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01-09-2015, 06:05 AM
(This post was last modified: 01-09-2015, 06:12 AM by Thevic.)
Hi guys thanks for having me on the forum! Forgive me if this topic has been gone over too many times...
For about a year I've been sitting on a Grendel build I have planned and I am finally finding time to port and chamber the barrel...I am using a Bartlein 5R 1/7.75 blank that is profiled for a rifle length gas. Using a Grendel reamer with the same neck as a .264lbc... My plan was to finish it at 20" with an adjustable gas block and I was wondering what gas port size I should use at 20".
I will also be shooting suppressed most of the time so I was starting to hope I can go go down to 18", but can I get reliable function out of a rifle length that short? Someone was telling me to use .102 gas port, but that seems pretty large.
-Vic
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I think I remember LRRPF52 saying that a rifle length system is designed to function with .094 inch gas port. I measured mine and it is dead nutz .094 with my 20 inch barrel that PF machined for me. Hope this helps but I am sure others with many times more experience than me will have more extensive info as to barrel length and such.
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Thanks guys.
Victor M.
Spartan Precision Rifles
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Especially if you are going to suppress it, there is no reason to open up a RLGS port beyond .094" for a 20". For an 18"/RLGS, Hank Rearden got reliable function with .094".
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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My 18 bbl the gas port is .100. I had to try different gas blocks, buffer weights, bolt carriers. I finally got it to cycle.
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usmc1371 Wrote:My 18 bbl the gas port is .100. I had to try different gas blocks, buffer weights, bolt carriers. I finally got it to cycle.
What combo worked for you? Include the load, factory or hand loads as well.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
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I used a low pro gas block. Ar15 bcg. And a h3 buffer. The only ammo I'm using is factory hornady sst. It took awhile for me to get it to work. I ended up putting the gas block right against shoulder. That was the only way I could get enough restriction. An adjustable gas block didn't help much. It just made my hand guard hard to put on. I did notice that my buffer spring was long by about .75. The coils were were fewer and farther apart.
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I think I'll just play it safe with a .094 at 20". I'll be shooting mostly long range anyways so I might as well keep the extra 2"
Victor M.
Spartan Precision Rifles
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01-11-2015, 03:11 PM
(This post was last modified: 01-12-2015, 05:07 PM by LRRPF52.)
My long range stick the gas port is .09. It is also a 24" bbl. My 18" was built for CQB and shorter ranges.
