The obvious answer is to cut down a carbine barrel if doing an 11+/- inch sbr barrel. There is probably a simple answer, but could you take a rifle length barrel, and cut it just behind the gas port (at 12"), re drill the port, and end up with a much better profile and taper?
Thanks
You can cutb the barrel & redrill the gas port. As to whether you’ll end up with a better profile, that will depend on what you started with. Keep in mind that most AR barrels don’t taper past the chamber. The profiles usually run parallel forward of the chamber
I think your best bet would be to buy a barrel at the desired length. I don’t think it’s simple to install a gas block on a straight taper or non tapered barrel. I don’t even know how you would get one to fit depending on diameter.
You’d need one that’s a straight .750 or .625. A1 and A2 barrels typically have a long taper from .675 to .625 under the handguard, so that wouldn’t work without turning a seat.
This was the pic that got me thinking, but I get it now
http://www.rainierarms.com/rainier-arms-mountain-series-cold-hammer-forged-barrel-5-56mm-nato
Better profile? Dont know, thats dependent on several things.
But if youre moving gas blocks, always take careful measurement of the area where its going to be moved to, and leave some room for turning.
Often, the bore doesnt follow the od exactly through the center. If you cut the barrel midway, the bore may be a bit off center. If the od is already very close to size, there may not be enough material to center the muzzle of the bore again in the od. For a gas block, this only adds more work, as it has to be set up to the od, instead of simply installing a center in the bore. However, for muzzle attachments, especially if a suppressor is in the future for the barrel, this can be a big deal.
So, if the smallest gas block is .625", then you want the od of the barrel to be at least .675". Youre better off at .700". The closer to final size it is, the more centered the bore must be. You could clean it up at an od of .650", but it had better be close.
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If you have a lathe you can likely make it work, but you’d likely be better off just buying a pencil barrel if that’s what you want.
They said it tapers from .66 to .63
and nobody has even mentioned the crown.
gas port really needs to be in the groove of the rifling. What size gas port would you want with a barrel that length.
what gas tube length would you use
should be an interesting experiment
but I really think you would be much better off buying one the experts have already worked through these issues. they seem really cheap to me.
*I’m not set on it, but it was an idea I wondered about, and the discussion is interesting
Original question would be cutting off gas port and bulge and going down to 7" and doing a regular carbine gas setup. I’m already planning on cutting a barrel down and doing a custom port (paying an expert), when I looked at this rifle length barrel I thought maybe I could make a chf elw setup with my custom port.
The crown? I always crown a barrel i cut.
And not with some plunge cut tool, either, i physically cut the crown in the lathe.
I have a nice 11 degree custom made cutter though, if thats a preference. Its from some time back, i dont really use it anymore.
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