How hard is it to replace the gas block on an AR?

tapeman1 · Jul 2, 2015

I want to replace the old school, tall post style block on a Colt 6721 with a low profile block. Is this something I should have a gunsmith do? Does it require specialized tools?

mopar92 · Jul 2, 2015

Two pins use a punch and a BIG hammer to whack em out. Tap the gas tube roll pin out and replace gas tube on low profile block.
Thats the hard way.
Easy way is whack the two taper pins out and cut down the bayonet lug and FSP. Remove handguard and barrel nut and replace with free float handguard of your choice.

F-Stop · Jul 2, 2015

Are you wanting it lower for aesthetics or for it not to be in the way of a new handguard, sight? I would have it cut and retain the nice fit of the original. Just me though.

Sometimes they can be tough to convince off. You will need to remove the muzzle device also if present.

TWS@Tannermans · Jul 2, 2015

If you do decide to remove the A2 sight the pins are directional need to be removed from left to right and installed right to left pertaining to the 6721

outrider58 · Jul 2, 2015

Just be sure of which side of the taper pins you use your punch on. The answer is: The side of the sight that has the narrower pin ends is the side you apply the punch.

NateIU10 · Jul 2, 2015

Cut it and use the original, IMO.

tapeman1 · Jul 2, 2015

F-Stop said:
Are you wanting it lower for aesthetics or for it not to be in the way of a new handguard, sight? I would have it cut and retain the nice fit of the original. Just me though.

Sometimes they can be tough to convince off. You will need to remove the muzzle device also if present.

New hand guard.

SO you guys think cutting the existing A2 block is the way to go? I doubt I'll ever decide I want one in the future.

BradMacc82 · Jul 2, 2015

tapeman1 said:
New hand guard.

SO you guys think cutting the existing A2 block is the way to go? I doubt I'll ever decide I want one in the future.

Chopping the FSB is relatively easy. The hard part is driving out the taper pins.

The barrel and FSB are drilled/reamed to mate up already, so it makes perfect sense to re-use it when possible.

And if you're willing to spend some time smoothing out your work on the FSB, it can look pretty good too, if you don't hide it under the new handguard/rail system.

tapeman1 · Jul 2, 2015

Alright...IT'S DREMEL TIME!!!

Thanks for the advice, fellas.

BradMacc82 · Jul 2, 2015

Reinforced cut-off wheels are your friend.

BigT5g · Jul 2, 2015

I have used both methods, and for a handguard that will cover the block, cutting it is the way to go!

tapeman1 · Jul 2, 2015

BradMacc82 said:
Reinforced cut-off wheels are your friend.

My wife loooooves the sound of that thing.

She'll be so happy.

clandestine · Jul 2, 2015

You are going with the most secure method. Good decision!

If your not removing the FSB, taper the hell out of the barrel in case you slip with the cutoff wheels.

As Outrider said, LOOK at the taper pins, they don't always come out the same way depending on who drilled the taper pins, and some AR'S use straight pins and not taper pins.

tapeman1 · Jul 2, 2015

clandestine said:
You are going with the most secure method. Good decision!

If your not removing the FSB, taper the hell out of the barrel in case you slip with the cutoff wheels.

As Outrider said, LOOK at the taper pins, they don't always come out the same way depending on who drilled the taper pins, and some AR'S use straight pins and not taper pins.

I'm assuming you meant tape and not taper?

Thanks for the advice. I'll wrap it up good. :thumbsup:

clandestine · Jul 2, 2015

tapeman1 said:
I'm assuming you meant tape and not taper?

Thanks for the advice. I'll wrap it up good.

Lol, yup.

tapeman1 · Jul 2, 2015

clandestine said:
Lol, yup.

I like to think I'm pretty good with a Dremel, but tapering a barrel with one sounds like a recipe for disaster.

Sticky · Jul 2, 2015

clandestine said:
You are going with the most secure method. Good decision!

If your not removing the FSB, taper the hell out of the barrel in case you slip with the cutoff wheels.

As Outrider said, LOOK at the taper pins, they don't always come out the same way depending on who drilled the taper pins, and some AR'S use straight pins and not taper pins.

True, I have one that still sports the orginal A2 front sight, but employs a quad rail. Decided that the original sight was about as tough as it could be and kept it to add a fixed rear. Worked out well.

tapeman1 · Jul 2, 2015

Sticky said:
True, I have one that still sports the orginal A2 front sight, but employs a quad rail. Decided that the original sight was about as tough as it could be and kept it to add a fixed rear. Worked out well.

Do you use an optic?

Sticky · Jul 2, 2015

A red dot sight that cowitnesses in the lower 1/3. Works out pretty well.

tapeman1 · Jul 2, 2015

Sticky said:
A red dot sight that cowitnesses in the lower 1/3. Works out pretty well.

That's what I'm "worried" about. I've never used co-witness before. I feel like the picture would be too crowded for me.

I don't want to buy a riser for the optic and magnifier I'm getting just to decide I don't like it.

How hard is it to replace the gas block on an AR?

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