I am looking for a good gunsmith to ream out a Ruger .40 S$W cylinder to 10mm. Also would like to have Colt SAA .357 cylinders rechambered and line bored to .44Spl. and .45Colt. Any recommendations? Thanks.

I can do it.
Have the .357 cylinders been fitted to the respecive frames yet?
If not they will need to be heaspaced, cylinder gapped and endplay adjusted.
End play in a Colt SAA is easy, cylinder gap and headspace is generally more... involved.

Hi Rusty: Actually I have a few 2nd Gen. .357 Colts that I could either bore the .357 cyls or install new .44 Spl. or .45 Colt cyls. I just figured I could get much better accuracy by starting with the .357 cyls. I have new Colt bbls. The Rugers have .40 cyls. fitted and I'd like them bored to 10mm. Do you have a web site? Thanks.

Not to discount Rusty as It certainly can be done. But - Line-boring does not apply well to an existing cylinder, especially a Colt SAA. To do it right and get the most out of the process the revolver really needs to be rebuilt from the inside out and have a new cylinder made from scratch. Otherwise tolerance stack up defeats the purpose of line boring in the first place.

I'd get Hamilton Bowen's book and read the Chapter he devotes to it. And, for what its worth, he's (Bowen) told me that Line-boring a cylinder for a Colt SAA isn't really worth the cost and effort required considering the end result. I'd call him. He's built a few revolvers for me and my dad and is first class.

No, no website.
As David says the Colt would most likly need to have an over size bolt fitted to the cylinder and have a bolt guide fitted to the frame as well as the line boring to get the most out of the line bore job.
Working from a .357 cylinder is much more cost expideant than making a cylider from a blank. The custom form mills for making the ratchet and bolt cuts are rather expensive.
The hardened drill bushing used to guide the reamer from the barrel threads is plenty accurate for holding the location of the cylinder's exit bore to the c'line of the barrel threads.

I have not read Mr. Bowen's book, but I am very familiar with the process and if you would like to see an excellant representaion of what is entailed Jerry Kuhnhausen covers it in detail in his Colt SSA Revolvers shop manual. Its also quite thoroughly covered in his Ruger SA shop manual as well.

Try Jack Huntington. He's one 2 or 3 pistol smiths in the entire country building revolver cylinders completly in house. He has lots of staging reamers for such projects and does line boring on Rugers. Your Colt should be easy for him. 530-268-6877