I have a Picatinny mount that fits, shotgun has a rail
If the picatinny mount is an adapter plate with RMSc footprint you would jut attach the optic to the plate mount then the plate to your rail. Adapter plates create more places for failure to lose zero, but if you like the slender smaller profile of the optic it's a reasonable sacrifice to make. Holosun are very high quality and I had no problems with my optic handling 12 gauge turkey load pressures.
I love mine on the Mossberg 940 but that is RSMc ready and the only shotgun I know that comes "micro dot" ready. Just use thread lock on your set screws and if you feel the gun took a jolt or have any reason to doubt the zero, just repattern it quickly prior to your next hunt.
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