HavasuMike Posted May 26, 2017 Report Share Posted May 26, 2017 I finished my first 308ar recently and I'm quite happy with it. It took my quite a while to build.since I'm a novice and had to do a lot of reading. It was a struggle but thanks to you guys and some other blogs, i got through it. Now I would like to build a 6.5 CM upper. What parts are different from the 308? What parts are the same? My 308 is a DPMS style and I am assuming that an upper will go right on the 308 lower. Quote Link to comment Share on other sites More sharing options...
EngrBob Posted May 26, 2017 Report Share Posted May 26, 2017 1 hour ago, HavasuMike said: I finished my first 308ar recently and I'm quite happy with it. It took my quite a while to build.since I'm a novice and had to do a lot of reading. It was a struggle but thanks to you guys and some other blogs, i got through it. Now I would like to build a 6.5 CM upper. What parts are different from the 308? What parts are the same? My 308 is a DPMS style and I am assuming that an upper will go right on the 308 lower. The barrel is different. Everything else is the same. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted May 26, 2017 Report Share Posted May 26, 2017 There are a few specific 6.5 muzzle devices, but they're all generally threaded 5/8x24, so you can still use a .308 size if you'd like. The 6.5 Creedmoor and the .308 are only about .001 off in measurements. The BCG's are interchangeable. This goes for .260 Remington too Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted May 26, 2017 Report Share Posted May 26, 2017 The folks over at Proof Research and JP seem to feel that it's best to use a "high pressure" bolt with the 6.5CM. Proof, has also come out with an extended length gas system barrel which included the gas tube to accommodate the pressures for the 6.5 Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted May 26, 2017 Report Share Posted May 26, 2017 (edited) This is my 6.5 upper plan. So far, I've got the receiver. 6.5 Creedmoor AR Upper SI-Defense Billet .308 Upper Receiver Falkor upper parts (port cover, spring, forward assist) Odin Works 15.5” M-Lok DPMS High (.210) Handguard 24” Proof Research Extended-Length 416 SS 4-groove .875 with gas tube Falkor High Pressure BCG Mega Arms Slide Lock Charging Handle PRI (.875) Adj. Lo-pro Gas Block Nathan Wright’s 3-port Beast Brake (.875) Edited May 26, 2017 by D.R.D. Quote Link to comment Share on other sites More sharing options...
HavasuMike Posted May 27, 2017 Author Report Share Posted May 27, 2017 Thanks for the info. It will be valuable. Are the magazines the same? Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted May 27, 2017 Report Share Posted May 27, 2017 Yes, As long as the OAL of the round fits and chambers, a 7.62 PMAG or the like will work for 6.5CM. Quote Link to comment Share on other sites More sharing options...
HotRod308 Posted May 27, 2017 Report Share Posted May 27, 2017 just removed a 6.5 CM barrel, 24 inches made by DPMS - 8.5 twist. Probably has some 2,000 -2500 rounds through it, 50$ and it's yours. If your interested in it. Quote Link to comment Share on other sites More sharing options...
HavasuMike Posted May 27, 2017 Author Report Share Posted May 27, 2017 Thanks for the offer, but not quite ready to get started yet. Is the 8.5 twist the most common twist rate? Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted May 28, 2017 Report Share Posted May 28, 2017 1:8 Quote Link to comment Share on other sites More sharing options...
HavasuMike Posted May 30, 2017 Author Report Share Posted May 30, 2017 Can you use the same buffer and spring? Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted May 31, 2017 Report Share Posted May 31, 2017 Yup. Just want to be sure you've got an adjustable gas block to tweak as needed. Quote Link to comment Share on other sites More sharing options...
Big Ironfoot Posted June 3, 2017 Report Share Posted June 3, 2017 I am also building a 6.5 upper, trying to choose a adjustable gas block now. I have the Ballistic Advantage 22" barrel. Need a .936 block. Any suggestions, as I have never used one before. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted June 3, 2017 Report Share Posted June 3, 2017 SLR, I have had good luck with them. http://slrrifleworks.com/index.php?route=product/category&path=57_103_168_105 Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted June 3, 2017 Report Share Posted June 3, 2017 I 2nd SLR, they are great gas blocks. Quote Link to comment Share on other sites More sharing options...
Big Ironfoot Posted June 19, 2017 Report Share Posted June 19, 2017 Well learned a lesson today. Don't assume anything when ordering parts in AR308 format. I purchased a DPMS a couple months ago, the rifle was purchased from a friend who had only had it a few months, and he purchased new. So I assumed it was a Gen 2. WRONG So the upper I bought won't fit. Big decision to make, send back and start over with finding Gen 1 upper in 6.5 or build a lower!!!! Ordered Aero Precision stripped lower to match my upper. Ordered A2 buffer tube, David Tubb buffer Spring, and buffer for rifle length gas system, Magpul PRS stock. Standard lower kit, and Magpul MOE grip. Should be here by the end of the week. Am so excited about this build. I just hope I get it right this time. Quote Link to comment Share on other sites More sharing options...
392heminut Posted June 20, 2017 Report Share Posted June 20, 2017 Keep everything and build more rifles! Quote Link to comment Share on other sites More sharing options...
Big Ironfoot Posted June 21, 2017 Report Share Posted June 21, 2017 Thanks to all, I have ordered the SENTRY 9 SET SCREW ADJUSTABLE GAS BLOCK. I am so anticipating the completion of this build Quote Link to comment Share on other sites More sharing options...
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