It is the same rail used for the bps and gold also. So you can try to do a search for those as well. Unfortunately browning uses a proprietary scope base that is suited for weaver rings only and it only has two slots on it limiting it to scopes and red dots that take weaver rings. It is a terrible design. I tried to have EGW make me a custom picatinny base but after being jerked around by them for many months I gave up on them. I even tried making my own but again, browning uses an odd size proprietary screw for their base too!
I finally wound up just using the Browning base and putting a ff 3 on it. I had to file one of the slots so the burris would fit since the slot is rounded on the Browning base and I squared it off to fit for picatinny specs. It works, but the base is fairly thick and makes the sight sit higher than I want, but it does work. Eventually I took the base and sight off and just use a magnetic hi viz sight on the front and am quite pleased with that. Luckily my gun shot poa/poi but I had a check of a time trying to get an optic for that gun.
And, to top it off they way browning designed the rib prevents the use of most aftermarket rifle type sights. The maxus is a great gun, but for customization and aftermarket accessories it is a nightmare.
