GP100 - Forcing Cone

donkbet

donkbet

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Hey guys, I have a question regarding my new GP100. I posted on another forum the other day regarding some potential rust that was on the revolver. Pretty sure it's just dried up preservative oil though. I also posted a shot of the forcing cone and asked if it looked okay. This is my first revolver so I don't know much about things like forcing cones. I wasn't expecting the answers I got; things like "... looks like it was found in a parking lot" and "worst forcing cone I've ever seen." They said that there seems to be no angle to it. Also that the inside is "full of machining rings." I emailed Wanstalls about the situation and received a great reply. Daniel said that to him, it looks normal and shouldn't be a problem, etc. He did say I can exchange it for a new one though.

Do you guys think I should exchange it? Or does the forcing cone look normal? Thanks!


 
It's fine, don't worry about it and shoot the gun. The lines inside the cone are from the cutting tool that cuts the angle, some look worst than other but it doesn't affect the gun's shootability.

P.Barrette
Snap Shots inc.
 
Hard to tell from the photos, but it looks cozmetic to me. If you have a feeler gauge check the gap for uniformity and overall close fitting. It should be .004 to .008 inches from the cylinder IIRC. Also check fron different angles to ensure the gap is even. If it is, then I'd say keep it.

To me the toolong marks on the cone and the inside of the frame talk about cutting corners to meet Rugers insane demand. Getting a new one wont necessarily help you. They will all have tooling and chatter marks.
 
Thanks for the quick replies. It's good to hear that it looks normal. I asked on yet another forum and got some responses, saying it looks to be normal. I was surprised when I asked on thehighroad about it and basically everyone said it looked like s**t and I should return it. I have a couple of questions. This is my first revolver so I don't know a lot about the technical details. What does the angle look like? Is it on the inside of the forcing cone? Should it be noticeably visible? Looking at it, I don't see any sort of angle anywhere. My other question is about the "machining rings." Do they look okay in these pics? I was told that these could lead to significant lead build up and be a real pain in the ***, and even dangerous.

curseyou said:
Hard to tell from the photos, but it looks cozmetic to me. If you have a feeler gauge check the gap for uniformity and overall close fitting. It should be .004 to .008 inches from the cylinder IIRC. Also check fron different angles to ensure the gap is even. If it is, then I'd say keep it.

To me the toolong marks on the cone and the inside of the frame talk about cutting corners to meet Rugers insane demand. Getting a new one wont necessarily help you. They will all have tooling and chatter marks.
Click to expand...

Unfortunately I don't have a feeler gauge to check it :(
 
As for machining rings being dangerous. Absolutely not. Not any more dangerous than a museum grade revolver of the same make and model.

As for the angle thing, I did not explain myself clearly enough. When the cylinder is closed, hold the pistol to a light and look carefully where the cylinder meets the forcing cone. There is a gap between the two. The gap is more important than the cosmetic appeal of the forcing cone. Go to princess auto, canadian tire or some place similar and get a set of gap gauges, aka feeler gauges. This is a multitool with lots of flat metal tomgues of very precise thickness. You can slide these into the very small gap to measure how big the gap is. As I said I recall the gap needing to be .004 to .008 inches. Too small and the cylinder risks locking up when dirty. Too large and you lose power and will have a larger flame coming out the side and possibly some splatter from lead.

I suggest not only do you stick the feeler gauges to find out the gap, but that you stick the feeler gauges into the gap coming from different angles. Looking down the barrel, you can stick in the feeler gauge from the left and right sides (3 and 9 oclock) My reference to angles was about poking the gap from all the different Oclock approaches in order to gauge the uniformity of the gap. It is hard to tell from the photos but there may be a larger gap at 2 oclock. If there is I would consider returning it. If the gap is in tolerance and uniform all around, then she is a keeper.
 
Also a larger gap is not spec. That doeant mean it is bad or unsafe. Many competition guns get their forcing cones opened up by smiths to .008 and even .010. I have one such postol that was worked by a smith for such purposes. The smith who owned it wanted to a little more edge off his 38spl rounds.

Personally I would have just loaded lighter rounds, but thàt didnt stop me from buying the gun off the guy when he stopped shooting.
 
When you take great looking macro pictures like this just about anything looks rough and poorly finished.

The forcing cone taper is a very slight angle. So it's no wonder you don't see the angle. The spot shown in the second pictures IS the cone. The reamed area extends about 1/4 inch into the bore and it's roughly a 10 to 11° taper. If you get into the frame with a mirror so you can look deeper into the bore you'll see how the cone transitions to the rifling.

When you close the gun and look through the gap it should be a thin sliver of light. You most certainly do not want the metal to touch. And if you make up a slip of printer paper that is a little wider than the back end of the barrel stub it should pull through easily. If you use two layers it might or might not pull through. Printer paper is typically .003". So a double fold is .006 to .007 just because the surface texture might hold it apart a touch. And obviously a triple fold should simply not fit since that suggests something up around .010" So that gives you a quick and easy "Go" and "No Go" test option.

WIth this paper test you want to slip the paper in place as you close the cylinder into the frame since it lacks the stiffness to poke it in.

You want SOME gap so that powder fouling does not cause cylinder drag. But too much gap and you start to lose some muzzle velocity.

If the surface finish on the cone does begin to lead up a smith can run a forcing cone reamer into it to clean it up somewhat. One gun of mine in particular was pretty rough. I had Rusty Wood Trading in Mission do the work and it was something like $40 to $50 as I recall. As it happens this didn't help anything at all other than I felt better.... :D
 
Great replies guys, appreciate them very much! I bought a set of feeler gauges. The .004" just fits the gap (a little tight though.)

I fully agree with you BCRider about the macro shots. Looking at it in person, it doesn't look as bad. The machining rings aren't as noticeable either. I think the direct sunlight really brought them out in the second pic. I'm beginning to think that the revolver is A-OK and I'll keep it. Just got a bit of a scare when the guys on the other forum said it looked so bad.

Cheers
 
donkbet said:
......I fully agree with you BCRider about the macro shots........
Click to expand...

Some things are better not seen in close up. You and your cutting marks on the forcing cone and me when I saw a tight in shot of Robert Downey Jr's face in Ironman on my then new 60 inch plasma HD TV. I darn near jumped out of the couch at seeing the "moonscape" skin! ! ! ! :D
 
I polished the forcing cone of my GP100 to near mirror to reduce lead fouling.
But then again, I shoot lots of lead through it.
Your cone is fine.
 
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