akajun
08-08-2010, 05:17 PM
After dealing with leading for years in my .38 revolvers, I finally decied to do something about it. Currently I have 5 S&w 's of various models and one Colt Official Police from the 30's. All leading was just forward of the forcing cone which told me it was a bullet size problem.
First Ill start off with My m10 heavy barrell from the late 70's or early 80's. This is a Police turn in that was in sad shape when I got it and had been heavily used. It had excessive headspace to the point where It would misfire at least twice per cylinder and there was no bluing left. Clarks took care of the bluing and I refaced the yoke and added some cylinder bushings to fix those problems, then re cut the forcing cone to 11 to clean it up. It is a great little pistol now, but still leaded at the forcing cone no matter what size bullet I used . A check with my pin gauges showed all throats to be .356 and a slug showed .357 in the bore.
Next is a m66, also a police turn in, but this one was a desk jockeys cause it had hardly been fired. However again it also leaded and also had .357 bore and .356 throats.
Next is a 586 from the early eighties. This gun was new and was the worst leader of them all. A .3565 bore and a .355 throats, also the throats were very rough, with spiral lines in them like they had been drilled with a drill instead of finished reamed.
Next is a model10 snub nose from the 50's, which measured .357 bore and . 357 throats. It barely leaded.
Next is a Combat Masterpiece wich never leaded, no matter what I shot. .357 bore, and .358 throats.
Last is the Colt Official Police. This also never leaded. .356 bore and .358 throats.
I purchased the Manson reamer and bushings from brownells and went to work. It was very easy to do and I did all my guns in under 30 minutes. The Combat Masterpiece and Colt, no metal was removed at all and they reamer just pushed right through.
Of special note was the model 10 heavy barrell. When reaming the cylinders, noticed it was not removing metal from the cylinders evenly, rather there were "high spots" in the thoats that the reamer shaved off. I also showed the rough machining that the 586 showed.
Also the 586, since the throats were so tight, the reaming reomved all the tool marks, leaving nice smooth throats.
Conclusion: Now that all throats are .358 as per my pin gauges, no revolvers at all lead. I do not notice an accuracy improvement, but I have not realy tried to go for that, as I was mostly interested in stopping the leading. I would recomend doing this to your wheelguns. The older guns with the .358 throats as from the factory also confirm this.
Observations: Older S&W's and the old Colt seem to have been better machined in the throats. I find it odd that all guns had essentially the same bore size, but the throats varied so much. The guns from the 80's seem to have been the worst. It seems like S&w was trying to get the last drop out of the throat reamers by using well worn reamers and reamers with chipped teeth which gouged the metal.
I do not know what caused the high spots in the m10 throats, a wobbly reamer or just the years of hard use.
**Update, I pin guaged my ruger Blackhawk in 41 mag and discovered 4 cylinders in .410 and two in .411. When shooting the hand cannon, I always got two fliers in my groups, I wonder if this was why? However I could not find a "piloted cylinder throating reamer". After much searching, I discovered that Enco sells a carbide tipped chucking reamer in .4110 for $65 or so. Always being one to buy the tools instead of paying someone else, I bought it.
Upon its arrival, I took a fired and unsized. case and drilled out the back of it to accept the reamer and reamed the inside of the case, making a guide to protect the rest of the chamber. I then inserted the case in each cylinder and reamed all the throats to .411. by hand. Since only .001 was removed, it was very easy.
First Ill start off with My m10 heavy barrell from the late 70's or early 80's. This is a Police turn in that was in sad shape when I got it and had been heavily used. It had excessive headspace to the point where It would misfire at least twice per cylinder and there was no bluing left. Clarks took care of the bluing and I refaced the yoke and added some cylinder bushings to fix those problems, then re cut the forcing cone to 11 to clean it up. It is a great little pistol now, but still leaded at the forcing cone no matter what size bullet I used . A check with my pin gauges showed all throats to be .356 and a slug showed .357 in the bore.
Next is a m66, also a police turn in, but this one was a desk jockeys cause it had hardly been fired. However again it also leaded and also had .357 bore and .356 throats.
Next is a 586 from the early eighties. This gun was new and was the worst leader of them all. A .3565 bore and a .355 throats, also the throats were very rough, with spiral lines in them like they had been drilled with a drill instead of finished reamed.
Next is a model10 snub nose from the 50's, which measured .357 bore and . 357 throats. It barely leaded.
Next is a Combat Masterpiece wich never leaded, no matter what I shot. .357 bore, and .358 throats.
Last is the Colt Official Police. This also never leaded. .356 bore and .358 throats.
I purchased the Manson reamer and bushings from brownells and went to work. It was very easy to do and I did all my guns in under 30 minutes. The Combat Masterpiece and Colt, no metal was removed at all and they reamer just pushed right through.
Of special note was the model 10 heavy barrell. When reaming the cylinders, noticed it was not removing metal from the cylinders evenly, rather there were "high spots" in the thoats that the reamer shaved off. I also showed the rough machining that the 586 showed.
Also the 586, since the throats were so tight, the reaming reomved all the tool marks, leaving nice smooth throats.
Conclusion: Now that all throats are .358 as per my pin gauges, no revolvers at all lead. I do not notice an accuracy improvement, but I have not realy tried to go for that, as I was mostly interested in stopping the leading. I would recomend doing this to your wheelguns. The older guns with the .358 throats as from the factory also confirm this.
Observations: Older S&W's and the old Colt seem to have been better machined in the throats. I find it odd that all guns had essentially the same bore size, but the throats varied so much. The guns from the 80's seem to have been the worst. It seems like S&w was trying to get the last drop out of the throat reamers by using well worn reamers and reamers with chipped teeth which gouged the metal.
I do not know what caused the high spots in the m10 throats, a wobbly reamer or just the years of hard use.
**Update, I pin guaged my ruger Blackhawk in 41 mag and discovered 4 cylinders in .410 and two in .411. When shooting the hand cannon, I always got two fliers in my groups, I wonder if this was why? However I could not find a "piloted cylinder throating reamer". After much searching, I discovered that Enco sells a carbide tipped chucking reamer in .4110 for $65 or so. Always being one to buy the tools instead of paying someone else, I bought it.
Upon its arrival, I took a fired and unsized. case and drilled out the back of it to accept the reamer and reamed the inside of the case, making a guide to protect the rest of the chamber. I then inserted the case in each cylinder and reamed all the throats to .411. by hand. Since only .001 was removed, it was very easy.