 6x6.8 is good up to 87 vmax easy, the lbc is probably a better choice above that. The 6dti is an improved 6x6.8 so also a great choice. For colony varmints or coyote these are great choices.
 
My AR15 6x6.8 will push the Sierra 85 Gamekings
2751 FPS out of a 16 inch Suppressed BHW
Barrel , with steady 1/2 inch groups at 100 yds.
 
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Originally Posted By: varminter .223Probably a 9 twist 6x6.8 or 6 dti. However there is a point where the grendel case might be better when you get to a longer bullets. I'd say it depends what you call long range too. I think out to 350 or 400 the 70 grain pills are hard to beat. Beyond that 243 is the sensible thing to do imo. Hence why I just ordered my second bear creek arsenal 243 ambidextrous charging upper. For 300 bucks its a no brainer.

My second bear creek 243 upper should be here in a few days. Before bear creek started making these it would had been $1500 on up if you wanted a 243 AR/LR 10.
 
Coyotes and prairie dogs out to 500. My old eyes don't work much past that. 20 or 24" varmint weight. I have a walk around rifle already.
The 6x6.8 sounds interesting. brass is easy to find.

 
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That's a great choice IMO. I love the 243, and have one in a DPMS g2, and also have a 243 Wssm ar, and both are AWESOME, but for pdogs they burn too much powder, too much barrel heat, too short barrel life. Great for anchoring coyotes though.
 
The 6x6.8 and 6DTI are essentially identical cartridges and they shoot identical loads. I've owned them both.

The major difference between them is the quality of barrel. The Shilen 6DTI barrel is clearly superior.
36709748680_3350478afb_c.jpg
 
I have an AR10 in 6mm Creedmoor that I'm really happy with. There is quality Lapua brass that is readily available and it isn't hard to find Hornady or other less expensive brass.

A 243 win or 243 WSSM would also be great options for AR10's that are 6mm.

A 22 Nosler would be a top pick for me if I wanted to stay with the smaller frame AR15 for longer range shooting.
 
Originally Posted By: steve garrettI say forget about the heavy bullets. in that case I would want a 6mm hagar. if doing it again that is what I would go with.

What would you expect velocities to be with anywhere from 55gr to 70gr bullets on the 6mm Hagar and 20-22" bbl? Thanks
 
+1. This year with my 6 DTI, I used 58gr vmax running 3530 out of a 20", last year I ran 75 gr vmax @ 3200 (suppressed). Both work great on coyotes, with minimal fur damage.
 
Hagar will hold about 1.5 grain more powder than the 6x6.8.
I was in contact with woa about building one but I never got a return phone call. Then the bca ambedextrios 243s came on scene.
 
Here’s my 1/9 twist 22” stoner upper. It was $449 when I bought it last year. It’s a re branded and inflated priced Bear Creek Arsenal upper. They don’t offer the stainless 1/9 twist anymore but offer the same platform with a blued barrel in a 1/8 twist for $390.00. I bought an complete Areo M5 lower minus the buttstock. They’re $249.00 right now but sold out yesterday. Bought mine on Black Friday for $213.00

BCA has the complete rifle in stock right now for $606.00

I added a 2.5 CMC single stage trigger that brakes at 2.2 pounds, a new grip, a Remington buttstock, and removed the bird cage and replaced it with a $10 fluted thread protector I found on amazon. She’s a heavy tac driver. I have two different 55 grain NBT loads that shoot .3”, 100 yard groups. One is a hair under 4K and the other is loaded a little hot and pushing 4100 FPS. A lot tighter grouping than I expected for the money I paid for it. I had 6 different loads I tested the same day that all shot SUB MOA.

XIlfRFM.jpg
 
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Originally Posted By: DiRTY DOG
The major difference between them is the quality of barrel. The Shilen 6DTI barrel is clearly superior.
36709748680_3350478afb_c.jpg


I believe Shilen barrels are good stuff, so I can't say that you're wrong on the superiority of the barrel. However, I would like to know your reasoning.
 
my experience is a 20" 6mm dti, I only shoot 55's @3525, I would expect maybe an extra 40FPS with the longer hagar case and I would expect 50-100 fps faster with the 22" barrel, so I would shoot for 3600 fps and probably call it a day.

I might just get a 22 nosler instead though, more bullets to shoot in the ligher ranges, what would be an interesting setup though is a 20 nosler.
 
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