New Build, and off to a bad start.

[SuperHog]

I have removed over a dozen barrel nuts all tight and not a single broken receiver. I clamp the receiver side ways in a vise with plastic sheets on the vise jaws to protect the paint finish.

Use a heat gun on the nut to expand it only and a good nut wrench.

There are no thread locker on these nuts. Just torqued. The black oxide finish on the nut is abrasive and has tremendous holding power once torqued.

[Kos-Mos]

Also removed quite a lot of nuts from receivers...

Anyone ever thought about leaving the mechbox and lower attached???

That is how I do it (with a thick rubber piece on both sides, in a vice), and nothing cracked ever... AND I did have to hammer a wrench to get it started... and it was a KA body..

[OM3GA]

I thought about doing that but I didn't want to take the chance of doing any damage to the lower. I think the real trick is what HKGhost showed, making sure you have sufficient clamping force just behind the barrel nut so least amount of flex happens. Not a bad idea though, as I can see little moving that way. I would rather not involve the lower if I didn't have to though.

I'm still amazed it takes the force it does to get these things off, King Arms really likes their parts tight.

[Wrath144]

Put a vertical grip.... on the top rail?

[ILLusion]

Originally Posted by Wrath144

Put a vertical grip.... on the top rail?

I've seen top rails torn right off the upper receiver by pressuring on the rail.