10 round AI mags will increase his capacity. All of the DBM i listed takes AI mags or Alpha industries mags, which are shorter than AI mags but have the same in some cases more capacity. Though lately Alpha industries has had some QC issues.
"Combined synergy of a man and rifle is matchless, the steadiness of hand and acuity of vision, and finally the art of knowing how to make the rifle an extension of the body, all equate to the ultimate synthesis of man and machine."
"Death smiles at us all, all a man can do is smile back."