Recut my forcing cones

[hylander]

1873 Uberti 45 Colt. and Single-Six.
Bought the tools from Brownells.
Only took a few minutes each.
The Single-Six cut like butter.
They both leaded up at the mouth of the forcing cone. Hopefully I can give a range report soon.

[DougGuy]

Hey those look great! Check your throat diameters, forcing cone won't cure tight throats, you would still be leading if they are tight.

BTW, FYI, don't try this on a S&W Mountain Gun, I found out from S&W that the 44 Magnum is cut on 8° and the 45 Colt is cut on 10° The reason they are different is that the 44 magnum has a thicker barrel stem and the 45 Colt has a thinner barrel stem so there is less metal removed with the 10° angle, making it safer than it would be on a shallower angle. The 44 magnum firing into an 8° forcing cone would develop less of a pressure spike than a sharper angle would generate.

[hylander]

Hey those look great! Check your throat diameters, forcing cone won't cure tight throats, you would still be leading if they are tight.

BTW, FYI, don't try this on a S&W Mountain Gun, I found out from S&W that the 44 Magnum is cut on 8° and the 45 Colt is cut on 10° The reason they are different is that the 44 magnum has a thicker barrel stem and the 45 Colt has a thinner barrel stem so there is less metal removed with the 10° angle, making it safer than it would be on a shallower angle. The 44 magnum firing into an 8° forcing cone would develop less of a pressure spike than a sharper angle would generate.

Thanks Doug,
Throats are good if not a tad large.
Do you know if it is ok to chamfer a Smith 686 no dash to 11 degree?

[DougGuy]

Thanks Doug,
Throats are good if not a tad large.
Do you know if it is ok to chamfer a Smith 686 no dash to 11 degree?

If I'm not mistaken, that one is already cut on 8° so an 11° cut is only going to affect the first part of the existing forcing cone, it won't reach far enough to clean up the whole thing without dangerously thinning the fire ring at the end of the barrel. You could use the 5° cutter that comes in the Brownell's kit, if it doesn't clean up all the way back to the fire ring, you could use the 11° very judiciously to dress the entrance to the forcing cone.

I also do NOT use lapping compound on the brass lap, I found that instead of polishing, it more often than not just cuts some new "grooves" so I take a small piece (5/8" x 1 1/4") of thin well worn fine scotchbrite, poke a hole in the middle of it, thread it onto the rod, fold it over the brass lap and push it into the barrel, give it a few twists, and it's polished nicely.

[Rapier]

The cylinder chamber throats smaller than the barrel groove diameter is a major deficiency for any revolver, especially with cast bullets. So re-cutting the barrel forcing cone should be step one in a revolver cylinder to barrel setup, to get a revolver to shoot well.
You should also check and then uniform the cylinder chamber throats to be .001-2 over groove.

[hylander]

The cylinder chamber throats smaller than the barrel groove diameter is a major deficiency for any revolver, especially with cast bullets. So re-cutting the barrel forcing cone should be step one in a revolver cylinder to barrel setup, to get a revolver to shoot well.
You should also check and then uniform the cylinder chamber throats to be .001-2 over groove.

All chamber throats are larger than groove diameter.

[indian joe]

1873 Uberti 45 Colt. and Single-Six.
Bought the tools from Brownells.
Only took a few minutes each.
The Single-Six cut like butter.
They both leaded up at the mouth of the forcing cone. Hopefully I can give a range report soon.

I did our capgunz with an 11 degree brass mandrell with emery paper glued to it - they looked good and shoot fine - the cuts however dont look near as deep nor as steep an angle as your pics ? ....maybe its the camera ....maybe I made that mandrell 11 degree included angle not 11 from center ???? ....not going back - aint broke dont need fixin!

Reamed cylinders (.462) to 2 thou over groove (.460) and ball (.464) is + 2 over cylinder. ....(round ball gunz)

heap BIG difference in accuracy with full cylinder of powder ----

I think shoot em with target load (semolina over powder) the filler takes up windage and stops gas cutting the ball but with cylinder throats at .452 and groove .460 ? heck of a lot of obduration required

[Bazoo]

Looks like clean work. I have found you can use sticky back sandpaper on the brass lap and use that to clean up the cutter marks. I used 600 grit because that's what I had handy.

[pdgoutdoors]

That looks clean. Any range report yet?


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[hylander]

That looks clean. Any range report yet?

Sent from my iPhone using Tapatalk

The Single-Six is great, no leading and accuracy is a little better, no flyers.
The Uberti is better as far as leading at the forcing cone. Still getting some leading after the forcing cone.
However, the bullets I have are under sized.

[Bazoo]

The Single-Six is great, no leading and accuracy is a little better, no flyers.
The Uberti is better as far as leading at the forcing cone. Still getting some leading after the forcing cone.
However, the bullets I have are under sized.

Thanks for the update.

[Rapier]

The leading on cast after the cone is probably gas blow by cutting at the bullet base from the bullets being undersized, as you noted.