I was actually trying that before but while trying to keep my front sight on target I ran into two issues.
1.) I couldn't activate my mag release properly. The angle from a proper grip seemed too troublesome.
2.) While inserting a fresh mag, it almost seemed as if I was upper cutting my mainspring housing and unable to keep my shoulders squared while keeping the mag centered at the base of my palm.
.... Not sure how relavent this is but trust me, I tried duplicating the speed reload scene from The Expensables 20+ times with no success. Freak'n Hollywood movies! lol!