Got one of those NCStar buffer tube jigs in after reading all the praise on here about them. Tried a couple of different lowers (SOLGW/Aero/Del-Ton/PSA/etc.), and when securing the lower to the jig via the pistol grip screw, the buffer tube is way off axis with the jig. Seems that the geometry is off in the angled portion of the jig where it interfaces with the pistol grip tang on the lower.

Anyone else run into this issue with theirs? I contacted NCStar. A week later, they replied and said that it would still work, but I could send it back to them on my dime if I wanted to. Not sure how it would work when the rear ring assembly is parallel to the rest of the jig, but the buffer tube is not. How am I supposed to secure the top ring half when the tube is at such an angle?

Overall they were pretty useless. It would cost almost me half the price I paid to send it back to them. You'd think they'd be itching to get it back to determine if tolerances were off in a certain batch, and relay that to the manufacturer. They didn't seem to care.

Can't see why that would matter since it is only trying to limit rotation. The back piece can easily lean to the angle of the tube. Also I would put the level on top the lower not the tube to make the comparison since the nut, lower threads, and tube threads can cause the tube to be off when tightened.

The other level was placed on the buffer tube because the rear assembly that clamps down on the tube is supposed to be parallel to the jig. The rear assembly is supposed to snug down with the thumbscrew and is not designed to tilt.

On mine I don't worry about it if it is level or not.  It keeps the tube from rotating when you tighten the castle nut, nothing more.  It cannot cause the tube to be canted up, down, or sideways and if it is, then the threads were not cut correctly on your receiver.  All I ever do is snug up the screws on the receiver extension holder and tighten the castle nut.  I have done dozens of them and have not had that first problem.  All this worry about shimming the rear piece to be perfectly in line with the lower holder is a bunch of people looking to make mountains out of molehills IMO.  The buffer tube holder doesn't even need its screws to be that tight to keep the tube from rotating.  Much ado about nothing IMO.

The only thing I did do to mine is buy make longer screws and add knurled nuts to clamp down the buffer tube holder and to tighten the holder to the lower.  That way I don't need wrenches.

To me the bottom rear tower screw is just there to keep the two pieces together. I worry more about it not pulling down on the tube by being too tight and only tighten the top clamp. I don't care if the rear tower moves up or down a little if it needs to. Only thing I changed on mine is a U shaped shim on the bottom sides of the rear tower for side to side tilt movement and I shim the gaps out of the upper bottom sides where the bottom of the tube is to limit the rotation.

And I thought I was the only one

Fair points all around. Now I'm wondering why that top ring half is even part of the design if the bottom part of the rear piece is all that is needed to prevent canting.

I’m sure it’s an optical illusion but your lower looks lvl and then the tube looks like it’s canted up.

I barely tighten the grip screw.  I snug down the RE clamp and that’s all it needs. I never understood the people saying they stripped the threads on the jig because there is absolutely no reason to tighten it more than just snug.

I figure it all helps the stability of it. Nothing wrong with using the bottom tower screw but I wouldn't do more than barely tighten it or even run it up against the bottom of the jig until the top was where I wanted it and the two screws snugged.

I agree here.  Out of curiosity,  throw your levels on the buffer extension and the flats of the receiver

It was definitely an optical illusion. Here is a pic of the same lower, with the same levels, with the other level on the flats. Perfectly level. The jig is the issue here.

Mine was also slanted at first when tightened down but I added washers to rear support to raise it up to make it perfectly flat. I also added some adhesive foam neoprene where the grip area is recessed to hold it up & away from block to make for perfect installs.

My problem is, I can’t for the life of me get the grip screw mount to go in.

First one I tried stripped the grip screw threads.  One day I guess I’ll get a machine shop to tap it to the next size up & just drill out the grip if necessary.

I still use it, but don’t use the screw.

There was a thread a while back with the AR-15 Tech dude, who is awesome, and I believe it was him who posted how the hole should measure, but you can’t see the pictures anymore.

I probably need to return it, but want to make sure something is off first.

Maybe not worth your time and money to ship it to me to check it. Im in Georgia.

My issue is that the part of the jig where the pistol grip tang interfaces has the wrong geometry--not the rear support. "Chabuduo".

I will probably just get the Botach jig and do the two-penny vise trick that was in the SOTAR video.

On the upside, this NCstar jig will make a pretty neat paperweight.