Back in the days, on my Diesel Submarine, we had a gun locker full of "28's and M 1 Tommy's. I remember the stocks wobbled on the 28's and the M 1's were mint (like new). Later in 1967 on my first (only) nuke missile Boat, we still had a locker full of M 1 Tommy's. All of my boats had 1911's and a few Garands. IIRC, in the Thompsons we used 20 rd mags. I really loved the M 1, heavy but most comfortable and comforting. Go to youtube and check out USS Wahoo in WW2 and see what a Thompson and B A R could do to " Remember Pearl Harbor".