picked up a couple more spr shotguns today a spr 453 auto loader and a spr 310 O/U both in 12ga, i already have a 453 and really like it, i use it when i dont want to drag a browning or one of my nicer remingtons through the mud, works great...anyhow they do not use stadard Rem chokes (at least time dont seem to fit) does anyone know what kind of chokes fir these 