Adjustable Gas Block with Picatinny Rail

[lee1000]

After hours and hours of searching I've been unable to find a steel adjustable gas block with a picatinny rail. Does anyone know of a company that makes them or knows of a company that's willing to modify a non adjustable gas block.

I did find this but there isn't a picture and I've never heard of the company. http://hahntactical.com/index.php?app=ecom&ns=catshow&ref=HT-2-Piece-Gas-Blocks&sid=669lrm9soolfpr046o0m7gvjl5r0yndm

I'm looking for an adjustable gas block because I'm a lefty and the rifle will be suppressed.

Here's my rifle configuration:
Colt Lightweight 6720
DD 14.5" barrel with carbine gas system, will pin flashhider.
Magpul SL handguard
Will be suppressed with a Sig 762SRD QD
I want to put a flip up front sight on the picatinny railed gas block. The gas block will be pinned or dimpled.
I want to mount the front sight to the gas block/barrel for durability purposes.

Gas Block Specs:
The gas block will ultimately be pinned or dimpled.
Steel or stainless steel
Must be rail height
Adjustable with detent locking screw. I've thought about taking the valve assembly out of an adjustable gas block and installing it in modified a non adjustable gas block.

Thanks in advance

[The Rat]

Why on earth would you want to rail mount anything to a gas block?

If you're going to the time and expense of switching out a gas block, you'd be much better off switching out the handguard at the same time to something longer and rolling with a regular low pro adjustable from SLR or the like. That way you can mount whatever you want to the handguard and not have to worry about direct heat from contact with the gas block.

[Clint]

Do you have a 6720 upper now?

Is the DD barrel being built into a second dedicated suppressed upper?

The pinned FSB that comes on the 6720 sounds like the best fit for your stated requirements.

A little more info would be helpful.




Here's my rifle configuration:
Colt Lightweight 6720
DD 14.5" barrel with carbine gas system, will pin flashhider.
Magpul SL handguard
Will be suppressed with a Sig 762SRD QD
I want to put a flip up front sight on the picatinny railed gas block. The gas block will be pinned or dimpled.
I want to mount the front sight to the gas block/barrel for durability purposes.

[lee1000]

Why on earth would you want to rail mount anything to a gas block?

If you're going to the time and expense of switching out a gas block, you'd be much better off switching out the handguard at the same time to something longer and rolling with a regular low pro adjustable from SLR or the like. That way you can mount whatever you want to the handguard and not have to worry about direct heat from contact with the gas block.

I figure it's more repeatable. If the sight is mounted on a handguard and the handguard is bump the front sight might be off. It's only aluminum. Just about every military rifle I can think of has the sight afixed to the barrel.

[lee1000]

Do you have a 6720 upper now?

Is the DD barrel being built into a second dedicated suppressed upper?

The pinned FSB that comes on the 6720 sounds like the best fit for your stated requirements.

A little more info would be helpful.

No, I'm modifying the Colt upper.

I just put a Aimpoint on it so I'm looking for flip up sights.

[lee1000]

Duplicate

[MegademiC]

No, I'm modifying the Colt upper.

I just put a Aimpoint on it so I'm looking for flip up sights.

Is there not enough material to create a shoulder?
If not, id leave it 16 at first and go from there.

That said, if you want robust irons, keep the fsb. A flip sight on a gas block is backwards.

[GH41]

If you must have a folding sight get one of these and either Clint's port kit or tube kit. Probably need to clearance the handguard to keep the sight off of it.
https://i.imgur.com/tVVdf9k.jpg

[lee1000]

If you must have a folding sight get one of these and either Clint's port kit or tube kit. Probably need to clearance the handguard to keep the sight off of it.
https://i.imgur.com/tVVdf9k.jpg

Clint who?


Thanks

[lee1000]

Is there not enough material to create a shoulder?
If not, id leave it 16 at first and go from there.

That said, if you want robust irons, keep the fsb. A flip sight on a gas block is backwards.

I'm replacing the barrel because of the lack of shoulder if I were to cut the barrel down to 14.5.

What do you mean by backwards? I'm open to suggestions

[Renegade04]

I'm replacing the barrel because of the lack of shoulder if I were to cut the barrel down to 14.5.

