12.5 grendel just born tonight and ready to get some

[A5BLASTER]

A5, did you do anything special to the upper when building like truing up the face or bedding the barrel?

Yes. I lapped the reciver face and did a compression fit bedding with steel shim stock that you can get in a roll.

Bedded the gas tube into the gas block, blocked the gas tube roll pin up so gas couldn't leak through it and hand cycled the action while soaking wet bout 300 times.

Do this to all my ar grendels.

[The Jerry Punto]

A5, how does thermo fit compare to compression fit bedding? is it basically the same concept. also how are you bedding the gas tube?

[A5BLASTER]

A5, how does thermo fit compare to compression fit bedding? is it basically the same concept. also how are you bedding the gas tube?

Thermos fitting is how I get a compression fit.

When I find the correct thickness of shim stock that is just thick enough to keep the barrel from installing into the upper. I then do the heat and freeze thing and that allows it to install.

Once it returns to normal temp it's a super stiff and secure fit, basicly to get the barrel back out I have to drive it out with a wooden dowl inserted from the back of the upper and driven with a hammer.

I use to use locktite to build up a layer so the gas couldn't escape but lately I have been useing grollia glue gel super glue. Tends to last longer then the locktite.

All it does is hold back any gas that could escape from those spots until the carbon builds up and creates a carbon plug.

I put a ring around the gas tube where it comes out the gas block and I also cover each side of the gas tube roll pin (after it's installed)

I let it sit over night and then install the completed gas tube/block assembly onto the barrel.

You would be amazed how much gas comes out those lil spots.

And the glue isn't strong enough to lock up anything that you don't want it too.

[The Jerry Punto]

Ok A5, I'll give that a try on my next build. Thanks!

[Lastrites]

A drop or two of Acetone would break down any super glue if an issue were to present itself as well. Looks like it holds some real promise in the days coming.