Bedding a picatinny rail

[mjkten]

I have read several articles and posts, watched a couple videos too. While most use a release agent to separate the rail from the gun, others glue it down.
What I still have a question about is how to make sure you don't bend the rail by tightening the base screws through the point where the epoxy is filling the gap.
Any suggestions?
Thanks in advance, Mike.

 

[FearNoWind]

Mike,
I don't know what videos you've watched but this one, IMO, is perhaps the best I've ever seen on this subject:

https://www.youtube.com/watch?v=d6RopWI0-GE

If you hold the rail in contact with the action by pressing down on either end you should, depending on which end of the rail to which you apply finger pressure, see a small amount on light between the action and the opposite end of the rail.
That's the high end and the place where you need to concentrate the bedding compound (I use JB Weld).
The rest of the instructions are pretty clearly described in the video and, if you watch it several times, you'll get the hang of it pretty quickly.
I've learned that a good quality wax (Johnson's Paste Wax) works pretty well as a release agent and that "Q-tips" make clean up a snap. I also pack the holes in the end of the rail that receives the full coat of bedding material with clay to prevent the bedding agent from plugging those up. If the do get a little of the bedding compound them they clean up pretty well with a propertly sized drlll bit.

 

[mjkten]

Great video, probably the first one I've seen that didn't insert all the screws in while the epoxy was still liquid. I'll use this method with a few other ideas I've seen. Thanks!

 

[7magcreedmoor]

When I did my most recent DIY build on a Stevens 200, the rail I used had a small gap at the rear of the receiver, and also had no recoil lug on its underside. To deal with this I did a two-step process. First, bedding to fill the gap. Here is a youtube video on that procedure, which I followed pretty much exactly as you see John McQuay do it: https://www.youtube.com/watch?v=aoW5bHQqgis

Then to deal with the lack of a recoil lug, I did a "poor man's pin job", something I saw in John Burn's "Optimizing the factory rifle". After the epoxy pad from the above process was fully cured, I cut a small "X" in the top of the receiver between each pair of screw holes, and a corresponding "X" in the underside of my rail, then literally glued the whole thing together using more bedding compound. I don't intend to remove the rail for any reason, but I did put release agent on the screws just in case.

 

[J E Custom]

Great video, probably the first one I've seen that didn't insert all the screws in while the epoxy was still liquid. I'll use this method with a few other ideas I've seen. Thanks!

+1
Over the years I have tried different methods and this is the best way to get the rail mounted
correctly without any issues. It is simple, easy to do and the results always come out great if it is followed to the letter.

I also find that if you need to move the scope backwards or forward one slot (To set the eye relief
correctly the zero does not change enough to have to start over getting the POI in the same place.

Just mu opinion

J E CUSTOM

 

[stx]

Good Info!

 

[sambo3006]

In the video, it doesn't appear that he ever goes back and beds the front part of the rail base. I think that is a mistake. I can guarantee you that the front part of the rail base is not making 100% contact with the receiver. Would you bed an action to the stock the same way? Of course not. Eliminate as many variables as you can.

 

[mjkten]

In the video, it doesn't appear that he ever goes back and beds the front part of the rail base. I think that is a mistake.

Would you do the front after the rear has been bedded?
Would you perhaps bed the end of the rail that has the biggest gap first?
Curious.

 

[J E Custom]

Would you do the front after the rear has been bedded?
Would you perhaps bed the end of the rail that has the biggest gap first?
Curious.

Bed only the end that has a gap or doesn't fit. the other end will be good without bedding.
If you bed both ends it will not fit as good. unless you bed both ends, you have to do them at the same time (Tricky).

Keep it simple.

J E CUSTON

 

[sambo3006]

After the rear part is done, put some bedding compound on the front part then tighten the screws down. The bedding compound will be pushed out of the parts of the base that were making contact with the receiver. The areas that weren't making contact will have bedding compound on them and now the base is making 100% contact with the receiver when the screws are tightened. Simple as that.

 

[mjkten]

Well, I bedded the rear pad of the rail last night using JB Weld. I used Kiwi Neutral for the release agent, Plumbers Putty in the rail holes and taped up a couple areas just in case. My problem was impatience...at 11:30, it had been about 2.5 hours and I just had to check. Well, that was a mistake. It came off smeared on both surfaces. At least it could be scraped off.
I re-cleaned the surfaces, started all over, and went to bed. This morning it was sufficiently cured to remove the rail, I cleaned up the rail and placed it back on the rifle with the screws just finger tight. No more gap, no more movement. Good experience.
I have an old 700 ADL that I will bed in the stock eventually. I'll use different material for that.