How to mount a scope rail on a BFR and not shear screws?

[Whiterabbit]

So, I broke through all three screws, two #8's and one #6 on my BFR under recoil. Scope might be too heavy, I might not grip with an iron enough grip, I don't know. But it doesn't matter. It's clear I need to take extra measures.

I could drill and tap another 6-48 hole, but I don't want to do that.

Besides adding a drill and tap, do I have any other obvious answer? Loctite on the screws is not the answer because the screws did not back out, they just sheared off right at the base/topstrap boundary.

(actually they failed in tension, but I think that's an academic point for the purposes of this thread.)

I don't want to use an adhesive on the top strap unless I knew I could take every last bit of it off in the future if needed without 320 grit sandpaper.

SO! any thoughts?

[leebuilder]

Thats a dilly of a pickle. I would try a softer screw, sounds crazy, but have seen this before on several applications. If you over tourquing the screws too, done that.
Be safe

[Hannibal]

I have a 3-9x40 on mine chambered in .358 Win and have not had any trouble. What size scope do you have and what caliber is the rifle?

Edit - just noticed you are asking about a scope rail. I'm guessing the rail is not contoured to properly match your receiver.

[Whiterabbit]

it's a burris 2-6 and a BFR revolver. The rail is not only contoured perfectly to my flat top revolver, but it is a weigand base meaning it has sides that extend down the sides of the top as well as a section that keys into the rear sight cavity with zero clearance. It was designed and machined specific to the BFR revolver.

The cartridge is 460 S&W. the recoil is stout with 400-600 grain boolits.

[Hannibal]

I see. As suggested by leebuilder, I have seen grade 8 hardware fail under heavy shock loads. Do you know what grade the screws you used previously fall under?

In the situation I am thinking of, stainless hardware solved the problem. May or may not be an option in your location / situation. (?).

[leftiye]

Any looseness (with screws max tightened - I mean play here) allows the gun to pick up velocity before screw catches the momentum. Allows setup to beat screw to death. Have you ever thought about Poly choke adhesive (yeah, it's still out there), or epoxy? Maybe bed that part where the mount fits against the rear of the frame in the sight cutout.

[akajun]

Glue it down with epoxy. Acra glass works well and is pretty thin.

[leebuilder]

I see. As suggested by leebuilder, I have seen grade 8 hardware fail under heavy shock loads. Do you know what grade the screws you used previously fall under?

In the situation I am thinking of, stainless hardware solved the problem. May or may not be an option in your location / situation. (?).

the one application that sticks out in mind the most is a snow plow cutting edge. We would replace the bolts constantly, 20.00$ high grade fancy gold finish, till we ran out of them. Then went to a run of the mill 6.00$ bolt and it lasted the rest of the season. The right stainless screws would work.

[Mk42gunner]

Epoxy bed the rail to the frame, with correctly torqued screws. You say the rail has a lug that fits the rear sight cavity? Sounds like a good place to use as a recoil lug to me.

Most of the common epoxies can be removed with a suitable application of heat (heat gun or low flame from a propane torch) to break the bond, then you may or may not need to break out the sharpened popsicle sticks to remove the residue.

Robert

[country gent]

Bedding the rail to the mating surfaces will help some use a good bedding, Accra glass gel, Bisonite, plastic steel putty or similar. This makes for a coplete mating surface so screws only have to hold down and friction of complete mating retards movement alot. Bed the recoil lug into the rear sight cut also. I have had my contender in 357 herret shear scope mount screws bedding helped alot to stop it. Actually gluing it to the barrel was even better. If you decide on the gluing to gun MAKE ABSOLUTLY SURE screws have several coats of release agen and none in the holes. Make some studs with correct threads and nuts these can be installed in holes before epoxy mount slid over them and nuts to tension. Another thing to do is Call the maker of the rail explain issues and ask for information and cures.

[Menner]

first ting I would do is contact the manufacturer and see if they have a solution. next I would try different grade screws and use a torque wrench and make sure you have consistent pressure across the rail
I seen that you were not crazy about epoxying the rail down but that may be your best option
Tony

[lefty o]

red loctite the base to the gun. not the screws. if you want to take it off in the furture, kroil will disolve the loctite (its slow, but does work).