RE: Springfield XD 45 ACP- I shot mine!
Your dad is spot on. 1911's have a longer, less steep feed ramp. You father's is probably polished smooth as butter too. The glock's and glock-a-likes' ramps are steeper and most likely unpolished. A dremmel tool and some polishing compound could slick up the ramp and you may cure the loading issues. Or you can simply use round nose ammo.