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Picatinny rail bedding question - flat rail vs flexing rail

metroplex

Sergeant of the Hide
Full Member
Minuteman
Sep 15, 2020
134
27
I just bought a new Nightforce 20MOA rail for my Bergara Premier HMR Pro 300WM (Long Action).

I checked on ways to see if it needs to be bedded, and if I snug down the forward most bolt, there's 0.31mm of clearance at the rear of the rail/receiver. You can see it kind of "spring board" when I press down on it. But 0.31mm is like 3 sheets of printer paper.

If I snug down the rearmost bolt, the front is snug. I can't fit anything under it.

I was curious if the rail is bent, so I placed the rail upside down on a very flat/true surface and sure enough the top of the Picatinny rail does not sit flat. There's clearance/light going through the center top of the rails. In other words, if you look at it right side up (the rails facing the sky) it'd be like the bottom of a "U" (exaggeration) towards the center.

To me, if I bolt down the front of the rail the rear is obviously going to sit high because the rail isn't flat. If I were to bed it this way, wouldn't it just be compensating for an untrue rail? And if I were to just send it and torque down all 4 screws, it might flatten it out?

Has anyone checked to see if their rails were flat/true before bedding?
 
b6graham, does this mean if you buy straight rails and actions that it will not be necessary to do any bedding? I ask because I am about to install my first rail on my first precision rifle and the bedding process is something I would like to avoid at my level of experience.
 
I finally went with the Area 419 Rem 700 Long Action 20 MOA rail. It is as straight as can be, and the 7075 T6 seems to be stiffer than the steel that Nightforce uses.

I did find that the recoil lug on the Area 419 secures snug against the Bergara HMR Pro receiver, and the machined groove behind the recoil lug "digs" into the stainless action. Plus the 4 screws are tapered, so they secure tightly into the tapered screw holes of the rail. Overall, very nicely made. Everything was dehorned and slick to the touch.
 
b6graham, does this mean if you buy straight rails and actions that it will not be necessary to do any bedding? I ask because I am about to install my first rail on my first precision rifle and the bedding process is something I would like to avoid at my level of experience.
Correct, bedding compound just fills up the empty void space should any be present so that when you tighten it down it doesnt bend. If there is no empty space due to quality machining then bedding wont have any where to go to work.

That said, dont be scared to bed a scope rail, youll find its very easy to do following all the youtube tips, watching the youtubes will take longer than bedding the thing.