Doug H. Posted March 26, 2015 Share Posted March 26, 2015 I just ordered a 24" 6mm Creedmoor barrel for my JP LRP-07 from Rainier Arms. They are planning on getting a few made up from Shilen blanks to have ready for customers. My gun currently sports a .260 Rem barrel. Thought I'd try shooting super fast bullets out of my auto rifle and see how it fares up against the bolt guys. Should be interesting. Any body else have a 6mm CM in an AR-10 style gun? Doug Link to comment Share on other sites More sharing options...
ShooterSteve Posted March 27, 2015 Share Posted March 27, 2015 Keep us posted on how it goes. I have a big upper I want to rebuild. Link to comment Share on other sites More sharing options...
Graham Smith Posted March 27, 2015 Share Posted March 27, 2015 (edited) My main concern with the 6mm bullets is throat and barrel wear. I read that the 6mm Creedmoor is less prone to that than other 6mm calibers like the .243, but I'm not sure how much better better is - if you follow. It will be interesting to hear how you like this new barrel. Why the switch and why this particular caliber? Edited March 27, 2015 by Graham Smith Link to comment Share on other sites More sharing options...
Doug H. Posted March 27, 2015 Author Share Posted March 27, 2015 The .260 is nice but the 105 hybrid at 3000 will shoot way flatter and have less wind deflection. I shot sniper match a few weeks ago and 2 guys I was with were shooting 6mm SLRs and I was impressed. The 6mm CM has brass available from Hornady unlike the wildcats. Link to comment Share on other sites More sharing options...
dauntedfuture Posted March 27, 2015 Share Posted March 27, 2015 I will be interested to see what happens. Years ago when the AR-10 platform was new and guys were messing with non .308 in the rifles there were issues. I don't think that we had adjustable gas blocks and have learned a lot in the last 20 years or so. I should still think that you are not going to be able to run it as fast as a bolt gun. I would be looking for extractor marks on the brass as well as flattened primer pockets. Good luck and let us know what happens. I should think that there will not be an issue with feeding but who knows. Link to comment Share on other sites More sharing options...
Doug H. Posted March 27, 2015 Author Share Posted March 27, 2015 Bolt 6mms are running around 3150 with 105s, I hope to get close to 3000. Tuning should be interesting. Link to comment Share on other sites More sharing options...
R-Bros_JLR Posted March 27, 2015 Share Posted March 27, 2015 What are you running out of your 260 Doug? If you can get 140s anywhere close to 2800, it's a wash in windage against the 6mm. Link to comment Share on other sites More sharing options...
Doug H. Posted March 27, 2015 Author Share Posted March 27, 2015 (edited) I'm running 123 Lapuas at 2750 and showing slight cratering. Edited March 28, 2015 by Doug H. Link to comment Share on other sites More sharing options...
00MGN Posted March 28, 2015 Share Posted March 28, 2015 What powder are you using to cause cratering with 123 going that slow? Link to comment Share on other sites More sharing options...
Doug H. Posted March 28, 2015 Author Share Posted March 28, 2015 H4350, 43.3 gr. Link to comment Share on other sites More sharing options...
mic2377 Posted March 28, 2015 Share Posted March 28, 2015 That sounds pretty awesome, can't wait to hear the results. I had actually considered getting a barrel in 6 XC for my 308 AR, but elected to go with the 6.5 CM as it would also be used as a hunting rifle. I assume the reason you picked 6 Creedmoor vs the other 6 mm cartridges? (ie 243, 6 XC, etc.) was brass availability. Link to comment Share on other sites More sharing options...
DocMedic Posted April 9, 2015 Share Posted April 9, 2015 What are they charging for the ar-308 6mmCM barrel? Link to comment Share on other sites More sharing options...
