Forcing cone angle

[jrm53]

About 24 years ago I did some barrel replacing with bull barrels and I had poured a cerrosafe casting of the forcing cone on model 10's 65's and cut my barrels to the angle that the casting checked on a comparator, now if anybody knows the included angle would you please post it here. I did not note the angle in my book that I kept. (15 deg on each side would = 30 deg. included) Thanks for your help! Jeff

 

[diamonback68]

11 degrees sticks in my mind, but I could be wrong. Maybe the experts will chime in here.

 

[Snapping Twig]

I know only that S&W cuts the cone at 18* and for cast lead I get them recut to 11*.

 

[tomcatt51]

I would bet you were cutting an 11 degree forcing cone. That's pretty much the norm for the typical PPC HB wadcutter guns.

 

[Tyrod]

You might find this article interesting.

Revolver Muzzles and Forcing Cones

 

[ColColt]

I just had my old Ruger GP100 cut to an 11 degree angle as it looked like they cut the forcing cone with a rusty auger and it was leading at the beginning of the rifling for about 3/4 "-not so much the forcing cone itself, but the grooves looked like they had a step in them and wasn't smooth in the transition to the forcing cone. It looks better now that I've had that smoothed up. The 11 degree cut is primarily for shooting lead bullets where it shines. Ruger cuts theirs with a factory 5 degree angle-mostly for anticipated jacketed bullets.

Before...

After...

 

[Tyrod]

I just had my old Ruger GP100 cut to an 11 degree angle as it looked like they cut the forcing cone with a rusty auger and it was leading at the beginning of the rifling for about 3/4 "-not so much the forcing cone itself, but the grooves looked like they had a step in them and wasn't smooth in the transition to the forcing cone. It looks better now that I've had that smoothed up. The 11 degree cut is primarily for shooting lead bullets where it shines. Ruger cuts theirs with a factory 5 degree angle-mostly for anticipated jacketed bullets.

Before...

After...

I rekon your gunsmith experiences have gone a bit like mine. That first pic is yummy. I feel like this. Bits get dull. Sometimes it's hard to predict when a bit will go past it's expiration date. Sometimes some noob or some untrained person might ruin your tool before you even know it. If I were a gunsmith, and I found my tool was bad. Even if I had to make my customer wait till I could get a replacement, I would not let a gun shown in the first picture out of my shop. I'd overnight the tool if I had too. Could be that an apprentice ruined the tool or did the work incorrectly. But, the responsibility has to fall back on the trainer.

I guess reputation means little to some folks. With so few new gunsmiths entering the field the remaining ones are having difficulties.

I also think the local village gunsmith has too wide a range of firearms to work on to make a real "Master" at any single type. Specialization may be the key here, but maybe the gunsmiths feel they'd be loosing paying customers when times are lean.

If I were to enter the professional field of gunsmithing at my age, I would certainly specialize. But them I would have my pension to fall back on in lean times.

 

[ColColt]

The reality is that Ruger was the one that cut it in the first photo-direct from the factory, brand new and my local gunsmith smoothed it out in the second picture. That pistol should have never left the factory like that.

 

[jrm53]

Thanks guys for the Good input, I will put 11 degrees in my note book before I forget it again, onced again no BS from the forum. Jeff

 

[Nemo288]

Had MagNaPort re-cut the forcing cone on my 1989 Mountain
Revolver. It looks like this:

Still not perfectly smooth but better than factory as regards
the tool marks. I have never seen a forcing cone perfectly smooth.
Guess I thought it was technically impossible. <j/k>

That link is some good dope. I may have to do some polishing.

---
Nemo

 

[WR Moore]

Factory barrels have their forcing cones cut with a specialized cutter. The first pictures seem to indicate a lack of lubrication during the cut, possibly also too high a feed rate.

Back when, the standard forcing cone was 18 degrees, then 11 degrees was used after the PPC guys popularized the concept. It also allowed the cleanup of some pretty bad 18 degree cones. Somewhere in between I measured some at about 14 degrees and ended up making my on tooling to recut them.