Jack,
My birdshead Vaquero does roll up under recoil (45 Colt) but it is very comfortable to shoot with
standard smokeless and blackpowder loads. it puts the hammer under my thumb for cocking. It has a 3.5" bbl and it is uncomfortable with full house loads (325 gr @ 1100fps), but I had an extra gripframe fitted just for shooting heavy loads. (its one of my carry guns).With 35 gr BP/255gr loads it hits POA @ 50yds, smokeless hits about 3"low and 2" left at the same distance.In fact I have a stainless Vaquero on order in 44-40 and a birdshead grip ordered from Qualite.