I just bought a new Blackhawk, 45 convertible, and can’t shoot my favorite loads in it. I like shooting a LaserCast 300gr. in my Vaquero. It is loaded and crimped on the bottom crimp groove making the oal right at 1.64” When I tried them in the BH the rounds wouldn’t chamber all the way in. They extend just far enough to rub. I did some checking and found that all of the chambers, up to where the throat starts, were .03” shorter on the BH than on the Vaquero, just enough shorter to prevent chambering the round. The throat being .4521" the bullet won't enter the throat without a lot of urging. In other words the Vaquero chamber is long enough to contain the shell and bullet but the BH is short enough to force the bullet into the throat if the shell is chambered all the way. I am a little leery of loading that bullet to the top crimp groove as my oal would be in the neighborhood of 1.57” to 1.58” with a healthy dose of H-110 behind it. The load is high pressure as it is and I’m afraid of pressure rising by seating the bullet deeper. Has anybody else come across this situation and if so what have you done to correct the problem? The only solution I’ve come up with so far is to limit my loads to 255gr. (which I really don’t want to do) or ream the cylinder so that I have a little longer length. I am open to suggestions.