OT - Forcing cone ?

cshold · Post by **cshold** » Fri Jan 04, 2008 9:35 am

Question for you Knowledgeable revolver guys.

Why is 11 deg. considered the ideal bevel on a forcing cone?

salvo · Post by **salvo** » Fri Jan 04, 2008 10:11 am

The way I understand it, the target shooters determined that it was the optimal angle for lead bullets. Jacketed work well too.
I think the best thing about it is how nice it cleans up any imperfections the factory left.

J Miller · Post by **J Miller** » Fri Jan 04, 2008 10:33 am

I think the best thing about it is how nice it cleans up any imperfections the factory left.

Scott sure has this part right. I'm not sure exactly why the 11* forcing cone is so popular. I do know that it is a gentle angle to the bullets and when done right really does guide the bullets into the bore without deforming them.
Some of the more abrupt forcing cone angles aren't much better than no forcing cone at all.
I redid the forcing cone on my OM BH .45 last year and the difference was significant. Less leading was the most obvious improvement.
I can't say there is better accuracy yet, but the accuracy did not deteriorate. The groups are also a bit more consistent.

Joe

claybob86 · Post by **claybob86** » Fri Jan 04, 2008 11:17 am

If a forcing cone has circular tool marks left from the factory, would it be a good idea to polish those out by hand, or would that need to be done on a machine to preserve concentricity? I have one like that, but not sure if I should mess with it.

J Miller · Post by **J Miller** » Fri Jan 04, 2008 11:26 am

claybob86 wrote:If a forcing cone has circular tool marks left from the factory, would it be a good idea to polish those out by hand, or would that need to be done on a machine to preserve concentricity? I have one like that, but not sure if I should mess with it.

Brownells sells piloted brass laps to polish forcing cones. The only thing is you have to know what angle forcing cone you have so you don't use the wrong lap.

The piloted tool consists of a rod with pilots sized to the bore that center the rod. The rod has a T- handle on the outside end. The forcing cone cutter threads on the forcing cone end and you gently pull the rod and put a little pressure against the old forcing cone as you turn the cutter. The cutters are very sharp and cut through the steel fast.

Now, to polish or lap the forcing cone you use the same piloted rod but substitute a polishing lap for the cutter. It's easy to do really. I did mine even have some pics somewhere.

Joe

salvo · Post by **salvo** » Fri Jan 04, 2008 12:22 pm

Here is the tool that Joe is talking about.

And this is what the new 11 deg. forcing cone will look like.

As far as polishing your existing forcing cone, like Joe said, it is very important to have the same angled lap. From what I have read the last thing you want to create is a compound angle forcing cone.

BenT · Post by **BenT** » Fri Jan 04, 2008 12:59 pm

Is this an issue with all revolver calibers or just the 45 colt?

cshold · Post by **cshold** » Fri Jan 04, 2008 1:06 pm

Thanks much for the pictures.
I was always under the impression the barrel was removed to do
this. (not so with that tool)
Thanks, I learned something today

foxtrapper · Post by **foxtrapper** » Fri Jan 04, 2008 1:47 pm

Salvo where did you get the forcing cone tool? If its from Brownells do you have the order number?

salvo · Post by **salvo** » Fri Jan 04, 2008 2:46 pm

Brownells # 080-479-451
http://www.brownells.com/aspx/NS/store/ ... ING%20KITS

foxtrapper · Post by **foxtrapper** » Fri Jan 04, 2008 3:15 pm

That was quick

Thank you

DerekR · Post by **DerekR** » Fri Jan 04, 2008 4:54 pm

I appreciate those pictures Salvo. I have read a lot about that but never seen it in person. I can see where it might help with leading.
Is what you pictured the "Basic Chamfering Kit" and how hard is it to use for a shadetree gunsmith??

salvo · Post by **salvo** » Fri Jan 04, 2008 5:17 pm

Your welcome foxtrapper!

Yes it is the 11 deg. .38-.45 BASIC CHAMFERING KIT.
Very easy to use and like Joe said it cuts fast. Just go slow and as soon as the old forcing cone is gone, your done.

I wrote a Ruger Tune Up at the old forum, here is a copy of it over at Single-Actions.
http://single-actions.phpbb3now.com/vie ... ?f=8&t=307

J Miller · Post by **J Miller** » Fri Jan 04, 2008 8:19 pm

Derek,

When I did my forcing cone I put the barrel in a padded vise muzzle down and then pushed the tool rod up from the bottom.
I attached the cutter and gently let it down in the old forcing cone.
Then I made sure the pilot was in the muzzle and turned the handle. I barely put any pressure on the cutter. After each turn I inspected the cut and cleaned it off, then made another cut.
I forgot how many cuts I did, but I wanted to be careful to not cut too much.
I probably could have cut more, but I got a full cleaned up forcing cone and quit.

Joe

Nate Kiowa Jones · Post by **Nate Kiowa Jones** » Fri Jan 04, 2008 10:46 pm

The 11 degree cone is much easier on lead bullets for sure. Think of it like this. It's a funnel. Old style funnels had steep angles and if you poured into it too fast it sloshed over. The 11 degree cone is more like the long or tall sided funnels that allow you to pour faster with out sloshing over. When I do action work for CAS SAAâ€™s I always include the 11 degree cones.

A word of caution though, some of the CAS shooters load the really short 165 grain 45â€™s and even 90 grain 380 bullet for 38 specials trying to beat the recoil. Long 11 degree forcing cones cut too deep can actually cause the gun to shoot less accurate and lead even more. This is because the back of the bullet is not supported long enough to allow the front to stabilize into the barrel.

No one mentioned it but it's important to use a good cutting fluid when using this cutter. Makes for a much smoother cut, less leading.