I just recently purchased micarta for my 16. I had to take it back. I had planned on using stainless as I normally do and I had the same problem. Tried every trick in the book to make it work. Stock hardware would not work, also. I sent the micarta back and they ended up taking the rest of the tweener micarta off the shelving (they had quite a bit of it along with the larger ones for the 2,9, etc.). The ones I returned were kind of green if you use your imagination. They had one set left in the more brownish range that they said would work. I accepted that, few days later they arrived and fit fine.
The holes are not deep enough, I ended up stripping a screw also. It would just catch the threads and I thought I had it started but ended up stripped.
I would return it and wait for a proper replacement. I have 3 other sets of tweener micarta scales and have never had a problem.