Originally Posted by Welderboy250
I hear u on bedding the rail but is already taller than I expected so I'm not gonna bed the front higher. I guess maby ill take some off the rear section and then bed it that way. There needs to be a jig that clamps on the rail like a scope ring except it needs to go the full length so it can hold the rail from flexing up or down at one end while it is being bedded.
Unless the fit is really bad, we're only talking about gaps under the rail of ~10 or maybe 20 mils - not enough to make a significant height difference. If you remove material from the rear you are tilting the back of the rail down, which decreases elevation adjustment range. I would not remove any material from the base.
There is no need to hold the base rigid while the epoxy sets. The process I use works very well - even for poorly fitting bases. I prep the receiver in the normal way. I mask around the base area to prevent an epoxy mess. Then I apply clear wax to the receiver and silicone spray to the screw holes.
I scuff up the bottom of the base using emery cloth and then clean it with lacquer thinner. I apply JB Weld sparingly to the base mounting surfaces. Less is better. I leave a gap around the holes. I figure I can always repeat the process if there are large voids (rarely happens).
I position the base on the receiver, apply silicone to the screws and insert them. At this point I usually check alignment of the base to the barrel using an 18" steel ruler.
Here is the important part. The purpose of bedding is to maximize surface contact and minimize stress in the base. I gently tighten the base screws just enough to squeeze epoxy out of the gap and get the high points on the base to contact the receiver. "Gently" means less than 3 in-lbs of torque.
I go back and forth between screws, gently tightening each screw until I'm convinced the base is contacting the receiver somewhere on the front and back. Then I back off each screw 1/8 -1/4 turn to insure there is no stress in the base. This is critical. Some folks tighten the base screws at this point, which imparts stress and usually bends the base. Keeping the screws a bit loose during epoxy set allows the epoxy the fill the gaps while the base has no stress. Then I clean up excess epoxy using Q-tips.
I let the epoxy set overnight, pry it loose the next day, clean up the receiver, and remove excess epoxy from the corners of the base using a razor blade. Then I install the base, apply blue thread locker to the screws and torque the screws properly (20 in-lbs for #6 screws).
The bedding process takes about an hour. Works great every time.