Bubba Takes on His Forcing Cone, . . .

[Jeff R]

The finish of the forcing cone on my SBH is the stuff of internet legend.

http://castboolits.gunloads.com/show...-Forcing-Cones.

I got a couple tools from Brownells and had at it. Here's the before and after pics:

Before


After


here's the stuff from Brownells


I could have taken more off, but I can always go back and re-treat. I'll see how it shoots, and if it leads in front of the barrel thread area. All I need is minute-of-trifocal accuracy.
Thanks for looking.
Jeff

Rocketing towards 200 posts!

[Fatdaddy]

Looks like a big improvement.
Any idea what Bubba used to dress it before you got it or what he was trying to accomplish?

[Jeff R]

Fatdaddy,
That 'Before' photo is how it left the factory. I bought the revolver new in 1984.
Jeff

[DougGuy]

Where is the cutter? You should have an 11° cutter to use before the lap. The lap won't hold it's shape long enough to fully dress a bad cone, it gets ridges worn into it in a heartbeat then it don't cut straight. I found what works the best is to use the 11° cutter with Tap Magic, only cut a little at a time and clean it up and look at it, then when I am finished with the cutter I take a little piece of 000 fine scotchbrite and poke a hole through it, thread it on to the rod and screw the brass lap on, push the scotchbrite into the bore with the lap backing it and give it a few twists. It smoothes up the job a LOT better than that brass lap does.

This is what one looks like just after the 11° cutter finishes, this is without any lapping or polishing:

[IllinoisCoyoteHunter]

I need to do this to my GP100. Any idea where to get the cutter and other necessary tools to accomplish this? Maybe the OP can post a few links. The pic is hard to see but it looks like it is much better than when it left the factory.

[Jeff R]

DougGuy,
As an entry level Bubba, I was not aware that a cutter should preceed the brass lapping cone. Now, I see that I'll have to get a 11 degree cutter to complete the job. At any rate though, I believe that the forcing cone is greatly improved, and no harm has been done.

The brass lapping cone did start to develop rings around it. If I need to use it again, I can smooth it. Thanks for your help. I have a cylinder from another pistol that I'll be sending to you.
Regards,
Jeff

[hpdrifter]

4D rental.

[Jeff R]

I need to do this to my GP100. Any idea where to get the cutter and other necessary tools to accomplish this? Maybe the OP can post a few links.

I.C.Hunter,
I got the stuff from Brownells. I retro-hindsight, I did not need the deburring tool, but I'll keep it for the big garage sale someday. My wife should be able to get a buck for it. Here are the Brownells part numbers. All the stuff was in stock, and I had it two days later.



I'll have to check into renting a cutter. If I buy one, I may have other chances to use it before the Big Sale.
Regards,
Jeff

edited -
the part number for the cutter is:

080-486-200WB (In Stock)
Fits .38-.45 Caliber


Rocketing towards 200 posts!!

[DougGuy]

I need to do this to my GP100. Any idea where to get the cutter and other necessary tools to accomplish this? Maybe the OP can post a few links. The pic is hard to see but it looks like it is much better than when it left the factory.

Your GP100 likely has a 5° forcing cone. If it isn't cut really far into the bore you can use an 11° cutter on it, but if it's long already it won't do any good because the boolit will never touch the 11° part, this will only work if Ruger didn't cut it very far. 4D rents the tool, and there is a video that shows them using the tool, but unless you have done a few of these it's hard to know what you are looking at when you start, and it is VERY EASY to overdo.

I do forcing cones but it has to go to my local FFL which the whole job will cost a bit more than the tool rental but you get fast and accurate work done without the liability of messing it up if you are not quite sure what needs to be done.

[DougGuy]

DougGuy,
As an entry level Bubba, I was not aware that a cutter should preceed the brass lapping cone. Now, I see that I'll have to get a 11 degree cutter to complete the job.

You should get the pilot bushing before you do any more work on the cone. This is a brass bushing that slides down into the bore and rests just ahead of the cutter, it keeps the rod that attaches to the cutter concentric with the bore. Many forcing cones are not cut concentric with the bore, this causes major problems and cannot be corrected without a piloted cutter. Any other means of smoothing or changing the forcing cone angle or polishing the cone relies on the cone itself to guide the tooling and if the cone is not perfectly concentric with the bore, it will throw off all of your smoothing and polishing efforts and can make the issues even worse as far as shaving boolits as they enter the bore and spitting lead out the barrel cylinder gap.

