I had an issue with my new sight not having enough adjustment down. It would only go down about half way through the site window. On my remmy with the speed bead i could lower it all the way past the bead on the front of the barrel, in fact I had it pointed directly at the bead so it looked like an illuminated bead.
I called Fast Fire last night and the CSR told me it's a known issue with mossbergs the the top of the receiver has a little rearward cant to it. Their suggestion was to call UM Tactical to get a 1 degree shim that goes between the FF mount and the FF sight.
The problem with this is it tilts the holes that the line up pins set in putting it in a bind. And the screws provided with the FF are too short then too. You have to use the shortest screws provided when you are mounting it to a picatinny rail because any longer and they will protrude and interfere with the rail.
Well I didn't like the idea of this and didn't want to order one and have to wait for it. I just happen to have a brand new package of JB Weld so I went to work fixing this problem the way it should be fixed.
I mounted the rail loosely and used a set of shims on the rear of the rail until I got the angel I was comfortable with which ended up being a .035" shim.
I then removed it all and applied a couple of coats of wax to the top of the receiver and the screws. I sanded the finish off the bottom of the rail to bare metal and cleaned it with lacquer thinner.
Then I mixed the JB Weld, smeared it on the rail then installed it back on the receiver loosely, slid the waxed shim under the back of the rail and tightened the front and rear screws nice and snug. Then I installed the other two waxed screws just snug to fill the holes so they wouldn't have any JB Weld in them. Don't tighten these two because it might cause the rail to flex.
Then I set it in my warm laundry room to cure for 24 hours.
Here's pics of the process, I'll update with more pics when it's done.
I know someone is gonna tell me they probably make shims to do this but I prefer this method over buying more stuff to do what I can do with stuff already on hand.
