Barrel Profiles

[D.R.D.]

I'd read before somewhere on this forum of people advising against  'lightweight' profiles for a 308AR barrel.  Why is that?  Does it have to do with pressures?  Vibration of the barrel?  Something else?

 

Thanks

Edited June 25, 2014 by D.R.D.

[Robocop1051]

You never read that here... I would have blown a gasket if that were posted in this house.

[D.R.D.]

Ok,  So, lightweight 308AR barrels are good to go then?  

Like this one:

http://www.blackholeweaponry.com/catalog/product_info.php?cPath=48&products_id=211&osCsid=38881cc78b6b8648f370de928224b792

[Robocop1051]

That's not a lightweight barrel. That's just a standard barrel.

Fulton Armory sells a Criterion 16" ultralight barrel with a rifle length gas system. That is absolutely the lightest, NFA-legal, barrel you can get.... If you can find one.

[Robocop1051]

Lightweight barrels are absolutely a good way to go. I have a featherweight Rem 700 in .221 Fireball, that I'll put against any bull barrel for a single cold shot. Respect the barrel and understand the limitations of the cartidge, you'd be surprised how much you get out of very little.

If I didn't live in Kalifornistan, I doubt I'd own a barrel longer than 14" on any rifle.... I just don't see a need.

[D.R.D.]

If you are running a 308 and other 30mm calibers, is 14" really enough to reliably and accurately get you out to 1000m, especially in any wind? You'd have to be losing some considerable speed and lobbing it, no?

[Robocop1051]

Are you asking me to find the video of Travis Haley, shooting a suppressed subsonic 300Blk, out of a 9" barrel, using only a red dot, to hit his target at over 700 yards?

If you're just looking at accuracy, a 12.5" barrel will hit steel at 1,000 yards. Not saying the bullet would do much to a fleshy target at that distance... but it'll hit nonetheless.

Velocity helps against weather factors, but doesn't necessarily = accuracy.

[D.R.D.]

I've seen that video, and hear ya loud and clear.  Terminal ballistics are important to me at any distance.  So, I guess I'm constantly trying to figure out what's the minimum length barrel on a 308AR that will take me out to a grand, losing as little velocity and power as possible (with a decent 168 or 175 load).

[edgecrusher]

If that is ultimately what you are looking for, I would suggest 18". But with proper optics, bipod, most likely a PRS stock, you are looking at a rifle loaded out in the 13lb range. Perfect for setting up to shoot long distance.

[D.R.D.]

Cool.  Thanks.  That's what I was thinking.  Would you go mid, intermediate or rifle length gas in the 18" barrel?  And for this purpose do you think a heavier profile barrel would have much of an advantage on harmonics and accuracy at distance? 

[FaRKle!]

Cool.  Thanks.  That's what I was thinking.  Would you go mid, intermediate or rifle length gas in the 18" barrel?  And for this purpose do you think a heavier profile barrel would have much of an advantage on harmonics and accuracy at distance?

Rifle gas on everything 16" and longer.

A heavier (larger outer diameter) barrel will have more rigidity and thus less effects due to harmonics over a thinner barrel. Whether or not you're good enough to expose the difference remains to be seen (it likely won't be a huge amount).

Edited June 25, 2014 by FaRKle!

[edgecrusher]

Agreed ^^^^

I would try to get rifle, and I don't think the profile will affect it much (unless you are a professionally trained sniper you'll probably never even notice)

[D.R.D.]

I'll just have to go get me one of those mail-in professional sniper certifications then!   ;-)

 

Thanks guys.

[gnatshooter]

A heavier (larger outer diameter) barrel will have more rigidity and thus less effects due to harmonics over a thinner barrel.

 

For a good reference on barrel harmonics and tuning, I've found a good source to be:

http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm