Almost all revolvers work best with the same barrel/cylinder gap of from a minimum of .003 to a maximum of .012.
About .005 is about perfect.
The barrel/cylinder gap is cut with a special tool that puts a rod down the bore, and has a flat faced cutter that screws on the end.
The rod is pulled toward the muzzle and the rod is turned, cutting the end of the barrel.
Once the barrel/cylinder gap is set, the forcing cone MUST be re-cut and lapped with another special cutter and a brass lapping head.
The forcing cone is CRITICAL to accuracy and the outer diameter of the cone is what's important.
This CANNOT be "eyeballed".
To gage the cone, you use a special plug-gage that drops into the forcing cone and gages the outer diameter.
I'm saying all this to insure you know not to allow some "gunsmith" to use a file to hack off the end of the barrel and call it good.
The end of the barrel MUST be cut absolutely square with the bore, and NO ONE can do it right with a hand file.
Failing to properly cut, lap, and gage the forcing cone will produce a gun that's inaccurate and spits lead.