View Full Version : Revolver, line boring

08-10-2003, 08:08 AM
I'm not a revolver shooter, but I have heard of this process they call "line boreing", were all chambers are bored from the front of the gun, with special fixtures, and thus having the chambers aligned to the bore with better accuracy.

Anyone here done that, how?

Michael Az
08-10-2003, 02:00 PM
While I don't have any info on your question, I have often wondered how some revolvers can be so accurate with the bullet bouncing around the cylinder walls and then the forcing cone of the barrel. I have a Colt Python 8 3/8" that shoots better than some of my rifles!

08-10-2003, 03:41 PM
Smith & Wesson uses special fixtures to align the cylinder bores to the index cut on the cylinder. This is strictly an issue of proper positioning of the cylinder bores in relation to the indexing notches. They may have line bored back in he stone age - but no longer.

08-10-2003, 06:11 PM
I seem to remember some of the big dollar single actions being bored in this manner. Linebaugh and Freedom Arms for instance.
I don't know method, but can visualize a dummy barrel threaded to frame to pilot the boring tool.
Brownells and others sell range rods to check alignment of cylinder and barrel.

[This message has been edited by JCHannum (edited 08-10-2003).]

08-10-2003, 10:46 PM
I had a Lama .357 once that was made misaligned, they sure didn't line bore it. It would always spit a piece of lead out the left side, every shot. It's timing was all wrong. A little filing and it worked just right. I sold that hawgs legs the next day, never wanted to see it again.

08-11-2003, 01:29 AM
I took a tour of Freedom Arms plant a couple years ago, they thought I was just a mild-mannered tourist (evil grin)

They do align bore their revolver chambers, It seemed to me to be a rather elegant solution to a vexing problem.

To make a revolver cylinder that will drop right into place and index perfectly with the barrel take a level of QC that lesser shops just cannot afford

The cylinder with rough drilled chambers is fitted to the revolver frame and the bolt ( indexing device) is fitted, then a hardened bushing is screwed into the frame in the hole where the barrel will be.

The rough holes are then reamed to exact diameter and in perfect alignment to the barrel mounting hole.

All that is left then is to make sure that the threads on the barrel is concentric with the bore.

I remember thinking at the time "hell, I could do that in my little shop" I don't remember much of the rest of the tour as I was visulaizing making my own revolver- one of those round tuuit ideas.


08-11-2003, 01:33 AM
Forgot to add, for those who are not familiar with the proccess, the chambers of the revolver cylinder are then cut with a form reamer which is piloted to the hole you have previously reamed- this is done from the rear of the cylinder after removing it from the frame


08-11-2003, 02:43 AM
Hey, I had a Lama 38sp. that looked like the S&W 357. It did the same thing. (Spit lead from the left side) I bought it new in 1973 so I know it wasn't the same revolver... LOL. I sold it about 5 years ago to a security guard. I don't think I even put three boxes of rounds through it.

08-11-2003, 04:45 AM
Thanks all!
I can do this,I think, I'll use a d-dit drill in a guide barrel....There's plenty of info on line boring in "Advanced Machine work by Robert Smith"