Gents and gals....I have a nice Daniel Defense bbl inbound,should be landing here soon...looking at a bit of a conundrum...I have a complete A2 sight assy,and I also have a railed alloy gas block on the way,..this is a 16" 1/7 carbine bbl...What is the best option for this bbl. and why?
What's the scoop on AR gas blocks?
- Thread starter SA85M1
- Start date
First of all the barrel OD must match the ID of the gas block. If you're going to use an optic & don't mind the iron sights co-witnessing with it the A2 sight will be OK. If BUIS co-witnessing with the optic bother you then you'll want to go with the railed gas block and mount a folding BUIS on it. Remember also that front BUIS come in two heights, one for same plane mounting and one for gas blocks that sit lower than the railed forend. You probably have the latter but you would want to check before buying a front BUIS.
mildcustom2
CGN Ultra frequent flyer
- Location
- Surrey, B.C.
All depends on wether your going to use a free float setup or 2 piece non free float and if you want that post sight sticking up. A railed gas block may not work and have clearance issues if your free float rail or fee float hand guard goes over top of the gas block.
Cutting the standard A2 sight down is a possibility if you need it to work on a free float assembly but one thing to remember is the backing plate that sandwiches in between the A2 gas block/sight for the 2 piece hand guards will need to be removed, moving the cut down gas block back and can partially cover the gas port as a result depending on the size of the hole in the gas block.
Some barrel manufactures actually take this into consideration like Kreiger with there DCM profile barrels. However it can have the opposite effect and create an issue for guys wanting to use a low profile gas block and cover the gas port hole if the hole in the gas block isn't big enough. The standard distance for the gas port is .298" from the machine edge if I remember correctly.
So there's lot to think about here before just jumping into things and cutting or buying stuff. Best to get your parts, measure, test fit and make sure it works the first time so you don't waste your money.
Cutting the standard A2 sight down is a possibility if you need it to work on a free float assembly but one thing to remember is the backing plate that sandwiches in between the A2 gas block/sight for the 2 piece hand guards will need to be removed, moving the cut down gas block back and can partially cover the gas port as a result depending on the size of the hole in the gas block.
Some barrel manufactures actually take this into consideration like Kreiger with there DCM profile barrels. However it can have the opposite effect and create an issue for guys wanting to use a low profile gas block and cover the gas port hole if the hole in the gas block isn't big enough. The standard distance for the gas port is .298" from the machine edge if I remember correctly.
So there's lot to think about here before just jumping into things and cutting or buying stuff. Best to get your parts, measure, test fit and make sure it works the first time so you don't waste your money.
I have a railed handguard that will accomodate either front sight...One question I have is definetly reliability,..and another would be accuracy...I can understand why the A2 would be stronger,...though would the railed gas block be better accuracy wise?...A bit more work to install the A2,but that is not a concern..
mildcustom2
CGN Ultra frequent flyer
- Location
- Surrey, B.C.
Well Armalite uses a railed gas block instead of the standard A2 setup on its AR10 target rifles, DPMS uses a similar gas block on its Bull Barrel target AR15's and Rock River Arms uses a railed gas block on its Varmint series target AR15's so I really don't see the issue. Why would so many manufactures prefer this setup on a precision AR if it affected accuracy or reliability.
I honestly don't understand where the reliability issue would come from if you buy good quality products that are made for your application.
I think there is a relibality issue with the attachment points of a railed/or other screw set gas blocks,compared to the standard pinned A2 assembly....Likely it will not matter to me as I do not plan on crawling through the mud much...The A2 will require some fitting and drilling....the other block,...not so much...hmmmmm..six of one, half dozen of the other perhaps?
mildcustom2
CGN Ultra frequent flyer
- Location
- Surrey, B.C.
I suppose that could happen but you can get gas blocks that clamp on instead of using set set screws which may help. I'm installing a low profile gas block on my precision AR build right now and I figure as long as I tighten the screws pretty good and use a bit of blue loctite I shouldn't really have a big issue down the road.
It is a bit of a pain in the @ss picking, for me I had no choice and needed a low profile gas block to fit under my free float quad rail. I guess another deciding factor will be if your barrel has the slots in it for the pins on an A2 gas block and sight. No pin slots on my Kreiger barrel so again I have no choice.
Yeah,..the 7" handguard I'm using will allow either gas block to be used....she will lilely be used for 3 gun at some point in the future....don't think she has the slots for an A2 set up...will have to align the sight tower and set up the drill press....not a big deal..just a bit more work..The several builds done here have been inclusively A2,....not much use of other set ups...
mildcustom2
CGN Ultra frequent flyer
- Location
- Surrey, B.C.
I think the slots are a taper fit correct me if I'm wrong? I would be concerned about heat when drilling or reaming if you did it yourself. Also the steel or stainless used in barrels is probably pretty tuff stuff so they don't prematurely wear out, requiring special bits to drill it or if tapered a special taper reamer.
mildcustom2
CGN Ultra frequent flyer
- Location
- Surrey, B.C.
I may get flamed for saying it but I absolutely hate the A2 gas block/sight. Just looks like a big triangular turd hanging off the end on the barrel. I prefer a cleaner look.
So I guess I'm kinda bias.
So I guess I'm kinda bias.
Unless you are a pretty skilled machinist if your new barrel doesn't have the cross pin slots already cut it's a job you might want to leave to a good gunsmith. If improperly cut you'll end up with a canted front sight and aside from welding up the slots & recutting them (and welding and barrels seldom go well together) I don't know that you could fix it.
I used an a2 on my build because I liked the look. cut the bayonet lug and drilled and tapped holes in the bottom and used set screws. that was a couple thousand rounds ago and its holding up best kind. Personal preference I guess. This was oneway around drilling for taper pins.
Bolivar
CGN Ultra frequent flyer
That sounds interesting. Any chance you can post a picture or two of that setup?
