Solved: New Grendel build will not lock bolt back

[Dt219]

[Dt219]

Problem found, LOOSE GAS KEY

[VASCAR2]

[Klem]

Dt,

Is the carrier key staked?

Are you going to fix it yourself or return it?

[Dt219]

It was staked and it looked to me like it was good but I guess not. I took the key completely off, cleaned it spotless, and make a thin blue locktite gasket and a drop on the bolts. If I can come up with a good way to stake it I will do it

[Klem]

Dt,

Fair enough.

For the sake of only one carrier it doesn't make sense to purchase the $70 Brownells jig. Staking from the top is a recognised method however. For this you only need a chisel and a hammer, so no financial outlay. I hear this was the original method used before the 'Revised' method replaced it (coming in from the sides). I am sure you know the drill. Just enough to stop the screws moving and not too much to break them.

I hear some manufacturers of cheap carriers don't bother putting a gasket seal around the flat of the key. The time I did three of these jobs we used Selleys Liquid Gasket to seal the bind. It's a silicone rubber for car engines. I am sure your Loktite gasket will work also.

[LRRPF52]

Use US Grade 8 fasteners torqued to 55inch-pounds.

Colt Armorer/Depot Maintenance and Repair Manual, No. CM102 dated 1991, specifies Permatex #3D Aviation form-a-gasket as a sealing compound for the carrier key.

[LRRPF52]

You can use the OCKS Carrier Key fasteners as well, which really help prevent fasteners from ever backing out.

Loc-Tite vs Permatex, Thread Sealant and Threadlocker Comparison

Some companies use Red Loc-tite 272 or Permatex Red sealant, both of which are high strength.

The Aviation-grade Form-A-Gasket is meant for sealing two pieces together like that.

A weakness of the AR15 carrier and carrier key interface is that the fasteners are located to the rear of the gas hole, so torque is applied and maintained behind the hole, not on both sides of it.

POF actually made a carrier and carrier key that dovetail together and only use one fastener to deal with this design feature of the standard Mil-Std configuration.

[Mad Charlie]

LRRPF52:

Thanks for that info, I haven't had any issues yet, but I am going to change out at least one of my gas keys for a RCA key shortly.
I like using new fasteners for such jobs as this.

[Old Bob]

LRRPF52:

Thanks for that info, I haven't had any issues yet, but I am going to change out at least one of my gas keys for a RCA key shortly.
I like using new fasteners for such jobs as this.

I got my OCKS carrier key screws from this vendor. They have some nice pics of the screws so you can see how they function...

https://www.forwardcontrolsdesign.com/OCKS_p_149.html

I had a loose carrier key on a M4 carbine. The key looked like it was staked before the screws were torqued. I replaced the key also & used the 3D aviation form-a-gasket as well.

[LRRPF52]