I have used IMR4227 and H4227 in a lot of different calibers with fine results. Please note that they are not interchangeable as to loading data.
These powders leave a lot of residue in the barrel because only about half of it burns in the short handgun size barrels. This residue will not hurt the barrel in any way as far as I can tell. When I got my first 44Mag in 1973, a 4in M29 S&W, I shot 200 to 300 rounds a weekend through it using a 250 cast bullet and 23.0 grains of IMR4227. This load gives about 1150 in a 4in barrel. This went on for a year. The bore looked perfect with no erosion. I traded the gun in for an 8in M29 and the dealer said it looked like a new gun.
The only problem with these powders is that some double actions can build up fouling under the extractor star which can make the gun hard to open. This is no problem with the single actions.
With cast bullets there is less leading also because the powder burns cooler. I have seen barrels used with a lot of heavy Unique powder loads that were washed out at the forcing cone.
These powders leave a lot of residue in the barrel because only about half of it burns in the short handgun size barrels. This residue will not hurt the barrel in any way as far as I can tell. When I got my first 44Mag in 1973, a 4in M29 S&W, I shot 200 to 300 rounds a weekend through it using a 250 cast bullet and 23.0 grains of IMR4227. This load gives about 1150 in a 4in barrel. This went on for a year. The bore looked perfect with no erosion. I traded the gun in for an 8in M29 and the dealer said it looked like a new gun.
The only problem with these powders is that some double actions can build up fouling under the extractor star which can make the gun hard to open. This is no problem with the single actions.
With cast bullets there is less leading also because the powder burns cooler. I have seen barrels used with a lot of heavy Unique powder loads that were washed out at the forcing cone.