What do you mean by backwards? I'm open to suggestions

He probably means that you are creating a problem where there is no problem. A FSB is more robust than a flip-up sight on a railed gas block. As for the barrel, many have had barrel cut down, re-threaded, re-crowned, and new a FH attached. My advice, DO NOT modify the Colt upper. Leave it as is. Since you plan on running a suppressor, use a PRI Gasbuster charging handle. The thing is, you are trying to complicate the issue by changing things that should not be changed. Many carbines run with suppressors and without adjustable gas blocks run just fine.

[GH41]

Clint who?


Thanks

BRT is Clint.

[Rascally]

JP Enterprises used to make one, but it looks like it's been discontinued. Maybe you can find someplace that still has old stock? They still make an adjustable FSB, but it's clamp-on. Always out of stock with BCM, but Brownells has it. Other than that, the only adjustable railed gas block I can find is made by Double Star (??).

https://www.brownells.com/rifle-parts/gas-system-parts/gas-blocks/ar-15-m16-picatinny-rail-gas-block-prod29340.aspx

I have no idea of the quality of this. Of course if you go this route you'd then need to use a gas block height sight, such as one of these.

http://arpartsfinder.com/instock/index.cgi?type=sight&quant=25&s=gas+block&min=&max=&sortby=price-desc

Good luck.

[Defaultmp3]

I figure it's more repeatable. If the sight is mounted on a handguard and the handguard is bump the front sight might be off. It's only aluminum. Just about every military rifle I can think of has the sight afixed to the barrel.This is a non-issue if you get a halfway decent handguard that's not meant to be super lightweight. Many of the service rifles adopted in the last few years have a complete free float handguard with no sight attached to the barrel (New Zealand's LMT, France's HK416, USMC's M27, etc.).

[Iraqgunz]

Clamp on FSB blocks are garbage. If the upper doesn't work for your needs, sell it off and get the correct one before you butcher it.

[RobertTheTexan]

No, I'm modifying the Colt upper.

I just put a Aimpoint on it so I'm looking for flip up sights.

If your running a red dot, I would recommend a fixed sights. (But this is a long argument, but I still believe it’s a better set up) If you don’t want to want the FSP, remove it and use a lo-pro gas block and get a quality rail and mount a fixed front sight like a PRI, Daniel Defense, or Troy to your rail and stop worrying.

Your worry about your weapon losing zero because you whacked the rail against something is a little far fetched unless you are using a piece of crap rail and a piece of crap front sight and even the you’d probably have to whack it pretty hard. But no one here will recommend crap to you. So seek advice if you do not know what a good rail is.

How did you come up with that statement? Did you read it somewhere or just deduced that on your own?

I’ll ask if you are aware of just how many of us here and beyond used a fixed sights on the top picatinny rail? There are A LOT. In fact you will find members of M4C who took that exact configuration to Iraq and Afghanistan and killed bad guys, and brought those uppers home and still use them.

You may be rough on your firearms, but if there are 1,000’s of AR’s here and abroad with a rail mounted fixed front sights, I think it’s safe to say that is a good approach to take.

Me personally? I am not a fan of folding sights on RDS/HWS equipped rifles and if your main concern is the sight moving - well I’d bet you money I can get a folding sight attached to a rail section on a GB to move before you would throw a fixed sight on a rail or even more so an FSP out of zero/alignment.

I would suggest you are going down the wrong path with your idea and to be honest with you, I think your idea is not a good idea at all.

I am interested though in how you came to this conclusion about a a folding sight on a GB rail section.

You mentioned your rail is really thin aluminum. What rail do you currently own??

[Jammer Six]

If your running a red dot, I would recommend a fixed sights. (But this is a long argument, but I still believe it’s a better set up)

I'd like to read the argument. Is there a thread on it?

[lee1000]

If your running a red dot, I would recommend a fixed sights. (But this is a long argument, but I still believe it’s a better set up) If you don’t want to want the FSP, remove it and use a lo-pro gas block and get a quality rail and mount a fixed front sight like a PRI, Daniel Defense, or Troy to your rail and stop worrying.

Your worry about your weapon losing zero because you whacked the rail against something is a little far fetched unless you are using a piece of crap rail and a piece of crap front sight and even the you’d probably have to whack it pretty hard. But no one here will recommend crap to you. So seek advice if you do not know what a good rail is.

How did you come up with that statement? Did you read it somewhere or just deduced that on your own?

