View Full Version : Low Profile Gas Blocks
Why is it that I see a lot of the low pro gas blocks exposed from the free floating rails?
I would think that they would like to tuck it under the hand guard.
Or that it can't fit under some certain rails?
If its adjustable, is it easier to access the adjustment screw when it's sticking out like that?
My first thought when I see a low pro gas block that is not under the rail is that whoever built that gun didnt know what the hell they were doing(including the big manufacturers). I personally see no reason to use a low pro gas block unless you need to to tuck under a rail.
bullittmcqueen
02-24-13, 09:41
My first thought when I see a low pro gas block that is not under the rail is that whoever built that gun didnt know what the hell they were doing(including the big manufacturers). I personally see no reason to use a low pro gas block unless you need to to tuck under a rail.
Agreed. The whole purpose of it being"low profile" is to fit underneath a tube or rail. If someone has a lo-pro GB sitting on their barrel outside of a rail, why not just use the standard A2? SMH.
Perhaps they are caught up in the newest coolest tactical ok thing to do.
Unless the "who ever built the gun " knows that most folks rip off the handguard and install a rail. Added benefit
Why is it that I see a lot of the low pro gas blocks exposed from the free floating rails?
I would think that they would like to tuck it under the hand guard.
Or that it can't fit under some certain rails?
If its adjustable, is it easier to access the adjustment screw when it's sticking out like that?
Some people prefer a shorter rail and don't care it the gas block sticks out. I'm not one of those people. I like the lo-pro, but its got to be covered by the rail on my uppers. This means at least a 9" rail for carbine length or 10" for a middy.
I have both fixed front sight uppers and lo-pro uppers. Both work, but I prefer the more un-obstructed view from the lo-pro. I use Aimpoints, and while I am completely capable of ignoring the big thing sticking up right in the middle of my view, I prefer to shoot without it.
Unless the "who ever built the gun " knows that most folks rip off the handguard and install a rail. Added benefit
Not entirely accurate, if I understand you correctly... it's not a very practical solution to address a customer demand. While yes, it does eliminate the need for the replacement or shaving down of the FSB, it's still not exactly a drop in job. Having a stock config sans the FSB would still require the removal of the handguard cap and the delta ring + spring. That, plus the fact that a good number of FF rails have proprietary bbl nuts so you may or may not have to take it apart to accommodate that as well.
Why is it that I see a lot of the low pro gas blocks exposed from the free floating rails?
I would think that they would like to tuck it under the hand guard.
Or that it can't fit under some certain rails?
If its adjustable, is it easier to access the adjustment screw when it's sticking out like that?
Good question. I personally don't care for the appearance of such guns nor, the railed type gas blocks either for that matter. I much prefer a clean FF rail from front to back covering the GB and providing all the real estate needs for attachments.
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Not entirely accurate, if I understand you correctly... it's not a very practical solution to address a customer demand. While yes, it does eliminate the need for the replacement or shaving down of the FSB, it's still not exactly a drop in job. Having a stock config sans the FSB would still require the removal of the handguard cap and the delta ring + spring. That, plus the fact that a good number of FF rails have proprietary bbl nuts so you may or may not have to take it apart to accommodate that as well.
Right. No big deal and nothing but the rail to buy (if you have a wrench). Pop the pins, slide off the gas block, off with the nut and delta ring. Install nut, gas block, rail ....45 mins and your done. No clamp on blocks, no set screws. No grinding and cutting.
I just built a SPR-ish upper that has an exposed low profile gas block. I used a Larue 12.0. I would have preferred the 13.2 model, but this was what I could get. I expect that I will upgrade to the 13.2 in the future and use the 12.0 on a midlength carbine, but in the meanwhile I'll just have to live with it.
I dont think it matters much on SPRs since you have enough rail estate as is with a 12". It's an issue with carbines wherein you barely have enough rail as it is and yet some insist on doing so to get the look of an exposed gasblock similar to that of i guess the SR and some LMT offerings. Classic case of form over function... Even on a middy, thats functionally pushing it and i have a partially exposed gasblock on mine with my mk18 rail. It works just right for me and keeps things consistent between it and my sbr but if i ever did, somehow, discover another, better config (for me, anyway), i'd probably have to scrap. There's no slack beyond it's current config for me.
watertower
02-25-13, 07:51
I just built a SPR-ish upper that has an exposed low profile gas block. I used a Larue 12.0. I would have preferred the 13.2 model, but this was what I could get. I expect that I will upgrade to the 13.2 in the future and use the 12.0 on a midlength carbine, but in the meanwhile I'll just have to live with it.
I did the same thing a couple years ago with a 20" barrel while building a SAM-R type upper. I bought a stripped barrel and wasn't going to drill it to pin a front sight tower, nor did I want to spend the money for a PRI flip up front sight, so I used a low pro gas block in front of a Larue 12" rail.
As mentioned, I really don't think it's a big deal with a rifle gas system, there's plenty of rail.
My 18" 6.8 hog rifle has a low-profile gas block in front of a 9" Clark CF tube.
