Doesn't fit like the gen 1 - Strike Industries AR Enhanced Castle Nut / Extended End Plate

I have the Gen 1 on my rifle, and I got this gen 2 for a pistol build. I think it's thicker than the gen 1 and it takes up more space so Im not able to thread the buffer tube into the receiver far enough to catch the bolt retainer before it bottoms out on the tube. Definitely looks cool though on the Internet though.