I recently got a Walker by Uberti and immediately decided to address the short arbor issue before shooting it. With a .0865" shim under the arbor I set the cone to cylinder gap at .0015". Whether it was fouling or heat I had to assist the cylinder several times and once it bound up to where I had to break down the gun. So I put a .088 shim under the arbor which gave me a .004" cone to cylinder gap and a .002" gap between the barrel and frame assembly which the wedge would close up but then it tightened up the cone to cylinder gap at the bottom (6 o'clock) so I put a .002" shim between the barrel and frame assembly. That brought the cone to cylinder to true with still a .004" gap. Nothing is permanent, nothing has been filed or changed which I like as it may all be subject to change in the future. Next step is a test shooting. This lead me to check the gap on some of my other guns. 1851 Navy .44 by Pietta is .007" and with Track Of the Wolf nipples is a very smooth running revolver. Uberti 1858 Remington BP (Slix Nipples) is .008" with base pin binding the only issue up around 24 rounds. Not that the cylinder binds, but the base pin becomes very difficult to remove if I let go much past that. So as part of my reloading procedure I pull the pin and give it wipe with bore butter or ballistol each time. My two cartridge guns, both Uberti, the 1858 Remington New Army Conversion and 1873 Evil Roy also have .008" cone to cylinder gaps.