I went that route because the Clark is an epoxy job and putting the hand guard over the gas block would've meant I could never remove it or the barrel without destroying the tube. It's not a defensive weapon so going with a standard FSB wasn't necessary.
My last build has the lo pro sticking out about 1/4". I don't know what I'm doing! :lol:
91advrunner
02-25-13, 12:33
If you're going I build a gun without knowing exactly what your plans are a low pro is a good solution... If it ends up showing who cares.
My last build has the lo pro sticking out about 1/4". I don't know what I'm doing! :lol:
I wouldnt say 1/4" is "not knowing what you are doing". Exposing the whole gas block with part of the gas tube showing as well is "doing it wrong". Or using a clamp on low pro gas block to hold the front of a set of non free float hand guards.
yeah apparently BCM doesnt know what they are doing either then :jester:
Gun Runner
02-27-13, 20:49
yeah apparently BCM doesnt know what they are doing either then :jester:
And whoever came up with the Mk 12 (http://en.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle)
And whoever came up with the Mk 12 (http://en.wikipedia.org/wiki/Mk_12_Special_Purpose_Rifle)
That gas block in no way could be tucked under a rail and wasnt designed to be. I believe the OP is talking about(and what I know I have seen) are low pro gas blocks that have no flip up sight or rail on them because they were designed to go under a rail.
Now, im sure when that gun came out if they had wanted a longer rail somebody could have made one, but when the SPR's were released I dont believe there were really any 15" rail systems in existence. I mean today there arent a ton of 15" rail systems in existence.
Gun Runner
02-27-13, 21:12
That gas block in no way could be tucked under a rail and wasnt designed to be. I believe the OP is talking about(and what I know I have seen) are low pro gas blocks that have no flip up sight or rail on them because they were designed to go under a rail.
Now, im sure when that gun came out if they had wanted a longer rail somebody could have made one, but when the SPR's were released I dont believe there were really any 15" rail systems in existence. I mean today there arent a ton of 15" rail systems in existence.
The Mk 12 Mod 1 has a low-profile KAC or DD or Badger gas block (depending on the source of info, they're all about the same).
http://www.mk12.net/MOD_1/MOD_1.html
When I built my 20" rifle length gas system upper there were no, or not many hand guards that would cover the gas bock. Hence, I have a clamp-on lo-pro gas block outside the very end of the rifle length ff tube.
Counter-point: I don't understand the use of set-screws on gas blocks when its so inferior to clamp-on, or taper pinning. At the time of my build I couldn't find a single lo-pro gas block designed for taper pins without the set screws. Maybe I'm just missing some critical element of the design.
My last build has the lo pro sticking out about 1/4". I don't know what I'm doing! :lol:
The horror! Cover your gas blocks, its for the children!
Some people modify a rifle/carbine based on need/budget or an eye towards future upgrades. Not everybody builds a rifle to enter internet picture thread beauty contests.
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Counter-point: I don't understand the use of set-screws on gas blocks when its so inferior to clamp-on, or taper pinning.
I'd never us a clamp on. If the set screw backed out for some reason.. the inner diameter of a real gas block isn't going to change... and it likely wouldn't move.
If a clampy's screws back out, the gas pressure will open the inner diameter up I bet...
Why's everyone worried about other peoples gasblocks? To each their own. As long as its pinned it'll work.
As long as its pinned it'll work.
What if it's not pinned?
It'll still work. Just feel more secure with it pinned. Pardon the omission.
It'll still work. Just feel more secure with it pinned. Pardon the omission.
I agree. I mean... I'm running a few unpinned... but if it were my primary gun... I'd get it pinned for sure.
I assembled my first clamp on recently and got all concerned with how l'll be checking for looseness after I covered it up with my tube.
Sometimes we worry about the wrong things. All I know is that it's working. I'll worry about it when it doesn't.
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I assembled my first clamp on recently and got all concerned with how l'll be checking for looseness after I covered it up with my tube.
Sometimes we worry about the wrong things. All I know is that it's working. I'll worry about it when it doesn't.
can you see the fasteners? I use paint pen to make witness marks when I can see fasteners that I'm concerned about.
I'd never us a clamp on. If the set screw backed out for some reason.. the inner diameter of a real gas block isn't going to change... and it likely wouldn't move.
If a clampy's screws back out, the gas pressure will open the inner diameter up I bet...
I'm just the oposite. I've never seen a set-screw or pinned gas block that had a proper interference fit to a barrel. They've all been at least a few thousandths loose. This means even when pinned the fit isn't perfect. A clamp-on fits perfect every time even if the barrel diameter is a little off. The screws can be staked, loctited, and then the block can be redundantly pinned just for good measure.
I'd still like to see a lo-pro pin-only gas block, especially one that actually needed to be heated to be installed.
I'm going to do a MK18 upper in the future, and will be using a MK12 gas block like they use on these type of weapons.
As far as I know, the military doesn't use pinning of the gas block. Has anyone heard of any problems with the gas block giving problems or would a person need it pinned to be on the safe side?
Just curios, and who would you recommend to pin the block?
Thanks
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