Forcing cone angle

1100 tac · May 24, 2015, 07:42 PM

Does anyone know the forcing cone angle on a M29 from 1994??

GP100man · May 24, 2015, 08:22 PM

Contact Doug Guy over on Castboolits , he`s the best I`ve seen on throats & cones on revolvers . He`s worked magic on 5 of mine !!

GP

1100 tac · May 24, 2015, 08:45 PM

Good idea.

Clark · May 24, 2015, 08:54 PM

I have a 1907 vintage colt 32 S&W Long that blew out the forcing cone with wimp loads. So I welded it up and cut a new one at 11 degrees and thicker. I got 1413 fps over the chrono with an 85 gr bullet.

1100 tac · May 24, 2015, 10:59 PM

That's great Mr. Clark, but what is the factory angle of a M29...

Clark · May 24, 2015, 11:40 PM

My 29-4 was made in 1988 and using it and axxent clay fun and a protractor, it looks like 11 degrees.

Since i took that pic, I learned to tape the protractor to the graph paper.

1100 tac · May 25, 2015, 06:21 AM

Thank you.

**Unclenick** · May 25, 2015, 04:41 PM

1100 Tac,

11° is a pretty standard forcing cone angle. ONe new revolver I bought that had something different was my Dan Wesson 15-2, which came with 5° throat angles on the two barrels I have for it. The S&W's I have are all 11° if they are factory.

Changing to 5° used to be a standard revolver smith's accurizing technique for shooting lead bullets. I believe, however, that cutting of the shallower angle was often done with a piloted pull-through reamer and the final forcing cone cleaned up with laps, in situ. That would allow the longer taper to get at least into if not past the barrel constrictions commonly found in that part of the gun, which might well have been the main source of the beneficial effect.

jepp2 · May 25, 2015, 05:22 PM

My experience seems to be different. My understanding is that S&W uses an 8 degree cutter to cut the forcing cone. Kind of a compromise between what works best for jacketed (5 degrees) and cast lead (11 degrees).

I have recut a few S&W's I use mostly for lead. I use an 11 degree cutter and it has certainly changed the angle that it came from the factory with.

If you recast your barrel using Cerrosafe you will get a much more accurate mold to measure the angle with.

1100 tac · May 26, 2015, 06:57 AM

Re: cerrosafe

I have cerrosafe and know how to use it, the problem is pouring just the right amount in order to get the cast out, and have enough length to accurately measure the angle, plus if there is a bore restriction at the bbl threads it would have to be pounded out, I don't want to do that...

The goal here is to make a lap to polish up what I have a little. I can make different angled laps until I match it, but I wanted to save time and materiel.
I never dreamed that it would be this hard to find out the spec.

I have posted this on four forums and the #'s have come back all over the place, "I think" and "probably" , So, I don't think anyone out there in internet land really KNOWS...

Will be calling S&W today to see if THEY know...

Thanks for the responses guys, I will let you know what Smith says.

F. Guffey · May 26, 2015, 08:34 AM

Quote:

I have posted this on four forums and the #'s have come back all over the place, "I think" and "probably" , So, I don't think anyone out there in internet land really KNOWS...

http://www.saami.org/PubResources/CC...n%20Magnum.pdf

F. Guffey

F. Guffey · May 26, 2015, 09:03 AM

Quote:

I will let you know what Smith says.

Why? I am not even curious.

F. Guffey

**Unclenick** · May 26, 2015, 09:41 AM

Jepp2,

It may be the age of my Smiths. Nothing recent. It can fool you, though. I have had the experience with a .357 Magnum barrel (one of my DW's) of chucking it in the lathe and finding a dial indicator showing a 3° angle over the center to rifling portion of the forcing cone. That, however, was created by erosion. The newer barrel's less worn forcing cone is flatter and 5°.

If Cerrosafe isn't convenient, you can always apply mold release and put some quick set epoxy putty in for an impression. Exact dimensions don't matter, as the angle will be the same even if the diameters overall all are a tiny bit smaller.

mikld · May 26, 2015, 11:09 AM

http://www.saami.org/PubResources/CC...n%20Magnum.pdf Doesn't show forcing cone angle. The eleven degree, six minute dimension is for the chamber. Note to the right side of the drawing the noted "Barrel Face" and "Cylinder Face", but no angle called out...

F. Guffey · May 26, 2015, 12:37 PM

Quote:

I have posted this on four forums and the #'s have come back all over the place, "I think" and "probably" , So, I don't think anyone out there in internet land really KNOWS...

You have covered the Internet reloading forums like the wind and found:

Quote:

don't think anyone out there in internet land really KNOWS

Quote:

Why? I am not even curious.

But if I was and I wanted to know I would seat a bullet into a case without powder, I would then chamber the round and pull the trigger. If I was curious about the most powerful primers I would use different primers to determine how far each drove the bullet in the forcing cone.

F. Guffey

1100 tac · May 26, 2015, 12:45 PM

Mikld:
I noticed that, more non-info from FGufy.

FGuffy: If you are not curious, I won't twist your arm to read anything I post

.

Going to see what S&W says when I get home.

