DPMS barrel / LAR8 upper...

[Caliper]

New member here, I've read some older threads on the forum where forum members have found that DPMS barrels will fit a RRA upper:

Reading both threads, folks are reporting that the headspace is on the tight side using this combination (RRA bolt, DPMS barrel) has anyone compared the RRA to the DPMS bolt? I'm wondering if the DPMS bolt face is a hair deeper than RRA, or the locking lugs are a bit shorter or something. Is it possible that the DPMS bolt could fit in the RRA BCG?

I'd help with measurements, but my LAR8 is still on order from Dec '12... Just looking ahead and know that I want to switch calibers but RRA has stopped selling anything but a .308 barrel (very distressing).

Edited March 8, 2014 by Caliper

[EasyEJL]

I believe its probably equivalent to the "using an AR10 barrel in a LR308", to where you need to match the barrel with the bolt. so for a RRA barrel, use an RRA bolt. The carrier should be the same on any of them. in the end if you are going to switch calibers if you get a custom / semi custom barrel made you can send in your bolt and they'll headspace to match.

[600hpSBC]

Greetings all from Northern Illinois. I have been following this forum for a while and have been frustrated too with the lack of caliber options on the Rock River platform. I'm a retired Marine, hotrodder, shooter and wanting to help supplement my "budget" and was wondering:

Would anyone pay $1000.00 for a full float tube equipped Rock River LAR 8 compatible upper with a 20" light contour 338 Federal barrel or a heavy contour 260 Remington? This would be complete with no bolt or charging handle. (Use your bolt, carrier and charging handle). Just wondering if there is a market after I get done testing. Lead times would apply of course due to the industrial base demand right now. Thanks for the time annd space! Y‘all be safe, Semper Fi!

KBob

[unforgiven]

Welcome from Indiana brother Bob and THANK YOU for you'r service.That is a interesting option,I am a RRA fan.So the same LAR-8 BCG would work with these 2 calibers???

[600hpSBC]

Thanks for all the support man. Anyhoo, thats the plan sir, to not have to buy a new bcg. Testing will have to bare this out, but my goal is 260, 308 and 338 with same bolt:-) Thus far, tolerance stack is agreeable, so going to test more and hope for the best!

[unforgiven]

Good luck brother,keep us informed. <thumbsup>

[98Z5V]

I believe its probably equivalent to the "using an AR10 barrel in a LR308", to where you need to match the barrel with the bolt. so for a RRA barrel, use an RRA bolt. The carrier should be the same on any of them. in the end if you are going to switch calibers if you get a custom / semi custom barrel made you can send in your bolt and they'll headspace to match.

Rock River 308 bolt carriers are longer than DPMS/SR-25 bolt carriers / Armalite AR-10 carriers. 

 

That's one of the bigger differences in the 3 major patterns we deal with.

[planeflyer21]

True…the carrier is almost an inch longer.

 

As are the charging handles.

 

And why you need the 1" stock extension with the MagPul PRS.

[EasyEJL]

crazy rock river arms bastards. I've never looked at one close as I didn't see the point :)

Is the bolt still the same even if the carrier is bigger?

[Tripledeuce]

    Yes, the bolt is the same, just the carrier is different.

     Respectfully

     Terry

[600hpSBC]

Update: For my three uppers (260, 308 and 338 Fed), I am using the same BCG. Anyone want one?:-) kineticpandm.com/products. Check it out:-)