Hi, been reading ar15.com for a few months now as I decided to build an ar. Picked up a Roggio Arsenal stripped lower at a gun show a little bit back. Ordered a DPMS LPK and DPMS Pardus stock (which seems to be advertised everywhere as a 6 position stock but seems to be 4). The LPK went together great, mostly from the great guides around here. I made it with a bare minimum of scratches and mare marks, and almost exclusively used the tape+vice grips method.

But then I got to the stock. After about a full turn  trying to thread it in,  it gets extremely tight, to the point it won't thread anymore. I tried lube/CLP/ etc... but the thread size just seems to be off. I was wondering if this is a known issue with either the Roggio lowers or the DPMS stock and what the appropriate course of action from here would be. Any help is appreciated, even though you guys have already helped me so much.