Backstory:

During the "panic" I purchased one of the last of what I would consider "decent" rifles I could find on a shelf within 50miles of me.  A Smith and Wesson M&P15OR.  You may know the OR has a railed gas block.  I wanted to install a low pro gas block so I could install a DD rail.  Removal of the factory smith gas block proved impossible.  Tried everything I could think of.  Torch, lube, press, etc. (and yes I was attempting to hammer it out the correct direction).  I ended up taking a cutting wheel to the gas block and cutting it off, I then used a grinder to grind the pin down flush with the barrel, leaving it in place.

I now have a clamped on DD gas block and a DD rail protecting it.  I had to adjust the gas block initially because it didn't cycle properly on my first attempt, but I got it adjusted and have put a few hundred rounds through it in the last two years that I've had it without any issue.


My issue is that I'm not sure I trust just a clamped on gas block.  This is currently the only fighting rifle I have.  I don't have a lot of cash to work with, so I would like to avoid spending more money if I can.  Initially I was just going to buy a used barrel with a pinned standard front sight post and then just install it and cut off the front sight post.  However some reading has me wondering if I could get by with my current set up if I just tweaked it a bit.  I did not loctite the clamp screws, so I will use red loctite on those, and I have heard of people bedding the gas block with a small touch of green loctite to mate the gasblock to the barrel (but this doesn't add up because heat breaks down loctite and green loctite is only good for about 400 degrees IIRC)


Looking for advice or suggestions from people with more experience than me.

Rocksett

Your clamp on gb should be fine.  I have used them on all of my builds and have had no issues with them loosening.  Unlike you, I was able to remove the railed gas block I had on a SIG M400, and it was replaced with a clamp on gb...

I am noob in this area.  Talk to me like I'm Joe Biden.  Rockset is a substitute for loctite on the clamp screws?  Or use rockset to bed the gas block?

Thread locker. Great stuff

as with AlabamaPaul, I've had no issues with them loosening. I just wanted to let you know that there is an alternative to loctite that can take the heat.
I would try it as a bedding. but, if you ever want to remove it. I would use just a tiny drop on the screws if any. because they are so small

Thanks for the replies


So am I worrying for no reason about the longevity and reliability of a clamped on gas block for a fighting rifle?  This is not a plinker.  I purchased this rifle to fight with.

If it is covered by the hand-guard, it is highly unlikely it will ever loosen or be knocked out of line.

I can't honestly say: no reason to worry. Murphy's law and all. closest thing to sure, would be pinning it. ADCO provides this service.  but like I said, I would try bedding it with the Rocksett. I may still do it to mine. they sell a larger bottle of it at that link

I think I'm going to bed it with rocksett and then stake the screws.  Should be pretty solid after that I would think.

Rocksett is good stuff, however, I have never used it on a clamp on. A dimpled barrel with set-screws would be best,IMO. The bedding idea might work though.

These days most of my gas blocks are the clamp on type.
I use barrel assembly grease and the proper torque as a thread locker.
If after two years of use you still don’t trust your setup get it pinned.
Gas blocks don’t need to be bedded.

A LOT of clamp on gas blocks have been sold, installed, used..

you would know if there were issues with them by now if there were any.



that being said, I prefer set-screw type of gas blocks used in conjunction with barrel dimpling.

I have never pinned a gas block myself, but several of my off the shelf barrels have had pinned gas blocks.
(which is my default option if it's "easy" when I'm purchasing a barrel.)


my order is:
pinned
then
set screw
then
clamp on


but again, if there were issues with clamp on gas blocks.. you would have heard about them by now.. (on the market for MANY years and probably tens of thousands of them in use)