Doug H. Posted April 10, 2015 Author Share Posted April 10, 2015 What are they charging for the ar-308 6mmCM barrel? I didn't ask but since I know those guys I'm sure it will be reasonable. I'll post the cost when it's delivered. I have powder, 4350 and 4831sc, 1700 Berger 105 Hybrid, primers, brass and a set of Whidden 6mm CM dies at the house, now I just need that barrel. Doug Link to comment Share on other sites More sharing options...
michael1778 Posted April 10, 2015 Share Posted April 10, 2015 What are they charging for the ar-308 6mmCM barrel? I didn't ask but since I know those guys I'm sure it will be reasonable. I'll post the cost when it's delivered. I have powder, 4350 and 4831sc, 1700 Berger 105 Hybrid, primers, brass and a set of Whidden 6mm CM dies at the house, now I just need that barrel. Doug Brother Doug, you are all set with that pile of reloading materials! I hope it's amazing for you. Link to comment Share on other sites More sharing options...
Stlhead Posted April 15, 2015 Share Posted April 15, 2015 Might as well have them spin you up a pair, they don't last long, and you will want a fresh one soon enough. Link to comment Share on other sites More sharing options...
fastarget Posted May 7, 2015 Share Posted May 7, 2015 should be getting close to 2K rounds with a quality barrel, and reasonable pressures. You will probably be adjusting the oal for wear around 6-800 rounds to keep the jump where you want it. My F class 26" is running 3143 with no signs of pressure, I have a PRS style 22" build that runs the same round at 3040 with no pressure signs, I have not shot that one as much since there are no prs matches around here at the moment.. Link to comment Share on other sites More sharing options...
Stlhead Posted May 30, 2015 Share Posted May 30, 2015 My experience with 6mm gas guns has them shooting barrels out much faster than the 2000 that you have gotten from your bolt gun barrels.in the 1200-1500 range. Link to comment Share on other sites More sharing options...
liber Posted May 30, 2015 Share Posted May 30, 2015 What are they charging for the ar-308 6mmCM barrel? I didn't ask but since I know those guys I'm sure it will be reasonable. I'll post the cost when it's delivered. I have powder, 4350 and 4831sc, 1700 Berger 105 Hybrid, primers, brass and a set of Whidden 6mm CM dies at the house, now I just need that barrel. Doug I'd be interested to know also, but must be bolt, barrel at minimum. Should be able to use the same mags. May need an adjustable gas block or special buffer as well. Seems an adjustable gas block would help tune it. Link to comment Share on other sites More sharing options...
liber Posted May 30, 2015 Share Posted May 30, 2015 Might use the 6.8 SPC bolt. They have one listed on the Ranier Arms site. Link to comment Share on other sites More sharing options...
Doug H. Posted May 31, 2015 Author Share Posted May 31, 2015 Barrels are only a few weeks out. Uses a regular AR-10 bolt. I'm getting jazzed to start working up a load! Doug Link to comment Share on other sites More sharing options...
liber Posted May 31, 2015 Share Posted May 31, 2015 Barrels are only a few weeks out. Uses a regular AR-10 bolt. I'm getting jazzed to start working up a load! That sounds cool, so it's only a barrel change? Must use the same mags also. Do you need a different buffer? Or just use an adjustable gas block? Link to comment Share on other sites More sharing options...
Doug H. Posted May 31, 2015 Author Share Posted May 31, 2015 Yup, just changing the barrel and I'm using the the same adjustable gas block that was on the gun. Doug Link to comment Share on other sites More sharing options...
liber Posted May 31, 2015 Share Posted May 31, 2015 (edited) Doug, I'll be watching this closely. I was reading that the head of the case was intentionally exactly the same as the 308 so that it could use existing actions. Anyway, I'm interested in this as I have a Rem 700 blank that I plan to mill and had been planning to make it 308, but since the bolt/action are exactly the same for the 6mm Creedmoor I'm interested in how your rifle works out. With the understanding that you're putting it on a semi-automatic action...maybe I'll just try a barrel on a LR-308 myself... What is the advantage over the 6.5mm Creedmore? (fps ?) Edited May 31, 2015 by liber Link to comment Share on other sites More sharing options...
Doug H. Posted May 31, 2015 Author Share Posted May 31, 2015 Speed, flatter trajectory with high BC bullets. I'm hoping to get close to 3000 FPS. My .260 Rem is running near 2750. Doug Link to comment Share on other sites More sharing options...
TXMXRACER Posted May 31, 2015 Share Posted May 31, 2015 Cool project. Interested to see how it runs. shane Link to comment Share on other sites More sharing options...
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