12.5 " barrel

[cjgemm]

will a midlegnth gas system work with a 12. 5 inch barrel? I have a 18 I was thinking of cutting down.

[txgunner00]

It should if you get the gas port size correct. You probably will need a larger port to compensate for decreased dwell time. Reliability may suffer as a result though.

[LRRPF52]

I would prefer a CLGS for a 12.5" gun, not MLGS. Leave the 18" or sell it to get the 12.5" if you want it that bad. An 18" barrel will sell like crack right now, but I wouldn't let it go personally. I've been wanting an 18" for a long time, but settled for a 16" years ago.

[txgunner00]

I agree. You might trade it for a 16" if you don't want the 18". That way your out of pocket is the same to cut it to the length you want and reliability will be better.

[cjgemm]

I hear what your saying. I have another 18 in the works from Templar. I picked this barrel up cheap on ARFCOM. looked around and even finding a 16" barrel with a carbine gas system is hard. Every thing is midlength. Its an idea though. Ill post a trade and see what happens.

[LRRPF52]

If I were you, I would look around for a burnt .264" bore pipe from one of the competitive shooters that runs 6.5x284, .260 Rem, or something like that. I bet if you PM'd stokesrj, he could point you in the right direction.

Take that barrel, have it cut and re-profiled to your liking, threaded for a quality AR15 barrel extension, and drive on from there. It will be a shooter if it was on a match gun, and a competent smith turns it true on the spin axis of the lathe, without inducing heat stress.

Another option would to be just getting a barrel blank from Brownell's and starting from scratch. Cutting a 16" CLGS would be the cheapest route, other than getting a new 12.5" pipe.

[Brag]

The 6.8 and Grendel are different beasts, but they are quasi similar

I have a 12.5 inch 6.8 with Mid gas, it function perfect, but it does look weird with the gas block 1 inch away from the muzzle device.

In my 12.5 inch 6.8, factory SSA 85TSX shoots 2900 fps, same ammo in a 16 inch 6.8 is 3000. I suspect the #s will be close between a 16 inch Grendel and a 12.5 Grendel. Anyone have a link to 12.5 Grendel ballistics(I've seen an AA pdf before, I'll search for that) I have an 18 inch 264, next one I'm going longer.

Cool project, short barrels are very handy.

[cjgemm]

Well I did it, chrono'd at 2275fps with factory Hornady 123 Amaxs.

[LRRPF52]

What gas port diameter did you go with, and is it running reliably? That is a MLGS, correct?

[cjgemm]

Not, sure if ADCO modified the GP or not, only ran 10 rounds total (5 Wolf MPT & 5 Hornady 123 AMAXs). put all spent brass @2:30 about 3ft away. 34 deg and windy. Correct MLGS.