I sent you an e-mail, but I'm not sure if you received it. I recently purchased a Bushmaster Shorty carbine and it appears that the magwell is milled out of specs. It will only take 3-4 of my USGI mags w/out meeting resistance in inserting/removing them. It appears that the right side (as viewed from the top of the lower receiver) of the magwell is milled at a slightly rounded angle instead of being flat. If I send in the lower receiver can it be milled/refinished to correct the problem?