.750" Gun Block Installation Trouble

[freedom-lover]

The OD of the barrel is exactly 0.750", but the YHM gun block ID is 0.746".
Any ideas? I thought the gun block would simply slide on and then one could dimple the barrel for the set screws. But, it appears that there is a 0.004" interference fit.

[supertrooper]

its gas block not gun block. it should be a snug fit so gas doesnt leak when firing. get a brass punch and tap it on.

[Rusty Scabbard]

barrel in freezer, gas block heated to 300 F may help. Get it all set up to align and press into place quickly.

[freedom-lover]

its gas block not gun block. it should be a snug fit so gas doesnt leak when firing. get a brass punch and tap it on.

Ooops, I typed too fast, meant to say gas block. Thanks for the idea.

[kendog4570]

The OD of the barrel is exactly 0.750", but the YHM gun block ID is 0.746".
Any ideas? I thought the gun block would simply slide on and then one could dimple the barrel for the set screws. But, it appears that there is a 0.004" interference fit.

Which gas block? Pinch type? If it is, spread it slightly with a small wooden wedge. If it is conventional type, send it back.

[freedom-lover]

Which gas block? Pinch type? If it is, spread it slightly with a small wooden wedge. If it is conventional type, send it back.

Conventional type

[kendog4570]

Conventional type

If it is truly .746, return it. It should be a light friction fit, not a .004" press fit.

[Seesm]

That's pretty tight... You should NOT have to hammer it on with that much interference. But having said that I have a hone I can open it up to whatever call out you want... .750 is really right where you want to be.

[donmopar]

I would say that it is better to tight even if it needs to be heated up to put on. When you shoot it will heat up and loosen up naturally.

[ar15barrels]

The OD of the barrel is exactly 0.750", but the YHM gun block ID is 0.746"

What are you using to measure?

[CRTguns]

its gas block not gun block. it should be a snug fit so gas doesnt leak when firing. get a brass punch and tap it on.

You'll never "tap" a .004 press without damaging the gb.

[ar15barrels]

You'll never "tap" a .004 press without damaging the gb.

I want him to try so we can see the pictures of the mayhem later.
I have never seen a gas block actually measure under 0.750"
I bet he measured with calipers...

[jfifer]

Calipers wont be as accurate. Maybe an ID micrometer or telescoping gauges for an indirect reading followed by a 1" mic.

[paratroop]

I just installed a rather tight gas block. I hit the inside with some 1000 grit paper, to smooth it out and clean some gunk off. After that, went on nice and easy.