I would consider it a conversion not a convertible. Pinnacle says:
"My 9mm conversions are done using custom made specially ground reamers for re-chambering revolver cylinders, They are ground to the optimum taper and length to work perfectly for ease of extraction and seamless transition into the cylinder sizing area.
* Hotter loaded .357's may stick after the conversion"
TK puts it:
"Our work on cylinders rechambered to 9mm are LIMITED to our customer's using standard 9mm ammo or low pressure reloads, which are 34,000 - 35,000 psi chamber pressure or less. Same chamber pressures apply to firing of .38 SPL & .357 Mag. Examples of FACTORY Brands are: Winchester, Federal & Remington.
Absolutley NO 9mm Nato, 9mm +P or 9mm +P+, all which are far beyond the 34,000 - 35,000 psi chamber pressure our conversion is intended for. Usually 38,500 psi, which WILL Stick!
If you try to use these high pressure ammo, you will experience cases sticking in all chambers.
We cannot warranty our work, if you disregard our warning/notice on high pressure ammo.
When rechambered to 9mm the cylinder will still shoot NON-HIGH Pressure ammo, 38 SPL or 357 Mag with or without the proper moonclip."