Forcing cone results

[velocette]

As promised, had the duty of shooting the two revolvers that I re-cut their forcing cones.
I know, dirty duty but someone's gotta do it.
Accuracy with both revolvers seemed to be improved All shooting was done double action.
The 640 now made consistent hits on the 50 yard 20 X 24 silhouette and 40 % hits on a 12" plate also at 50 yards. The m15 also had consistent hits on the silhouette and about 65% on the 12" steel plate. That's better than I usually do.
Load was 158 LSWC from Missouri over 3.0 gr of Bullseye. So it appears that a moderate improvement of accuracy has resulted from the 11 degree forcing cone work. Money and time well spent.

 

[high country]

Good to hear. Any changes to the amount of leading you ended up with on either of those?

That is a pretty conservative load, not sure if you were getting leading before or not.

 

[velocette]

Good to hear. Any changes to the amount of leading you ended up with on either of those?

That is a pretty conservative load, not sure if you were getting leading before or not.

High Country; Both revolvers had about 40 rounds each run through them. Neither had any significant bore leading Cleaning patch came out with just a few tiny flakes & needed no brushing.. The
M 15 used to lead up a bit before but not much now.
Overall, the work was successful and kept me busy for an hour or so.

 

[Hooda Thunkit]

I've been meaning to get the tooling to cut the forcing cone on a few revolvers I have. Nice to see your results.

I need to move this up the priority list.

 

[high country]

High Country; Both revolvers had about 40 rounds each run through them. Neither had any significant bore leading Cleaning patch came out with just a few tiny flakes & needed no brushing.. The
M 15 used to lead up a bit before but not much now.
Overall, the work was successful and kept me busy for an hour or so.

Thanks for the update. I have a Model 15 that had tight throats, and leaded a bit. I cut the throats with a 4D reamer a couple weeks ago, but haven't had a chance to take it out since. Between that one and an SP101 that has a fairly rough cone, sounds like a cone cutter rental is likely worth the time/money. I probably should have just done both at the same time...

 

[AzShooter1]

I've cut the forcing cones on a few revolvers and always get a better gun from the deal. It's an easy job when you have the right tool. I got mine from Brownell's and have done a couple of .38s and my S&W 617 .22 that really needed it. Accuracy went way up.

 

[243winxb]

44 Magnum. Forcing cone mouth diameter- SAAMI doesnt seem to have a specification on it. Online a guy said groove diameter X 1.05" = diameter.
My S&W 44 mag would have a forcing cone mouth diameter of .450" using this math.

The photo shows .451" diameter bullet in the barrel. Not even close to a tight fit.

The flat base bullet has stopped in the barrel where it measures .451" Seems like a lot of slop?

The factory set the barrel back last year. & cleaned up the forcing cone.

Does anyone have specifications of what it should measure?

 

[243winxb]

A .430" flat base bullet goes in about .258" deep with a factory forcing cone.
A .451" flat base bullet goes in about .100"

A 11 degree may go .265" from barrel face to the .430" barrel diameter?

Would seem my forcing cone is ok.

Using very crude measurements & eyeballing it.

 

[243winxb]

Some good photos of a 45 acp revolver barrel being done .https://www.bullseyeforum.net/t5517-revolvers-barrels-forcing-cones

Takes the whole bullet? Seems odd? View attachment 974749

 

[UncleEd]

Velocette,

So you had a good day shooting. See if you
duplicate performance another day, or two.

Then you will have more solid confirmation
your work has paid off.

 

[high country]

Velocette,

So you had a good day shooting. See if you
duplicate performance another day, or two.

Then you will have more solid confirmation
your work has paid off.

It can definitely be hard to sort out small improvements in handgun accuracy vs. good and bad days. But, if he reduced the leading from cast loads, that alone would be worth the effort and cost to me. I prefer to minimize my time with a chore boy and bore solvent where I can...

 

[243winxb]

The Taylot Throat is the photo in post #9. http://web.archive.org/web/20020606140647/www.sixgunner.com/dad/throat.htm

"Throat" is misleading, because its just past the forcing cone in the barrel. View attachment 975166

 

[Jackrabbit1957]

I play with cap and ball revolvers quite a bit, cut all of my open top Colt replicas with an 11 degree cutter. Results were very good, especially on my Walker, which only had a slight bevel where the forcing cone should have been. Bought my tool from Brownells, best money I've spent in a long time.