Scope Rail Bed, only .0005 spring back??

[ricco1949]

I'm rebuilding my LRBR, 6x47 Lapua .100 Short, 700. Ya I know hard to be competitive with a RBRP.

EGW scope rail has less .0005 spring back on one end. I'm bedding it anyway and adding .125 pins.

I've not seen 700 bridges this straight before, some have as much as .005 spring back.

Do you think bedding was necessary?

 

[DaveTooley]

It won't take much effort to bed it. Once I recorded the height difference between the front and rear bridge on maybe 15 actions. I got as much as .014" difference. And that doesn't take into account the rolled off shape on the rear.

 

[ricco1949]

Thanks Dave. It's already bedded.

 

[AlNyhus]

100% contact always pays dividends.

 

[ricco1949]

100% contact always pays dividends.

Yup, 10-15 minutes of work can save lots of wondering.

 

[Bob3700]

I bed all my scope rails. Production tolerances - nothing is straight n perfect.

 

[LVLAaron]

How are y'all doing this? epoxy between action and rail, don't tighten the rail down hard, let it dry, and done?

 

[DShortt]

How are y'all doing this? epoxy between action and rail, don't tighten the rail down hard, let it dry, and done?

Yup.
I just lightly seat the screws. Very lightly.

 

[STS]

How are y'all doing this? epoxy between action and rail, don't tighten the rail down hard, let it dry, and done?

I don't tighten the rear of the rail at all. Let the rail find a stress free position and let the epoxy cure. Wax the screw holes and pop out the epoxy 'plugs' when you take it off.

 

[tobnpr]

It's not just the potential elevation difference front/back- it's also the conformity of the radius of the base to the receiver, which I've also found to be an issue using prussian blue. Bedding assures 100% contact of the base to the receiver. I've never "not" bedded a rail, takes minutes...

 

[Bob3700]

Yes, bed stress free. I also use steel rails so flex is at a minimum but bedding the rail is so easy. Eliminate another variable.

 

[ricco1949]

How are y'all doing this? epoxy between action and rail, don't tighten the rail down hard, let it dry, and done?

I determine which end springs up in the mill vise with indicator.

When I bed it I only snug the other end of rail and leave the springy end floating with screws in place with just enough tension for alignment only.

I bead blast the rail bottom for improved adhesion and use Johnson's Wax for release on the action. Dip screws in junky blue Brownell's release agent.

JB for the bedding but I thin it with epoxy thinner to a latex paint consistency and paint it on rail with a brush.

I add dowel pins after bedding cures.

 

[std7mag]

Hmmm, and here I've been using the green Loctite (the stuff used for bearing races) to bed my scope bases.

 

[AlNyhus]

On my work bench now.

 

[DShortt]

I do use a couple of coats of clear Kiwi shoe polish on the action just in case I decided I need the base off.
Otherwise, that image above looks very familiar.

 

[ricco1949]

Well the one I referred to my post #1 above ended up being a glue and screw.

I have always used Brownell's spray release agent..but this time I decided to use what I thought was Johnson's Wax. Wrong..it is Minwax Finishing Wax, that I use for final finish on cabinets, and it ain't no release agent, despite three coats. The rail is locked tight.

But that's fine anyway cause I had planned on glueing this one anyway in a second step.

Still added the pins though. The .125 pins are locked solid to both action and rail @ .1247 in this setup.

 

[davidjoe]

I JB weld these on with the idea that they will never be removed, steel Badger or Nightforce bases, and EGW steel for unusual sizes.

Over the years I have been doing that, none have ever needed to be removed for any reason, which is fortunate. Even the threads are locked with it.

This is the only way I know of for a rigid steel base, equal to the top strap of a revolver, to contribute to the rigidity of a repeater like a 700.

 

[ricco1949]

Yes David I plan on making future ones a permanent attachment. I particularly like that the pins are secure on both sides....no slip joint on either side.

 

[X Count]

How are y'all doing this? epoxy between action and rail, don't tighten the rail down hard, let it dry, and done?

Same process as an action but I don't use release agent on either action or rail. Its not usually something that needs to come apart regularly and if it does, its pretty easy to sit and iron on.

 

[AlNyhus]

All done. Holes are lightly chamfered and all edges sanded a skosh. Comes up to 'tight' instantly.

Good shootin' -Al