F. Guffey · May 26, 2015, 12:56 PM

Quote:

FGuffy: If you are not curious, I won't twist your arm to read anything I post

Quote:

don't think anyone out there in internet land really KNOWS

Again, seat seat a bullet into a primed case without powder, chamber the round and pull the trigger. Use a jacketed bullet or a lead bullet. And then drive the bullet back into the cylinder. Check the impring on the bullet.

Or as you say:

Quote:

I have cerrosafe and know how to use it, the problem is pouring just the right amount in order to get the cast out, and have enough length to accurately measure the angle, plus if there is a bore restriction at the bbl threads it would have to be pounded out, I don't want to do that

You know how to use cerrosafe.

F. Guffey

F. Guffey · May 26, 2015, 03:50 PM

I have 3 S&W barrels, two are magnum types. Both have bulges, one has 6 jacketed bullets stacked one behind the other. It was not a matter of removing the bullets, the forcing cone had expanded .011".

There were a number of 11 degree responses, and I wondered.

F. Guffey

May 24, 2015, 07:42 PM	#1
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Forcing cone angle Does anyone know the forcing cone angle on a M29 from 1994??

May 24, 2015, 08:22 PM	#2
GP100man Senior Member Join Date: August 1, 2007 Location: Tabor City , NC. Posts: 1,969	Contact Doug Guy over on Castboolits , he`s the best I`ve seen on throats & cones on revolvers . He`s worked magic on 5 of mine !! GP __________________ GP100man

May 25, 2015, 04:41 PM	#8
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	1100 Tac, 11° is a pretty standard forcing cone angle. ONe new revolver I bought that had something different was my Dan Wesson 15-2, which came with 5° throat angles on the two barrels I have for it. The S&W's I have are all 11° if they are factory. Changing to 5° used to be a standard revolver smith's accurizing technique for shooting lead bullets. I believe, however, that cutting of the shallower angle was often done with a piloted pull-through reamer and the final forcing cone cleaned up with laps, in situ. That would allow the longer taper to get at least into if not past the barrel constrictions commonly found in that part of the gun, which might well have been the main source of the beneficial effect. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

May 25, 2015, 05:22 PM	#9
jepp2 Senior Member Join Date: December 24, 2008 Location: Loveland, CO Posts: 1,476	My experience seems to be different. My understanding is that S&W uses an 8 degree cutter to cut the forcing cone. Kind of a compromise between what works best for jacketed (5 degrees) and cast lead (11 degrees). I have recut a few S&W's I use mostly for lead. I use an 11 degree cutter and it has certainly changed the angle that it came from the factory with. If you recast your barrel using Cerrosafe you will get a much more accurate mold to measure the angle with. __________________ NRA Benefactor Life member

May 26, 2015, 09:41 AM	#13
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Jepp2, It may be the age of my Smiths. Nothing recent. It can fool you, though. I have had the experience with a .357 Magnum barrel (one of my DW's) of chucking it in the lathe and finding a dial indicator showing a 3° angle over the center to rifling portion of the forcing cone. That, however, was created by erosion. The newer barrel's less worn forcing cone is flatter and 5°. If Cerrosafe isn't convenient, you can always apply mold release and put some quick set epoxy putty in for an impression. Exact dimensions don't matter, as the angle will be the same even if the diameters overall all are a tiny bit smaller. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle Last edited by Unclenick; May 26, 2015 at 03:57 PM.

May 24, 2015, 08:45 PM	#3
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Good idea.

May 24, 2015, 10:59 PM	#5
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	That's great Mr. Clark, but what is the factory angle of a M29...

May 25, 2015, 06:21 AM	#7
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Thank you.

May 26, 2015, 06:57 AM	#10
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Re: cerrosafe I have cerrosafe and know how to use it, the problem is pouring just the right amount in order to get the cast out, and have enough length to accurately measure the angle, plus if there is a bore restriction at the bbl threads it would have to be pounded out, I don't want to do that... The goal here is to make a lap to polish up what I have a little. I can make different angled laps until I match it, but I wanted to save time and materiel. I never dreamed that it would be this hard to find out the spec. I have posted this on four forums and the #'s have come back all over the place, "I think" and "probably" , So, I don't think anyone out there in internet land really KNOWS... Will be calling S&W today to see if THEY know... Thanks for the responses guys, I will let you know what Smith says.

May 26, 2015, 11:09 AM	#14
mikld Senior Member Join Date: February 7, 2009 Location: Southern Oregon! Posts: 2,891	http://www.saami.org/PubResources/CC...n%20Magnum.pdf Doesn't show forcing cone angle. The eleven degree, six minute dimension is for the chamber. Note to the right side of the drawing the noted "Barrel Face" and "Cylinder Face", but no angle called out... __________________ My Anchor is holding fast! I've learned how to stand on my own two knees...

May 26, 2015, 12:45 PM	#16
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Mikld: I noticed that, more non-info from FGufy. FGuffy: If you are not curious, I won't twist your arm to read anything I post. Going to see what S&W says when I get home.

May 26, 2015, 03:50 PM	#18
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	I have 3 S&W barrels, two are magnum types. Both have bulges, one has 6 jacketed bullets stacked one behind the other. It was not a matter of removing the bullets, the forcing cone had expanded .011". There were a number of 11 degree responses, and I wondered. F. Guffey