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werra
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« on: February 03, 2010, 14:21:09 » |
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To those of you in the know, do you think it would be reasonably possible to flute or turn down the XCR's 16" 6.8 barrels to a smaller dia? Has this been done before? I really want to reduce some barrel weight!
Also, anyone here have a 1:11 twist, 16", 6.8 barrel? What do you think of it? What did it cost you??
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crenca
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« Reply #1 on: February 03, 2010, 15:47:27 » |
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I heard some of the guys have sent their heavy XCR barrels to Addax Tactical to for fluting. I am curious as to how many ounces it really reduces. However, I would think it reduces them in the right place - up front where the XCR is already heavy. Hopefully a user that has done this will post a comment.
As far as 1:11 twist, it would be an improvement. However, the more I read about it seems the chamber spec and number of grooves are more of a factor in pressure and the ability to load rounds hot. Since the XCR is good in these areas (SPECII chamber and 4 grooves) the 1:11 twist probably would not be noticeable/significant (as far as pressure). Still, it might improve the ballistics of the very light 85/90 grain bullets by reducing spin and thus yaw induced drag IF this is a problem (have not read anything either way)...
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"Of all tyrannies a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience..." C. S. Lewis
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werra
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« Reply #2 on: February 03, 2010, 16:39:52 » |
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Thanks for the reply crenca! I have heard of the .223/5.56 barrels being fluted, but am trying to find out if it can be done on the 6.8 barrels specifically. There is probably less room to work with due to the larger 6.8 bore. Perhaps reducing the outer diameter a little is possible? I have heard of some AR 6.8 barrels being turned down to .600 dia. Can it be done on the XCR 6.8 barrel?? Not sure what the current XCR outer dia. is for comparison.
Does Robarms even make 1:11 twist, 16" XCR barrel? I hope so!!!
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Gibal
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« Reply #3 on: February 03, 2010, 21:12:21 » |
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Mine is stamped 1/11.
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werra
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« Reply #4 on: February 03, 2010, 21:20:56 » |
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Mine is stamped 1/11.
Gibal, is it a 16" barrel? How's it shoot? |
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Gibal
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« Reply #5 on: February 03, 2010, 21:50:03 » |
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Good, I haven't ran anything too hot through it yet. It's a replacement barrel... I had some bad luck with my gun until I talked to Terra and she sorted things out. I put some SSA combat loads through it and and moderate pressure reloads (27gr. reloader 10x, 115gr fmj) that did fine in the original but showed some signs of under pressure... could just be from the gun re-breaking in (or my imagination). I just got it back so I'm only at 450 rounds on the new upper.
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crenca
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« Reply #6 on: February 04, 2010, 02:10:07 » |
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Mine is stamped 1/11.
Are you in Canada? IIRC, the only 1/11 6.8 barrels Robinson had were all going to Canada and were not available here in USA... |
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"Of all tyrannies a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience..." C. S. Lewis
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aziator
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« Reply #7 on: February 04, 2010, 09:59:02 » |
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I will have to look at mine and see what they are
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"Play to win, or don't bother. Check friendship at the door. A "friendly game' is a contradiction of terms. When looking for entertainment, there is the theater. When camaraderie is your need, there is the bar."
-Doc Holiday
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Gibal
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« Reply #8 on: February 04, 2010, 10:00:02 » |
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Terra
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« Reply #9 on: February 04, 2010, 10:55:32 » |
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we have never done it here. There is significantly more pressure in the barrel before the gas block.
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God, grant me the serenity
to accept the things I cannot change;
the courage to change the things I can;
and the wisdom to know the difference.
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werra
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« Reply #10 on: February 04, 2010, 11:46:25 » |
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we have never done it here. There is significantly more pressure in the barrel before the gas block.
Terra, Sorry, I'm not sure I follow. Are you saying that Robarms does not carry 1:11 twist 6.8 barrels or that ya'll don't offer a light 6.8 barrel? The 1:11 twist should be lower pressure. I'm confused  I really, really want a new 1:11 barrel! Help meeee!!!!  |
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DSM
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« Reply #11 on: February 04, 2010, 12:45:45 » |
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I believe she's referring to a light 6.8 barrel.
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I know not what tomorrow brings, I know only what I bring to tomorrow.
2B1-ASK1
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crenca
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« Reply #12 on: February 04, 2010, 20:42:58 » |
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Terra, just to be clear you are NOT recommending fluting of our 6.8 barrels correct?
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"Of all tyrannies a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience..." C. S. Lewis
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bolster
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« Reply #13 on: February 07, 2010, 17:20:49 » |
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Terra, just to be clear you are NOT recommending fluting of our 6.8 barrels correct?
If you did flute it, you would want to make the flutes shallower than those on a 5.56 due to the larger bore diameter. |
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crenca
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« Reply #14 on: February 09, 2010, 14:28:24 » |
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Terra, just to be clear you are NOT recommending fluting of our 6.8 barrels correct?
If you did flute it, you would want to make the flutes shallower than those on a 5.56 due to the larger bore diameter. That makes sense. I was just wondering if RA fealt like the barrel should not be fluted at all. I think I had read about someone here fluting their 7.62x39 which I think (alot of "thinking" in know  ) is made from the same blanks... |
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"Of all tyrannies a tyranny exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience..." C. S. Lewis
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Gibal
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« Reply #15 on: February 09, 2010, 16:21:05 » |
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The reloading books I have put 5.56 52k and 6.8 at 55k psi (it may be c.u.p.) they're pretty close.
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bolster
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« Reply #16 on: February 09, 2010, 21:22:52 » |
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I'm happy with the 6.8 barrel's weight as it is. I can feel a difference between it and the 5.56 HBAR I've got.
There are, and have been, light 6.8 barrels on the market for AR's, so I don't see why the XCR can't run one. They would just need to adjust the lathe for it.
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Terra
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« Reply #17 on: February 09, 2010, 21:32:05 » |
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we are no longer making the 1/10s. All 6.8s shipping now are 1/11.
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God, grant me the serenity
to accept the things I cannot change;
the courage to change the things I can;
and the wisdom to know the difference.
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bolster
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« Reply #18 on: February 10, 2010, 00:29:03 » |
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we are no longer making the 1/10s. All 6.8s shipping now are 1/11.
Good news. Any thinner profiles in the works? |
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nomspc
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« Reply #19 on: February 18, 2010, 06:59:48 » |
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I've used Steve at ADCO firearms to both flute and recontour XCR heavy barrels in 5.56, 6.8 and 7.62X39. Good work, reasonable price, quick service.
-Steve
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