I have a used Burris SpeedBead mount for a Remington 870 12 gauge available for the taking if you want to try such a thing. Full disclosure, I didn't like it, but that's just me. But if you want it, send me a PM with your mailing info. Mount only, no FastFire red dot. Package is complete, nothing missing.
I ended up milling a spot on the 870's receiver for the Burris...