Gas Tube from AR Sight Tower

[biglucky]

I am having a problem that I hope someone here can help with.

I am working on installing a 9" free float RIS on my 10" AR15 SBR. This of course means I have to remove the front sight tower and install a low profile gas block. I have got everything taken apart, but am having a hard time getting the sight tower to "let go of" the gas tube.

Does anyone have a recommendation on how to get the gas tube out of the sight tower.

 

[40Arpent]

I don't mean to insult your intelligence, but you did remove the retaining roll pin, right? If so, try soaking overnight with penetrating oil.

 

[biglucky]

Yes I removed the roll pin. I have tried break free, but I guess I went a little short of "soaking it". Thanks.

 

[biglucky]

Any particular oil you would recommend? Just a bunch of break free?

 

[40Arpent]

When I say "penetrating oil" I am referring to products like Kroil, PB Blaster, Liquid Wrench, etc., that are designed to loosen stuck/rusted fasteners. I listed them in order of effectiveness, but Kroil is typically only available online or through industrial suppliers. You should be able to find PB Blaster at your local hardware or auto parts store. Spray liberally and let it "soak" for a few hours.

Another suggestion would be to let the sight/tube sleep overnight in the freezer. Different degrees of contraction between the two metals can cause them to break free of one another. This can also be achieved by alternating between hot and cold, e.g., moving parts from boiling water to ice water.

 

[jdh]

Leave the tube in and shave the sight risers from the gas block, then reuse the original (now low profile) gas block?

 

[MadMo44Mag]

When I say "penetrating oil" I am referring to products like Kroil, PB Blaster, Liquid Wrench, etc., that are designed to loosen stuck/rusted fasteners. I listed them in order of effectiveness, but Kroil is typically only available online or through industrial suppliers. You should be able to find PB Blaster at your local hardware or auto parts store. Spray liberally and let it "soak" for a few hours.

Another suggestion would be to let the sight/tube sleep overnight in the freezer. Different degrees of contraction between the two metals can cause them to break free of one another. This can also be achieved by alternating between hot and cold, e.g., moving parts from boiling water to ice water.

++1
In the machine shop I have had to do this many times with very good results. It works especially well on dissimilar metals. Steel on aluminum ect..

 

[GI-John]

I got a flask size can of kroil at "collectors firearms"

 

[TSU45]

Leave the tube in and shave the sight risers from the gas block, then reuse the original (now low profile) gas block?

And the gas block would still be pinned on instead of clamped/tensioned.

 

[jdh]

And the gas block would still be pinned on instead of clamped/tensioned.

It would be the gas block that was fit to that barrel at the factory and does not need to be clamped or tensioned to make it work/fit right. Put it back on, put the taper pins in and it is lined up with the gas port in the barrel and ready to go shoot.

 

[TSU45]

It would be the gas block that was fit to that barrel at the factory and does not need to be clamped or tensioned to make it work/fit right. Put it back on, put the taper pins in and it is lined up with the gas port in the barrel and ready to go shoot.

Correct. I was agreeing and stating an additional benefit in my first post.

 

[biglucky]

Leave the tube in and shave the sight risers from the gas block, then reuse the original (now low profile) gas block?

That is a great idea, however I don't think I have the tools to do that.

 

[jdh]

Hack saw and a Dremil tool will get it done.

 

[ebk06]

Heres a link to help you out with making your own low profile gas block. Theres also a how to on removing the sight if you are having trouble. Assemble your own LOWER, UPPER, FREE FLOAT, TRIGGER, GAS BLOCK - Step by step instructions! - AR15.COM

 

[biglucky]

Heres a link to help you out with making your own low profile gas block. Theres also a how to on removing the sight if you are having trouble. Assemble your own LOWER, UPPER, FREE FLOAT, TRIGGER, GAS BLOCK - Step by step instructions! - AR15.COM

Thanks man that is a great link. I didn't think a dremel cutting wheel would cut through that sight tower.