I’ll ask if you are aware of just how many of us here and beyond used a fixed sights on the top picatinny rail? There are A LOT. In fact you will find members of M4C who took that exact configuration to Iraq and Afghanistan and killed bad guys, and brought those uppers home and still use them.

You may be rough on your firearms, but if there are 1,000’s of AR’s here and abroad with a rail mounted fixed front sights, I think it’s safe to say that is a good approach to take.

Me personally? I am not a fan of folding sights on RDS/HWS equipped rifles and if your main concern is the sight moving - well I’d bet you money I can get a folding sight attached to a rail section on a GB to move before you would throw a fixed sight on a rail or even more so an FSP out of zero/alignment.

I would suggest you are going down the wrong path with your idea and to be honest with you, I think your idea is not a good idea at all.

I am interested though in how you came to this conclusion about a a folding sight on a GB rail section.

You mentioned your rail is really thin aluminum. What rail do you currently own??

I came up with it just by looking at it, the steel barrel is going to resist bending over an aluminum rail, I don't think that's even disputable. In addition to the 6720 I have a LWRC M6A2, just by comparing the two the barrel mounted sight looks more stout. Does it need to be that stout, maybe not.

I think you're right on using folding sights so I'm probably going to go with a JP A2 sight that's gas adjustable. It's steel and pinnable.

I did not mention that my rail was thin aluminum. It's actually a Magpul SL.

[RobertTheTexan]

I'd like to read the argument. Is there a thread on it?

There are definitely some threads that have this discussion. I’ll try to find it and post. It may not be titled as such, but I think the last one may be a thread HeruMew created on a build he did and that led into into discussion of fixed sights vs folding sights on a rifle equipped with a CQB optic. That’s the last thread I engaged my belief in and I’ll tell you from the comments, I think I was in the minority, with more guys wanting folding sights with their Aimpoints and EOTechs and MRO’s.

Because they don’t get in the way of looking through the optic.

Yeah. Not my thing, but to each their own. They make some good arguments, I just don’t agree with them. Lol

I’ll try to find some threads and shoot you an PM here on M4C. Don’t want to derail the OP’s thread.


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[MegademiC]

I prefer folding sights.
In reality, i havent seen a difference on a timer fixed vs folding.
I understand folding sights are less robust than a fixed fsb, but accept that as a compromise for a clear sight picture (for luxury).

Thats why taking a fixed fsb and replacing with a folder for robustness is backwards.

At the end of the day, if you die because your rail bent and threw off your poi so much you cant kill a threat... the gods were against you.

[lee1000]

Thats why taking a fixed fsb and replacing with a folder for robustness is backwards.

At the end of the day, if you die because your rail bent and threw off your poi so much you cant kill a threat... the gods were against you.

I was thinking the flip up sight might be somewhere in between. Less robust than a pinned A2 sight and more robust than rail mounted.


Haha, true

[Chris Bonesteel]

I came up with it just by looking at it, the steel barrel is going to resist bending over an aluminum rail, I don't think that's even disputable.

I find that very easy to dispute, typically handguards are over twice the outer diameter of the barrel, are much stiffer, and require far more force to bend, or even flex than the smaller diameter barrel. Material isnt everything, structural geometry plays a much larger role.

Handguards dont really bend, they can withstand quite a beating, and other than skewing them by actually denting one side in I dont think anyone will actually "bend" a free float handguard, it is most likely that they would crack first, which for all intents and purposes just isnt something to worry about happening.

Handguard attachments are a different story though,
Anything that doesnt affix the longitudinal positioning of the handguard, can have significant flex, and can be shifted under impact. Clamp style handguards only need to stretch a tiny bit around the circumference of the clamp (and only really at the front and rear of the barrel nut, at the centerline no stretch is required) for the rail to deflect significantly. If impacted they can also shift on the barrel nut and remain that way. If the handguard is fixed longitudinally(daniel defense, larue, almost noveske but the slots can cause shift) the handguard can not move separately from the barrel nut, and can only deflect as much as the rail actually flexes, which is extremely little, because in order to flex it must compress all the material on one side of the handguard, and stretch all the material on the other side(if unclear look up I beam strength for more detailed explanation).

Real world example, i have a bent 18" galil barrel, i can prop it on an angle and easily bend it with my foot like breaking a stick, i also have a 48" length of a handguard extrusion, despite the significant extra leverage that can be place on the 48" aluminum i still cant bend it.

Your assumption that steel is less bend prone than aluminum does not at all take into account geometry.