You can go with the Marlin 336 base from Burris. It is a very low profile base and gives the FF the cleanest look IMO.
The bottom of the 336 base is flat, so it will rest on the two high points on either side of the rib relief on top of the action. It is a very light sight, so it doesn't need 100% contact. The two high spots will make full contact for the length of the base and provide a solid platform. Since the reciever is alloy, I would use red locktite to secure the two base screws.
You will need to have two holes drilled and tapped in your reciever for the 336 base. Once you have the base in hand, decide where you want to place the sight and have the smith drill/tap the action for that placement.
I'm having a SX2 drilled for a 336 base this year. It runs around 10 bucks a hole here to have the holes done. Shop around as some smiths will charge as much as 30 bucks a hole in some areas. For a smith that knows what he's doing, this is a very easy job.
You could go with the speed bead mount if you don't want to have the reciever drilled and tapped.
Good Luck
loder
