I'd say keep shooting it, practice, practice, practice. Work on your form at the bench?
Steve
Well, I had three reasons to think I had a restriction where the barrel meets the frame, before I started firelapping.
1. Visible leading started in the barrel just outside the frame.
2. I could "feel" the restriction start in the same spot when pounding a barrel slug through from the muzzle
3. With the Lewis deleader screwed down as tight (as big a diameter) as possible to still get through the breech end of the barrel, it would leave lead behind once it got through the restriction at the frame and out into the barrel proper. Gets a lot easier to pull on too ;-)
At this point my barrel slug measures .4525 and my cylinder throats were opened to .4525 by cylindersmith. So when I fire a .453" bullet it is getting swaged down to .4525 in the chamber throat, passing through the forcing cone and breech end of the muzzle, and then maybe kinda sorta keeping a little bit of grip on the rifling once it gets out into the open part of the barrel.
One thing I am going to try is run some soft lubed lapping bullets (nearly pure lead, BHN about 5), with no lapping compound in them, just my soft home made lube, at a high enough velocity that they ought to obturate once they get to the open part of the barrel and see how they group.
I am likely to melt some of the crayon lube out of my RimRock 270-SAA and home lube them myself next time I lube a pan of bullets. They are advertised BHN = 15 and diameter =.452. They measure .454 and .455, and I am pretty confident I am not driving them fast enough for the lube to work very well - and they lead like some quaint expression I haven't heard before that probably isn't safe to use in mixed company.
I do have some H-110 left, I may very well run some of the 270SAA with the crayon lube at ~30k pressure just to see what I get.
Considering my group size was the same with 230gr at 700fps and 270gr at 1000 fps, no statistical difference, I feel pretty good that currently I am shooting at least as well or better than the gun is shooting. The good news is my hunting buddy should be home from outside in the next week or so and wants to shoot it. I have been at the range with him when he has grouped 6/6 out of his .44magnum into a paper plate at 100 yards, I am mildly curious to see what groups he can get out of my gun at 25 yards, but I am not holding my breath.
I do keep in practice with a different revolver that groups pretty good.