Originally Posted by
coopersdad
I'd appreciate some guidance on how to proceed with my new Ruger Bisley Flattop .44 special. Bore slugs .429. The Oregon Trail bullets I have measure .4316 - 8 on my micrometer and won't fall through the cylinder throats, but will go with a finger push.
I've gotten OK accuracy so far, best groups 2 - 2.5" at 25 yards, using the Oregon Trail 240 gr. semiwadcutters and 6 - 7.5 gr. Unique. Ran out of them, but I have some of their round nose flat point, which haven't been as accurate.
The cylinder and barrel lead badly, it takes a long time to clean, and my groups deteriorate as the session goes on. Since bullet size seems OK, I've attributed this to hard lead and maybe the bevel-base bullets. I'd like to get better accuracy and less leading, so I need a mould. Seemed a good excuse to buy a set of pin gauges to get actual measurements. The results have prompted my questions.
I checked the barrel for thread crush restriction. .417 is a no-go. .416 enters the muzzle about 1 3/4" and stops (2" long gauges). .415 slides smoothly all the way through. So I scrubbed with bronze scrubber and Lyman polishing cloth several times, thinking I'd missed a bit of lead (can't see any). That didn't change anything, so it appears the muzzle end of the barrel is about .001 larger than the rest. I've heard a tapered bore can be good, but pretty sure that's backwards.
In the cylinder, a .432 pin goes through all, .433 won't. The .432 pin actually measures .4318, about what the bullets do.
There appears to be a burr of some sort a two of the mouths. In both, the pin, inserted from the rear, stops exactly at the end. In one I can give it a bit more push and it will go through, but tight. The other won't go past - might if I hammered on it but not gonna do that.
On both, I can see what appears to be a tiny dent, right at the edge, that has pushed a burr of steel into the throat. .431 pin goes through easily, so it isn't very big. I haven't dropped the cylinder or whacked it against anything that I recall, and I can't imagine causing that cleaning.
While a .432 reamer would be the best I'm sure, my initial thought is to remove the burr with a small very fine needle file, very carefully, a stroke or two, try the pin, stop when it passes, then polish a bit with fine paper on a dowel. Bad idea?
Then get a mould that drops at least .432 and see how it shoots with the barrel. It seems to have potential as it is. I don't know if firelapping would even that out? Or is that barrel issue something I should deal with Ruger immediately? I'm new to revolvers, at least getting the best from them, and most of what I know has come from here. Thanks for any advice!