[Jeff R]

DougGuy,
Thank You even more. I orderd the cutter, but was not aware for the need for a guide bushing. I believe I can make one out of materials I have on hand. The journey continues!
Regards,
Jeff

[bluelund79]

Going to be following this one. Looks great so far, just something I don't have the stones to do myself

[freebullet]

Ruger ss is some hard stuff.

[390ish]

I had the same problem, but S&W re barreled free of charge.

[DougGuy]

And now that the wheels are a turning, let me further opine on a subject that you may have right in front of your nose, and just yet to find out about it, thread choke. You mentioned leading after the first inch of bore, which would be a hint that the bore gets slightly larger after it clears the threaded portion that threads into the frame. You can check this with a pin gage, OR the poor man's way with a tightly patched cleaning jag pushed down the bore. IF it gets tighter when it gets to the threaded part, this is thread constriction, brought on by Ruger when they torqued the barrel to the frame in "clocking" the front sight up to 12:00 noon. If it gets REALLY tight, the choke is severe, likely .002" to .003" which brings up yet another problem which is very common to the .45 caliber revolvers, less common to the .44 caliber, as their barrel walls are thicker and less affected by this torquing action.

If you have a thread choke, the pilot you fit into the muzzle to ride on the lands will go down the bore until it gets to the choke, and it will stop. When it stops, it may stop short of going right down to the cutter bit, and you have to either make a smaller pilot, or go very slow and easy so the cutter doesn't get deflected and cut off center, if the existing cone is not perfectly centered in the bore. If it is concentric, then it will all work out for the better, but like I said, a lot of them aren't concentric, and it is your aim in this endeavor to correct the issues with it, concentricity being the most important part.

Depending on how many rounds have been put downrange, and how well the cylinder throats index to the bore when in lockup, the forcing cone can become eccentric just from normal wear of shooting thousands of rounds. If several of the throats tend to index to one side, this side will show more wear and this is what you want to correct when you recut a forcing cone.

OTOH, a revolver that shoots really well, that has worn it's own pattern in the forcing cone, that doesn't spit or lead the bore excessively would be better off left as is, or with minimal polishing of the existing cone, since it will just start this wear pattern all over again and accuracy may indeed suffer because of this. This is a problem that left the factory with a cylinder that didn't index well, but has been "shot in" to the point that it has indexed itself and should probably be left as is when it comes to the forcing cone. The forcing cone in a revolver like this would look a bit odd when you cleaned it up and got a bright light and a mirror where you could see it really well, it would look to the mechanical eye like something is not right about it. THIS is where you LISTEN to what the gun is TELLING YOU, instead of what your EYE thinks things should LOOK LIKE.

Ruger stainless is 400 series alloy, it is TOUGH STUFF. It is not that difficult to machine, but it is a BOOGER BEAR to firelap. You could likely lap a choke of .001" to .0015" using normal firelapping techniques, but if you have one that is .003" by the time you firelap that much out, the rifling in the remaining good part of the bore is very likely to become damaged to an unpredictable degree. These need to go back to Ruger, OR have the choke removed by Taylor throating. Blued carbon steel is much easier to firelap, and smoothes up nicely in roughly 1/3 the amount of work as stainless.

[Fatdaddy]

Fatdaddy,
That 'Before' photo is how it left the factory. I bought the revolver new in 1984.
Jeff

Wow, I thought a "Shadetree" had tried to dress it. Didn't realize you were referring to yourself as Bubba.
In this case "Bubba" did alright.

It's amazing what makes it past QC sometimes.
Check out this BBL from S&W:

[tazman]

And now that the wheels are a turning, let me further opine on a subject that you may have right in front of your nose, and just yet to find out about it, thread choke. You mentioned leading after the first inch of bore, which would be a hint that the bore gets slightly larger after it clears the threaded portion that threads into the frame. You can check this with a pin gage, OR the poor man's way with a tightly patched cleaning jag pushed down the bore. IF it gets tighter when it gets to the threaded part, this is thread constriction, brought on by Ruger when they torqued the barrel to the frame in "clocking" the front sight up to 12:00 noon. If it gets REALLY tight, the choke is severe, likely .002" to .003" which brings up yet another problem which is very common to the .45 caliber revolvers, less common to the .44 caliber, as their barrel walls are thicker and less affected by this torquing action.

