AR15 gas block will not stay clamped

[orygun]

Try as I might (for the sake of my wife) to keep my gas block clamped, there's little I can do about it once I fall asleep.

 

[HuckFin]

Thanks everyone for the advice. I still haven't heard back from SAA but am going with a Yankee Hill steel gas block (YHM 9390A) that will work with my YHM handguard and give me a sight base and sling mount.

 

[Tomahawk67]

You'll be wondering why you waited until now , and have the satisfaction of fixing it yourself. Good to hear.

 

[HuckFin]

As much as I hate to admit this, on the last aluminum gas block I bought the threads were not stripped and the gas block was still tight. The problem was me... The Allen wrench I was using was twisted and slipping and since I had the screws pull out the threads on the previous one I thought I was having the same problem again.
So I am going to stay with this aluminum one. If I ever have any problems with it I will report back. I have had several hundred rounds through it so far mounted on an 8" barrel.

 

[HB of CJ]

Let's try to keep this thread going. Good stuff. It is important what exact kind of Allen head screws the gas block manufacture is providing. The bolt threads must exactly match the gas block threads. Several, (a few?) different pitches and numbers of threads are now available. All different.

Same thing with that Allen head. Metric?, SAE? Something yet different still? It is fun and easy today to gather up all sorts of slightly different Allan head screwdriver kits. Like all ready found out, the Allen head wrench must exactly fit the screw head and the screw threads must exactly fit the gas block.

Quality of nowadays available AR15 front gas block assemblies.

1) Best. Forged or machined STEEL front gas blocks held in place by the two, (2) OEM steel taper pins.
2) Next Best. Steel gas blocks held in by at least two, (2) and maybe three, (3) Grade 8 Allen Head Screws. Both sides threaded.
3) Kinda OK. Steel gas blocks with just two, (2) Grade 8 Allen Head Screws with one side of the block threaded
4) Least desirable ... Any type of Aluminum AR15 front gas block. The OEM gas tubes are high temp Stainless Steel for a reason.

All Respectfully. Hundreds of AR15 builds. Uncounted M16 rebuilds.

 

[DirectDrive]

Stay away from aluminum gas blocks.
You have the dissimilar metals thing going on.....that's a negative
Aluminum and steel expand and contract at different rates.....another negative
Aluminum is less resistant to erosion....yet another negative
Alu GB's are usually offered by marginal, low-end companies that are good at selling crap.

 

[HB of CJ]

Yep.

 

[jbett98]

I find that grinding down the end of a used Allen wrench a little bit sure helps it grab the sides of the screw real tight.

 

[Mygrainman]

Try as I might (for the sake of my wife) to keep my gas block clamped, there's little I can do about it once I fall asleep.