I recently purchased a couple of 20 round magazines from a local gunshop. They had Brownell's labels on the package with stock #687-015-020. They have a steel body with polished, black oxide finish made by S.L. SMITH & ASSOCIATES, INC. They feed ok, except sometimes the bolt won't fully feed the first round out of the mag and the last round never feeds properly. The bolt is always held back with the last round hanging loose in the receiver. I was wondering if anyone else has had these problems with this particular manufactures product and if there is anything I could do to get these mags working properly. I also have 2 USGI mags that function perfectly, so I don't think it is the rifle, or atleast I hope it isn't. Any help I could get would be greatly appreciated. I am new to AR-15.com, as I have just purchased a DPMS a few weeks ago, and am greatly impressed with the amount of knowledge that I have gained from you guys since joining.