Should I 11 degree cut my forcing cone or polish it?

[Stopsign32v]

My GP100 is among my favorite revolvers and it has pretty much perfect chambers at .357.

Would it benefit for me to cut the forcing cone to 11 degrees? Also does polishing the forcing cone help? I saw a guy polish his forcing cone with valve lapping compound.

[centershot]

If it shoots good the way it s, don't mess with it!

[gwpercle]

If it ain't broke ... Fix It !

Actually ... I would get advice from DougGuy ... he knows way more about forcing cones than I do ... I can advise you on Ice Cream Cones ... I have years of experience with those !
Gary

[Outpost75]

11-degrees won't clean forcing cone angle of GP100. You will wreck it!

[Stopsign32v]

11-degrees won't clean forcing cone angle of GP100. You will wreck it!

What do you mean?

I've only ever shot fmj or plated in this revolver. But I would like it to be a lead shooter mainly.

[Outpost75]

What do you mean?

I've only ever shot fmj or plated in this revolver. But I would like it to be a lead shooter mainly.

GP100 forcing cone is shallower angle than 11 degrees so the 11-degree reamer will enlarge the forcing cone opening and not clean up tool marks.

[Winger Ed.]

I tend to go real easy on modifications like that.
I figure the folks that designed and built it know a lot more about what & why they did something than I ever will.

[JimB..]

Doesn’t Ruger cut theirs at something close to 5 degrees, and very shallow? Looks like a slight chamfer rather than a cone. I can’t see how changing it to 11 degrees would wreck it, and it would cut away all of the current 5 degree cone.

But that’s just my thought, ask dougguy.

Gwpercle, waffle cones are much better than sugar cones!

[schutzen-jager]

11 degree + polishing showed no improvement under controlled test conditions on the only one i tried, S&W 10-4 -

[country gent]

I would test it first with cast bullets before modifying it. My security six performs well with cast and jacketed both as it came from factory.

[Stopsign32v]

I would test it first with cast bullets before modifying it. My security six performs well with cast and jacketed both as it came from factory.

How do you tell if it needs to be adjusted? Bad accuracy and leading or what?

[Outpost75]

How do you tell if it needs to be adjusted? Bad accuracy and leading or what?

Visual inspection. Circumferential tool marks. Leading.

[DougGuy]

11 degrees will only address the first bit of the existing cone, and you got this longer section of 5 degree cone in front of that 11 degree part. If you rent a forcing cone cuter kit, they typically have a 5 degree cutter and also a 5 degree brass lap, along with the 11 degree cutter and lap

Get the barrel really clean, poke the 5 degree lap into the existing FC, and see if you can wiggle back and forth. If so, that means your existing FC A.) may not be cut on 5 degrees, or B.) the barrel isn't clean of all fouling and lead.

If the 5 degree lap goes into the barrel until it stops, and the loose part is near the entrance to the barrel, FC angle is greater than 5 degrees. If it bottoms out at where the forcing cone would be and the end in the barrel is not tight, that means the part right there at the entrance to the barrel is the tight spot. Use the lap and observe how it moves before you decide on cutting.

[Stopsign32v]

I don't know if this tells you guys much or not. But if so...Opinions?

[DougGuy]

I don't know if this tells you guys much or not. But if so...Opinions?

That's a shallow angle like 5 degrees. You need the cutter that matches that degree to do any cleanup. 11 degrees will only widen the part at the fire ring it won't clean up any of those tool marks past what the 11 degree cutter reaches in and cuts. You would be weakening the barrel for one, and removing metal where it doesn't need to be removed. You cannot "fix" a 5 degree forcing cone with an 11 degree cutter.

[Stopsign32v]

Doug,

What about some valve lapping compound for a few turns to get rid of the tooling marks? Follow up with some metal polishing compound.

[Outpost75]

Lapping compound will knock off some of the high spots, but not remove the tool marks.

[DougGuy]

Doug,

What about some valve lapping compound for a few turns to get rid of the tooling marks? Follow up with some metal polishing compound.

You could/should call Ruger and show them those photos see if they will take it in and fix it. It's a QC issue they may or may not address but if they are going to do it, DON'T do anything on your own just sweet talk them into handling it.

PS. Don't tell them it leads, don't tell them you handload you get the picture? Tell them it groups terribly.

Doug

[Stopsign32v]

You could/should call Ruger and show them those photos see if they will take it in and fix it. It's a QC issue they may or may not address but if they are going to do it, DON'T do anything on your own just sweet talk them into handling it.

PS. Don't tell them it leads, don't tell them you handload you get the picture? Tell them it groups terribly.

Doug

Do you see anything that is wrong with it? What would Ruger "fix"?

I know what is coming...But there is nothing that I know of that is wrong with it. I was just wanting to make it better if it would.

[JimB..]

Do you see anything that is wrong with it? What would Ruger "fix"?

I know what is coming...But there is nothing that I know of that is wrong with it. I was just wanting to make it better if it would.

You need to decide what “better” means for you. I have a couple S&Ws that look worse than that but shoot fine, so I don’t bother trying to “fix” them. Nothing wrong with saying that it just bugs you that they aren’t cleanly cut, but if they shoot well do you really want to risk making a change?