Help needed with a P* DMR

[Snakeeyes75]

Hi all, I've taken the plunge and bought myself a P* Jack unit. I've used a G&P V2 gearbox shell and fitted it into a VLTOR/Magpul Receiver. Here's the problem, when I tighten up the grip and the stock (Again, both Magpul) it twists the gearbox to the left so the nozzle rubs on the hop rubber.

 

For those that haven't seen it, here's the gun I'm blatantly copying:

 

 

I realize he's using a P* Fusion Engine. I have no clue what to do to sort the issue

 

Is this problem common to building guns?

[Rock-climby-Dave]

fit pistol grip first, then stock.
Iuf that doesn't work fit it like this:

 

Box into lower receiver

Pistol grip on

Upper and llower together

Stock on

[Mr Monkey Nuts]

I have had to shim with some penny washers in the past.

[Snakeeyes75]

After an afternoon of f*cking about, I'm going to have to shim it somehow. There's a small chunk missing out of one of the rear body pin holes so when you nip up the grip and stock it bends the gearbox to the left (Selector plate side)

[Snakeeyes75]

I have had to shim with some penny washers in the past.

 

After about 6 hours of scratching my head I ended up putting 2 washers on the left side of the grip and half a washer (Cut down the middle) on the rear of the gearbox. Now when it's all tightened up it pulls straight I didn't realize gearbox alignment shimming was a fairly common thing!