Moly Grease Under Gas Block/FSB

[dp0350]

I generally just apply moly grease to the barrel and receiver extension threads during builds. After fighting with a gas block removal a few weeks ago, I was thinking of putting a good layer of moly grease under the gas block, does anyone do this when installing gas blocks/fsbs? I can't think of any reason not to do it but I have been wrong before.

[SpankMonkey]

Originally Posted by dp0350

I generally just apply moly grease to the barrel and receiver extension threads during builds. After fighting with a gas block removal a few weeks ago, I was thinking of putting a good layer of moly grease under the gas block, does anyone do this when installing gas blocks/fsbs? I can't think of any reason not to do it but I have been wrong before.

It will simply burn off the first time you start shooting the gun. Think lots of smoke.

[dp0350]

Moly grease isn't high temperature? In any case I guess it wouldn't stay around for any length of time.

[jpmuscle]

The moly stuff works ok but I started using the Hi temp permatex anti-seize stuff with great results. Good to 1800 degrees as well. I use on both my pinned gas blocks and barrel nuts.

The copper version would be even better but not necessarily needed in this application

[Markasaurus]

The anti-seize is what i was going to suggest. Its incredibly tenacious, unbelievably sticky too. Again though, temperature may be a problem, it is high temp but can still burn off in the long term anyway. If you anticipate removing the gas block again, I'd dribble some kroil or clp under the block every time you clean then wipe off excess...those two steps ought to keep the gas block from seizing again.

[MistWolf]

I used a little anti-seize on a gas block simply because it made installation easier. Haven't removed the gas block though. The anti-seize helped with the installation and hasn't hurt anything or produced any smoke that I recall. High temp anti-seize is used to install bolts on automotive exhaust systems and does extend the time before the bolts seize due to heat and exposure to adverse environmental conditions

[Eric D.]

I coat the whole barrel, forward of the fsb with moly grease so that the finish isn't scraped up when sliding the fsb on/off. I use the coastal black ford/lincoln/mercury stuff from the auto parts store. FWIW there is still grease on my barrel near the fsb after ~1k rounds.

[dp0350]

That's good to know. I'll give anti seize a try and see how it works.

[donwalk]

i used to use anti-seize on air cooled racing motorcycle engines all the time and never had a problem loosening whatever it was on with.

i don't know about temperature comparisons, but it worked well on the engines.

[jpmuscle]

Originally Posted by donwalk

i used to use anti-seize on air cooled racing motorcycle engines all the time and never had a problem loosening whatever it was on with.

i don't know about temperature comparisons, but it worked well on the engines.

Ill second that, used it on a number of engine related fastners on my zx12r. Also, used it on the connection surfaces on the exhaust from the header to the mid pipe to the can and after 1.5 seasons it held up fine.

[OMD]

I've always used milk of magnesia as it is way cheaper.

[devinsdad]

Interesting tid bit...even with all the high-tech anti-siezes on the market, when installing ignitor plugs in the TF-34 engines on an A-10, we use Milk of Magnesia for the threads. Changed groups in my time in the Air Force, never had a stuck one.

[eternal24k]

I usually put some moly grease under the gas block when installing.