Chamfer forcing cone on an old stainless Ruger

[RedHawk357Mag]

Looking for some insight to a problem I am having. Fire lapped restrictions out of my Redhawk and also decided to chamfer the forcing cone to 11 degrees. My first Redhawk a 44 Magnum cut just fine and shoots much better. My 357 Magnum has been quite a challenge. With my first attempt with the 357 I got just short of a 1/8" cut in the cone. That was after about 2 hours of turning the chamfering cutter. No chips of metal. I am getting what appears like the fine grit you would get while sharpening a knife on a fine grade whetstone. Called Brownell's tech support and asked what was expected life of a cutter. He said his is going on 20 years. I ordered a new cutter and it arrived today. Exactly the same thing. The cutter has a drag mark of where it has rubbed the mouth of the forcing cone so long. Have tried different amounts of force while pulling the True handle. Tried Triflow superior lubricant and WD40. Both cutters are M. A. Ford 38_45 Cal 11 degree chamfer tool number is 800003250005. I have only turned in the direction of cutting only. Have made a very concentrated effort to ensure I haven't done anything funky with the second cutter. Got about a 1/4" to the minus side of 3/8" of cut metal. I also have a small lip on forcing cone mouth that now drags the cylinder. Any thoughts? Thanks.

[RedHawk357Mag]

Also using the brass bushing in the barrel and aluminum centering muzzle guide as well.

[Silverboolit]

Is it possible that the barrel has 'work hardened' over the years?

[knifemaker]

I have to agree with the idea your older stainless revolver had the forcing cone "work harden" due to numerous firings. To harden stainless steel you heat it up and allow it to air cool to harden it. Your hot gases on firing the gun has done that on the surface and a few thousands deep on the forcing cone.
It is now very close in hardness to your forcing cone cutter and it is like using a metal file trying to file metal off another metal file in layman terms. Also you should be using a fluid made for cutting or tapping threads in steel, not a lubicant like WD40.

[RedHawk357Mag]

Interesting. Does make sense. Problem is I am currently a 1/4" from the lands so I got the dreaded compound angle going on in the forcing cone. From what I have read I need to get the 82 degree chamfer to break the raised edge on the face of the cone. Thanks for giving me a possible why it's being a pain in the butt.

[WALLNUTT]

WD40 is not really a lubricant. It is for Water Displacement.

[detox]

I had the same problem with Brownells 5 degree cutter for 44-45 caliber revolver. I returned cutter twice for exchange, but same problem. I ended up cutting it to 10 degrees, but oversize with better cutter. Midway sells these.

My 5 degree, 38 caliber M A Ford brand cutter cut my Stainless 686 very easily using cutting fluid. I do not know if WD40 will work or not.

Sounds like you have a bad cutter or cutters. Get refund.

[RedHawk357Mag]

I used the Trifoil lube on the 44 which cut as I expected it to. The 44 is probably several years junior to the 357 which would make the case for case harding. Tryed the WD and Kroil before it was over with. Will order some recommended cutting fluid form what ever Brownells is pushing. I also expect the 44 probably didn't get shot a whole bunch unless it was jacketed ammo as it leaded like no other and was quite disappointing in accuracy before firelapping and chamfering. Although some of the case harding was probably eroded by the fire lapping. I looked for a different brand of cutter on Midway but I didn't see a 11 degree. I sure would like to try a different brand than the MA Ford. They may make a quality product but I just can't tell from my limited experience. Again thanks for sharing thoughts on this. Very appreciated.

[John Boy]

... also decided to chamfer the forcing cone to 11 degrees.Waste of time. Ream the throats on the cylinder for better performance. Uniform throats align the bullets to the cone which is the importance for better accuracy

[RedHawk357Mag]

Throats were done about four years ago by Cylinder Smith. He Uniformed them to. 359" which I confirmed with Vermont pin gauges. It did help a lot but still spit a bit of lead, lead build up on forcing cone and where barrel screws into the frame. The results of the 44 from forcing cone chamfer say otherwise. The 44 always leaded fiercely with varying degrees of lead hardness and bullet sizes and profiles. Powder from RedDot to 296 and everything in between minus any AA or VihtaVuori powders. Until the fire lapping and chamfer that pistol had never put six rounds in a paper plate off bags at 25 yards. This may be one of those YMMV situations. As I consider the Ruger 44 a success. Appreciate the response as I am certain a solution exists just got to barn storm it.

[44man]

You MUST use real cutting oil, not lubes. Never had a problem cutting cones, peels out steel so easy I have to keep measuring. I had to make several barrel bushings over the years to fit barrels not the exact size. They must be snug so there is no chatter.

[detox]

Pacific Tool and Die can make you a good cutter at a reasonable price. Talk to Jessica

[detox]

You can buy cutting fluid at Hardware store. I used Tap Magic brand

[RedHawk357Mag]

All good info folks. I sent the two cutters back to Brownell and ordered one to be replaced and a 90 degree cutter for breaking the lip on the forcing cone. I also bought some Viper Venom cutting oil. Detox thanks for the heads up on Pacific tool. I will surely check them out should this next Brownell cutter burn in. Will post the results of the replacement cutter and whether I need to get a cutter made. All information is greatly appreciated.