Bedding check

[jsthntn247]

Just finished bedding a hunting rifle. With the gun inverted and the barrel in a vise, I checked for deflection with a dial micrometer and magnetic base. Screws were torqued to 40in/lbs. When letting the tension off on the front action I get almost a full turn with no movement then all of a sudden the mic drops .008. With the front screw tight there is 0 movement when loosening the rear screw. What went wrong? I used 2 points of contact, behind the rear action screw and tape on the barrel near the end of the channel. I've bedded probably 20 rifles this way and never had one check out over .002.

 

[eddief]

Are you running a barrel pad of bedding under the shank?

 

[jsthntn247]

Yes, there is a 1" pad. This is the first one I've done this way.

 

[Alex Wheeler]

I always check mine with the butt on the floor and the barrel vertical. I think the way your checking may be the problem. I dont like to use tape or surgical tubing to keep the action down, just gravity. Also make sure there isnt a piece of git under the action. Let us know what you find.

 

[jsthntn247]

I didn't use anything to keep the action down, just eased it down in the putty and let it rest on the 2 points and centered with headless screws. The action tightens down like it should, only takes 1/3 to 1/2 turn, does not feel like it's pulling down.

 

[JRS]

Without using, at the very least, tape, to hold the action in the stock, how were you able to keep the action from moving as the epoxy dried? Gravity alone will cause shifting problems as the epoxy cures.

 

['Freak]

Do you know from contact transfer of color that the bedding provides an equal 360 degrees of support to the area surrounding the rear action screw, and does re-tightening the front screw point the needle back at zero?

 

[jsthntn247]

Do you know from contact transfer of color that the bedding provides an equal 360 degrees of support to the area surrounding the rear action screw, and does re-tightening the front screw point the needle back at zero?

There were no voids around the rear screw and it appears to be making 100% contact. After I loosen the front screw (with rear screw tight) and the mic drops .008, I can then retighten it and it immediately returns to 0. With both screws tight to 40in/lbs I can adjust the wrench to 65 and slowly tighten them and the mic doesn't move on either one. With the old bedding in place, the more I tightened the more the mic would move and I could hear the stock creaking as it was being pulled down. It does not do this now.

 

['Freak]

One turn of a ¼-28 is .035” that you’re backing off the front screw before anything happens. Could be something about the rear screw is not squared up or aligned so all would be pulling absolutely perfectly perpendicular to the action. But then it’s not out enough for it to pull anything out of whack until the front end is relaxed a full 1/32” so then free to roam. How’s it shoot?

 

[jsthntn247]

The stock was already pillar bedded. I removed all the bedding down below the pillar height except for a small amount behind the rear pillar that I left for my one point of contact. It is possible that this was out of alignment and could be causing the issue? The barrel is centered in the channel now and it was not previously. The best I could get previoulsey was 1/2" groups but it would string horizontally. I will shoot it and see.

 

[gotcha]

Is it possible that your action screw/screws are making contact with the interior of the pillars? Also, as one DIY guy to another. I quit using tape to support barrels. I found the tape would compress as the bedding was drying. Couldn't figure out what was going on 'til I tried OLEFREAK's trick. Shimming BBL at end of fore end works better for me. Let us know how she shoots. Inquiring minds want to know

 

[jsthntn247]

Is it possible that your action screw/screws are making contact with the interior of the pillars? Also, as one DIY guy to another. I quit using tape to support barrels. I found the tape would compress as the bedding was drying. Couldn't figure out what was going on 'til I tried OLEFREAK's trick. Shimming BBL at end of fore end works better for me. Let us know how she shoots. Inquiring minds want to know

What do you shim with? I will look to see if I can see anything touching the pilar.

 

[gotcha]

Hi jsthntn247, I use a piece of 1/4 in. Delrin. Cut it to shallow angle like a wedge. I can adjust BBL. height by sliding fore and aft at tip of fore end. Tape the shim to the barrel when you reach final fit so you can duplicate the "setting". Raising or lowering the barrel too much can cause action screws to contact interior of pillars. Buyer beware Dale