chiltech500,
THose pictures were taken using a borescope I had the use of for an afternoon. It would be great if I had one all the time but I simply don't have the money for it to simply sit on the shelf most of the year and only use it once in a while. It just so happened I had been to the range the day before and knew those barrels would be cool to take pictures of for reference later on.
As to the actual leading, the first pic is of my 41 Magnum the second of my 45 Colt, both Redhawk's with 7.5" barrels. With the 41, I had had some very nice results with some hollow pointed cast bullets in the 45 so I figured I would try that alloy out in the 41, I loaded them up incrementally from around 1000fps up to just over 1300 where I got the results you see above. Thing is I knew I would probably get it, I just didn't know where, so it was simply a more or less experiment to find out. Shooting over 20 rounds loaded to right at 1200'ish fps will do the same thing, but dropping them down to 1100+/- 50fps will let me shoot them all day long. But dropping them into that range with that particular bullet don't give the end result I was looking for.
With the 45 Colt, I use two or three different alloys depending on what bullets I have loaded. That particular weekend I had shot up a bunch of different loads mostly just punching holes in paper, and I had run alloy hardness from around a 8-9 up to just over 14. WHile that might not seem like a big variance, it really is considering that the softer alloy loads are running in the 1100fps range. That is why your seeing the little bit of lead laying along the sides of the lands. If I stick to alloys harder than 10bhn, it nearly always looks like a pristine cleaned barrel, well with a little soot from lube and powder.
While I do not look for loads which are listed as "Ruger Only", I have, more or less, cut my loads down to using only Unique, HS-6, and AA-9, depending on just which alloy or bullet I am loading. The loads using the HS-6 were picked up from the excellent write up by John Linebaugh in his 45 Colt Dissolving the Myth. He listed the load at the bottom as one of his personal favorites and once I tried it, I knew why. There is also some great load data for the RCBS 270 SAA in a pdf file from Handloader Magazine written by Brian Pearce which listed a good number of loads for the Colt in different pressure ratings depending on what type of revolver you might have. Most, if not all of my loads, stay within the first and second tier listings in that data. I have simply found no reason to exceed this area as I get all of the penetration and expansion I could want or need. The trick however is keeping the loads matched to the alloy as seen in the pics. Besides if I want more power in a 45 I go to the 454....
As for your issues, yes you should address the size differences in your cylinders. This is a big time cause for leading if your squeezing the bullets down first in order to get out of the cylinder and then they have to expand to fit the groove diameter of your barrel. There is not much sealing going on there, and what remains is the results of that. Having the chamer mouths of your cylinder just a touch larger than your bore isn't AS big of an issue depending on just how big they actually are. If your shooting low end loads (700-900'ish fps) you will probably only see an accumulation around the forcing cone and slightly inside. This can also be addressed by having the forcing cone reamed to a slightly different taper. The other way around you will see plenty of lead stretched down your bore starting at the forcing cone and gradually moving down as the number of shots increase. If your having a lube issue this will usually manefest down towards the muzzle as the lube runs out or gives way to the friction of the barrel.
You are right in there are no real short cuts to getting the lead out. However it can be minimized by simply running the brush through on a regular interval of say 20-30 shots or when you first start to see the build up. When I was working up loads, I would shoot one or two cylinders, then open it up and slip a piece of white paper in against the frame so that I could use sunlight as I looked down the bore. This will light it up plenty good to see even the slightest differences along the bore. If I saw nothing that looked to me like a build up I went on ahead with some more rounds. I use this all the time and when I DO see something I don't like I start scrubbing. For the most part I use the bronze brush, and follow up with about a 1" square piece off Birchwood lead cloths and a tight fitting jag. I have to mention however these aren't supposed to be used on blued guns as they can remove the blueing. Even so using a little Hoppes mixed with some Kroil will get up and under most lead deposits pretty quickly and with the Chore Boy brass pad, most if not all will come out with little scrubbing. Even that in the 41 pictured above only took about 30 minutes from start to shiny squeeky clean.
Hope this helps.
