A compensator is a device attached to the end of the weapon barrel designed to vent gases and counter felt recoil when fired. For most weapons, a compensator is an add-on device that screws onto a threaded barrel and is not included in the overall barrel length.
Bianchi holsters are designed to work with the standard factory barrel dimensions. I.e., not including the addition of threaded barrels (unless specified) or compensators. In addition to the barrel’s length, the external dimensions of a compensator must be in line with the slide profile or lessor. Compensators wider or taller than the slide will not fit into the holster since they are based on a standard factory model. Often, open muzzle holsters can be the best choice for this weapon setup.