I have the same problem bit frustrating they don’t warn us before we buy the product. I called veriforce tactical and the said to file down the inside of the knob which helped a bit. Filed down a bit of the charging handle to I wish I never did, scratched some paint off and still didn’t fit perfect so I hammered this junk on and now it’s stuck. Looks pretty decent tho, didn’t even have to screw it tight. Imma shoot it it falls off.