AR gas block sizes?

[Pharr Shot]

The different sizes I guess of AR gas blocks, would that be like the width of the hole that the barrel goes into or what?
I've been trying to figure it out now for a while and couldn't come to a conclusion.
Hopefully y'all know more than me on this.
Hopefully y'all understand the question I'm asking.


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[BeRotten]

The different sizes of gas block are in relation to the diameter of the barrel where the gas block mounts...mostly. The common sizes are .625 for a light weight barrel, .750 for a heavier barrel, .936 for a heavy barrel. The barrel manufacturer should provide this information. The distance form the stop for the gas block and the gas port is pretty much standard. There are different heights of gas blocks too. Low profile for mounting under a free float or higher for mounting sights on. And the standard A2 style that acts as a front sight and gas block. Hope this helps.

 

[ASP785]

Gas block size corresponds with the diameter of the at the gas port.

 

[Pharr Shot]

The different sizes of gas block are in relation to the diameter of the barrel where the gas block mounts...mostly. The common sizes are .625 for a light weight barrel, .750 for a heavier barrel, .936 for a heavy barrel. The barrel manufacturer should provide this information. The distance form the stop for the gas block and the gas port is pretty much standard. There are different heights of gas blocks too. Low profile for mounting under a free float or higher for mounting sights on. And the standard A2 style that acts as a front sight and gas block. Hope this helps.

That's what I was thinking but wasn't quite sure myself.
As far as I know this helps me out a lot!
Now I just gotta' figure out what size GB I need and learn how to take off and put one on.
But that's what YouTube is for.
From what it seems mine might be a .750, it's just the standard barrel that comes on the DPMS Oracle. It's a bit different from a plane jane standard/military style barrel.


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[gfercaks33]

You going to a low profile? It should have a set screw underneath you loosen up to separate from the barrel, to get the gas tube out its just a roll pill.

 

[Super Dave]

Your barrel will be one of the three sizes in the gas block area. Measure it. Order accordingly. I'd bet you are right about it being .750".

As for port size, the barrel has the correct port size, not the gas block. Don't worry about that.

Did I read it right that you have a DPMS Oracle? What's wrong with the gas block that you have? Getting a fancy floating rail thingy?

 

[Pharr Shot]

Your barrel will be one of the three sizes in the gas block area. Measure it. Order accordingly. I'd bet you are right about it being .750".

As for port size, the barrel has the correct port size, not the gas block. Don't worry about that.

Did I read it right that you have a DPMS Oracle? What's wrong with the gas block that you have? Getting a fancy floating rail thingy?

Yes, I have the DPMS Oracle.
Yes, I'm gonna' get the Samson 12.5" key hole mid rail for it.
The gas block I have (which IMHO is stupid and doesn't make any sence) is the low profile but with the rail on top.
So instead if me using the Magpul front flip-up (which I bought before the Brownells &#128542 I hadda' get a Brownells flip-up front so it would line up with the Magpul MBUS that I have on it since the rail on top of the receiver and the gas block rail don't line up evenly.
So I kinda wasted around $60 just because the rails ain't lined up, thank you to whoever made the LP gas block w/ a rail on top *sarcasm* 😑.
All in all though, I'll have my perfect rifle here soon.


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[Pharr Shot]

You going to a low profile? It should have a set screw underneath you loosen up to separate from the barrel, to get the gas tube out its just a roll pill.

Mine looks like it has two set screws but that shouldn't be a big problem.


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[Super Dave]

Yes, I have the DPMS Oracle.
Yes, I'm gonna' get the Samson 12.5" key hole mid rail for it.
The gas block I have (which IMHO is stupid and doesn't make any sence) is the low profile but with the rail on top.
So instead if me using the Magpul front flip-up (which I bought before the Brownells �&#56862 I hadda' get a Brownells flip-up front so it would line up with the Magpul MBUS that I have on it since the rail on top of the receiver and the gas block rail don't line up evenly.
So I kinda wasted around $60 just because the rails ain't lined up, thank you to whoever made the LP gas block w/ a rail on top *sarcasm* ��.
All in all though, I'll have my perfect rifle here soon.


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What about chopping off the top of the gas block that you already have? I chopped of a front sight base (also is the gas block) to go under a lightweight YHM floater on an AR that I used to own. Got any friends with metal cutting means? It is certainly an option..... Probably.

Take pictures of whatever you end up doing, and post them. We likes the pictures around here. Pictures good. Ugh.

And for what it's worth, you can almost always sell your old parts, so you didn't waste your money. Sell 'em!

 

[Pharr Shot]

What about chopping off the top of the gas block that you already have? I chopped of a front sight base (also is the gas block) to go under a lightweight YHM floater on an AR that I used to own. Got any friends with metal cutting means? It is certainly an option..... Probably.

Take pictures of whatever you end up doing, and post them. We likes the pictures around here. Pictures good. Ugh.

And for what it's worth, you can almost always sell your old parts, so you didn't waste your money. Sell 'em!

I wish I knew someone with the tools or else I would cuz it would save me a couple bucks.
I'm more than likely gonna' sell my old parts for when I swap them out.


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