.357 Forcing Cone Length

[Catpop]

I looked at saami drawings, but the lenght of the .357 forcing cone was not spec ed. Is there a standard for this? I have a Ruger Blackhawk.
Thanks in advance.

 

[243winxb]

http://rugerforum.net/gunsmithing/36018-forcing-cone-question.html

See post 7

Why a 5 degree forcing cone?

357, Good question and I don't have a good answer ... only a speculation. My guess is because of the velocity loss and/or because all other Ruger SAs have a factory 5 degree cone. A 5 degree forcing cone will work pretty well with round nose bullets, assuming it is chamfered to the proper depth.

Herein lies the problem .... very few Rugers have a "perfect" forcing cone. The reason is quite simple .... The forcing cone is cut in thebarrel before it is installed. When the barrel is threaded into the frame, it is adjusted so the front sight is top dead center and the collar on the barrel is tight against the frame. This seldom happens the first try so the barrel is removed and the collar is cut back a precise amount. When it is screwed in again, the front sight lines up when the collar is tight. If the barrel installer takes too much off, he has to remove the barrel and take almost one full thread length off the collar. Each full barrel rotation accounts for 1/24 of an inch so thebarrel will extend too far into the frame. Sometimes it takes three tries to get a barrel indexed properly. This could account for as much as 1/8 of an inch. When the revolver is fit with a cylinder, a facing cutter is used to trim the rear of the barrel to get the proper B/C gap. When the rear of the barrel is cut back, it will remove a significant amount of the forcing cone. So .... some revolvers have normal depth cones and some have shallow cones ... all depending on how much the collar had to be cut back to index the barrel.

 

[243winxb]

Barrel indexing. Was thinking about the quote above.

In this day and age, hard to believe indexing is a problem.

S&W did pin barrels at one time to solve this problem. No longer.

I have to think Ruger can make and install a barrel without removing it a few times for fitting??

Just thinking out loud.