If you have a thread choke, the pilot you fit into the muzzle to ride on the lands will go down the bore until it gets to the choke, and it will stop. When it stops, it may stop short of going right down to the cutter bit, and you have to either make a smaller pilot, or go very slow and easy so the cutter doesn't get deflected and cut off center, if the existing cone is not perfectly centered in the bore. If it is concentric, then it will all work out for the better, but like I said, a lot of them aren't concentric, and it is your aim in this endeavor to correct the issues with it, concentricity being the most important part.

Depending on how many rounds have been put downrange, and how well the cylinder throats index to the bore when in lockup, the forcing cone can become eccentric just from normal wear of shooting thousands of rounds. If several of the throats tend to index to one side, this side will show more wear and this is what you want to correct when you recut a forcing cone.

OTOH, a revolver that shoots really well, that has worn it's own pattern in the forcing cone, that doesn't spit or lead the bore excessively would be better off left as is, or with minimal polishing of the existing cone, since it will just start this wear pattern all over again and accuracy may indeed suffer because of this. This is a problem that left the factory with a cylinder that didn't index well, but has been "shot in" to the point that it has indexed itself and should probably be left as is when it comes to the forcing cone. The forcing cone in a revolver like this would look a bit odd when you cleaned it up and got a bright light and a mirror where you could see it really well, it would look to the mechanical eye like something is not right about it. THIS is where you LISTEN to what the gun is TELLING YOU, instead of what your EYE thinks things should LOOK LIKE.

Ruger stainless is 400 series alloy, it is TOUGH STUFF. It is not that difficult to machine, but it is a BOOGER BEAR to firelap. You could likely lap a choke of .001" to .0015" using normal firelapping techniques, but if you have one that is .003" by the time you firelap that much out, the rifling in the remaining good part of the bore is very likely to become damaged to an unpredictable degree. These need to go back to Ruger, OR have the choke removed by Taylor throating. Blued carbon steel is much easier to firelap, and smoothes up nicely in roughly 1/3 the amount of work as stainless.

Thanks for posting. That is excellent information.

[Jeff R]

DougGuy,
Please keep this information coming! I have done the tight patch test, and if there is some thread choke, in my novice Bubba opinion, it is not too severe, going by the feel of the cleaning rod as the patch hits that area. It could be a problem though, but I figured why bother with that until I got the cheese grater forcing cone taken care of.

Then, I'll have to verify that the cylinder throats are big enough. There is one out of the six that is slightly tighter. After I finish the forcing cone, I'll shoot a bunch, but I'll leave the chamber with the smaller throat empty and see if it makes any difference. Then, I'll shoot some, only using the suspect chamber, and see if that makes any difference.

I just want to jump off one bridge at a time. Lastly, I'd look at fire lapping. I have ordered the technical guide from Beartooth Bullets. My buddy had to firelap a stainless revolver and has the Beartooth kit. He did mention that it took "A Lot" of bullets. I'd just have to get some lapping bullets. My 11 degree cutter should be here in a couple days. I'll update you after I use that. Also, I won't use it without a pilot bushing.
I owe you even MORE now!
Regards,
Jeff

aka: novice Bubba

Rocketing towards 200 posts!!

[bhn22]

Attachment 129942

My kits only set up for 11 degree forcing cones so far. You will also need the plug gauges to match your selected forcing cone angle to prevent you from cutting the forcing cone too deep. You can't just keep cutting until you clean up the old forcing cone. Likewise, not all forcing cone angles will clean up with just any reamer. Unless you get everything right, you risk cutting a forcing cone with two different angles, and that does not help you achieve your goals at all.

[Jeff R]

Attachment 129942

My kits only set up for 11 degree forcing cones so far. You will also need the plug gauges to match your selected forcing cone angle to prevent you from cutting the forcing cone too deep. You can't just keep cutting until you clean up the old forcing cone. Likewise, not all forcing cone angles will clean up with just any reamer. Unless you get everything right, you risk cutting a forcing cone with two different angles, and that does not help you achieve your goals at all.

More Great info. The journey continues!
Regards,
Jeff