I purchased a URX II rifle length and I want to have it installed on a SR-15. Can this be done with no modification to the gas block on the SR-15? I understand the gas block on the SR-15 is a little further up than a standard mid-length gas system.
I believe the bottom corners of the gas block need contoured.
Ok, so it’s not the integrated front sight that interferes?
Right, I know of three or four guys here that have the rifle length URX II on their SR15’s, then a few more with the URX III.
What you’re thinking of is using the URX II with a mid length gas system, from what I understand. That’s when the front sight can interfere with the gas block.
You’re good to go.
Not to derail, but KAC modified the original URX II’s so they do work with a ‘regular’ midlength gas now. I run a rifle-length URX II on my BCM mid 14.5.
Thanks for the info, I wasn’t aware of that. Now that you mentioned it, maybe it was RustedAce that installed a URX II LW on a mid length…
My question is does it work with the sr-15 gas system, bc from what I know the sr-15 has a a slightly different mid-length gas system.
Yes it does. That’s what I meant in the first post…
Yes, we know.
jonconsig’s first answer was the right one- it’ll work fine, but you will need to shave the bottom corners of the gas block.
Pic from silencertalk:
Ok.
Thanks
Will switching the Kac gas block to a vltor low profile gas block work without having to shave the bottom?
maybe. the SR-15 uses a set screw gas block and most of these that I’ve seen need some shaving. I believe the YHM version does not. But, i’d be prepared to have to fit it.
ETA- if you switch to a pinned low pro block, that should fit fine, but the drilling and pinning will be more work than shaving the other set screw blocks.
Yes you can use the Vltor Lo-pro gas block on that. Here’s a picture of one that we did here.
Although I have said it before the CMMG Micro gas blocks work the best for fit under a URX system. And if you use rocksett when cranking things down that gas block ain’t going anywhere.
Hadn’t heard of the CMMG micro so went looking for it. Pretty cool, but $60?!
FWIW, perhaps not as low-profile as the CMMG, but having used Vltor and Larue in the past, I’m using the YHM-9383 exclusively now due to the $22 price tag. There are a lot of things I wouldn’t buy from YHM, but this is something I’m very happy with.
Yes, the YHM gas block is a great part from them, and priced very right compared to a lot of stuff out there.
So what do you recommend I do? Shaving the original KAC gas block or going with the VLTOR or CMMG gas blocks. This SR-15 will be used at an upcoming Magpul course I will be attending and I want this modification to be perfect. I’m concerned with the reliability of the weapon system being lost. Thanks for your help guys.
My immediate recommendation would be to not remove the current gas block. They are pressed on and deliver the best possible fit. If you do pull it off there is no guarantee that it will work on that gun again or as well. But there 's a catch 22 if you do decide to leave it on and merely swap the rails whomever loosens the current barrel nut on there and screws it up will essentially mean you will be taking your gas block off either way to replace it. My suggestion would be to send your upper to a dealer/gunsmith who both has the tools and skill to do a URX swap without taking the barrel nut off and make the modifications to the gas block. Simple right :rolleyes: I believe Wes at MSTN, the guys at Gun Gallery, Paul at BCM, or even Marvin Pitts would be more then capable of doing this sort of job for you with little trouble.