LET US DESIGN A 308 COMMANDO...OF SORTS

[M1A's r Best]

I'm supposing, if you buy a high quality barrel, the crown is part of the high quality cost/reputation for accuracy.

The comments about crown/barrel length and longer range accuracy reminded me that one of the best shooting AR15's I have has a barrel that came as a 20" barrel. I took it to a local guy that has a good reputation for tactical rifle work and had him cut the barrel to 18" so he put what he called a "match/target" crown on the barrel. The accuracy (group size/consistency even with 55 graim FMJ) surprised me when I got it back and finished the build.

Surprised me enough I wondered if I should take a couple more AR15's to him to have him remove the flash suppressors, do the same target/match crown job and reinstall the flash suppressors to see if it improved the groups on those rifles. Then I did my usual and forgot about it as I moved on to other projects.

Has anyone here explored different angles, steps, etc. when recrowning AR10 barrels to see if accuracy can be improved?

[LawDog]

Has anyone here explored different angles, steps, etc. when recrowning AR10 barrels to see if accuracy can be improved?

I've only looked at the crown to ensure that it isn't damaged. I like a recessed crown generally, but also figured it was somewhat irrelevant with a rifle that was going to have a muzzle device attached. I've never before heard about crown angle having a significant effect upon accuracy. It would be interesting to see someone conduct a truly scientific study of this variable--take one quality barrel and slowly increase the crown angle, testing the gun between steps. Basically the same thing as Ballistics-by-the-Inch, but focused on crown angle rather than barrel length.

[mrstang01]

I'm in too, as I have a lower put aside for a .308 build before the recent craziness, and it wasn't high enough up the priority list at the time to get a matching upper. I was planning on 18" barrel, but I'd have no issues with a 16 for my AOP. I've just heard several folks (not necessarily on this list, but qualified shooters), who indicated that down around 16 and shorter, you were really giving up the .308 and may as well have a .300 BO or 7.62AK.

[chad newton]

I'm in too, as I have a lower put aside for a .308 build before the recent craziness, and it wasn't high enough up the priority list at the time to get a matching upper. I was planning on 18" barrel, but I'd have no issues with a 16 for my AOP. I've just heard several folks (not necessarily on this list, but qualified shooters), who indicated that down around 16 and shorter, you were really giving up the .308 and may as well have a .300 BO or 7.62AK.

Not true, you only loosing about 150fps going from 20”-16”.... I will look stuff up so you can see it...

[LawDog]

I'm in too, as I have a lower put aside for a .308 build before the recent craziness,

The next time around, half of us need to stockpile uppers.

[mrstang01]

Yep, seems like I should have planned this better.

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[chad newton]

I started another on barrel length to not derail your thread bro.... Plus I know you don’t want to turn this system into a sniper thread...

[ronlassit]

I already have one of those rifles, a CMMG mk3 CBR. 16" 1-10 barrel, Geissle trigger, Magpul ACS stock, grip and AFG, MI muzzle brake that works very well and it weighs in at 9.5 lbs with the gen 2 PST 1-6 and Warne mount. Shoots around 1" if I feed it the loads it likes. Digests all ammo fed it without complaining. Now the pistol with a rds instead of a heavy optic, with an adjustable gas block sounds very interesting. I would suggest the POF dictator 9 position block and 3.5 lb trigger. With a little tweaking I bet you could easily get it under 7 lbs. and it could probably push 150 gr bullets around a little north of 2000 fps. Shiney, let's be bad guys.

[Knowledge]

I already have one of those rifles, a CMMG mk3 CBR. 16" 1-10 barrel, Geissle trigger, Magpul ACS stock, grip and AFG, MI muzzle brake that works very well and it weighs in at 9.5 lbs with the gen 2 PST 1-6 and Warne mount. Shoots around 1" if I feed it the loads it likes. Digests all ammo fed it without complaining. Now the pistol with a rds instead of a heavy optic, with an adjustable gas block sounds very interesting. I would suggest the POF dictator 9 position block and 3.5 lb trigger. With a little tweaking I bet you could easily get it under 7 lbs. and it could probably push 150 gr bullets around a little north of 2000 fps. Shiney, let's be bad guys.

What grain bullet shoots the best in your bbl?

[Redneck Zen]

I've only looked at the crown to ensure that it isn't damaged. I like a recessed crown generally, but also figured it was somewhat irrelevant with a rifle that was going to have a muzzle device attached. I've never before heard about crown angle having a significant effect upon accuracy. It would be interesting to see someone conduct a truly scientific study of this variable--take one quality barrel and slowly increase the crown angle, testing the gun between steps. Basically the same thing as Ballistics-by-the-Inch, but focused on crown angle rather than barrel length.

Captain Obvious here. I've always preferred shorter barrels more for aesthetics and handling than anything logical. To that end, I've read several articles in the old gun magazines over the years regarding barrel length and accuracy. The rule is length increases velocity (positive influence) and barrel harmonics (negative). A few articles compared identical guns with contrasting barrel lengths (and in a couple of cases cutting and re-crowning the barrel on the same rifle); the result was shorter guns were more accurate due to decreased barrel vibration. Longer barrels benefit from being thicker (bull barrels) which cuts down on vibration.

Don't know nuthin' 'bout which crown angle is best except that many barrel makers like 11 degrees.

I finally saw the light regarding the importance of crowning a couple of decades ago. I have a vintage High Standard Sport King with a spare gun show purchased bull barrel I had threaded for my old Form 1 suppressor. I was vexed because it wasn't very accurate, which I laid blame on the can. Gave it to a gunsmith to mount a picatinny rail, he crowned the barrel for me and accuracy went from "meh" to amazing. From a rest I can hit stationary clay pigeons at 100 yards with just a red dot. The pistol is kinda heavy, as is the can (a converted C-cell Maglite), but it's handier and as useful as a rimfire rifle.