No 1 MK 3 rebuild, possible bedding issue

[Son]

Dave, you sound like you know what you are doing- so here's a possible quick fix. Can you make a spacer, probably start with something under a mm thick, like a tiny washer. Fit it on the thread end of the inner band screw and make the outside diameter the size of the large diameter of the screw. This will extend the length where the spring sits and may relieve the band enough to give it free play in the wood by Mr Horton's test and stop the barrel being pulled down hard.
The barrel should have contact in all the points I described earlier without the band tightened, what you need to achieve is when tightening the band you are not moving the barrel.
Then do another testfire.

Information

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[JBS]

Is it possible that over the many years of installing and removing the inner band screw that the threads have been worked back a bit farther than they should and this is allowing the screw to be turned down too much and bottoming out the inner band instead of letting it float on the spring ?

[yellowhousejake]

Dave, you sound like you know what you are doing- so here's a possible quick fix. Can you make a spacer, probably start with something under a mm thick, like a tiny washer. Fit it on the thread end of the inner band screw and make the outside diameter the size of the large diameter of the screw. This will extend the length where the spring sits and may relieve the band enough to give it free play in the wood by Mr Horton's test and stop the barrel being pulled down hard.
The barrel should have contact in all the points I described earlier without the band tightened, what you need to achieve is when tightening the band you are not moving the barrel.
Then do another testfire.

Sounds like a good thing to try, I was thinking along the same lines. My suspicion is that the unused replacement wood I acquired needs to have the inner band screw hole set to a proper depth, which I have not done. Further inspection this afternoon shows that the inner band spring is fully compressed when the screw shoulder meets the inner band.

Whether I remove wood from the inside or outside of the screw hole remains to be discovered. I think I need to take the wood from the outside of the hole so the inner band remains in the same position, and the spring is compressed less when the screw shoulder meets the inner band.

Does that make sense? Inside and outside of the hole? I am speaking of the wood shoulder inside the screw hole that the inner band spring rests against.
A washer may give me the results I am looking for and then I can use the required washer thickness to know how much wood to remove.

That is simple enough I may give it a try tomorrow.

JBS -- the forestock and all metal forward of the receiver are new, unused, armorer replacement parts. They wear no markings except the broad arrow. There is no wear on the screw.

DAve

[Son]

I wouldn't touch the wood just yet.
Does the barrel have downward pressure on the muzzle end of the foreend without the inner band screw fitted?
If the barrel pulls down when you tighten the inner band screw as you said earlier, then removing wood on the top side of the hole can only make it worse. Taking it from the outside would work, but how much do you have there to start with...?

If the bedding is correct with the inner band screw not fitted, then I wouldn't touch the wood again. Any alterations you make to the middle now are going to require alterations to the front and the back as well- virtually starting again!

Extend the collar on the screw a little until the tightening of the inner band does not pull the barrel down... or leave the spring out so it does nothing and then test fire it to check your poa against the poi. The inner band was only to help "tame" the barrel in the event of a foreend warping. In a correctly fitted foreend, it should do nothing.

[yellowhousejake]

I wouldn't touch the wood just yet.
Does the barrel have downward pressure on the muzzle end of the foreend without the inner band screw fitted?
If the barrel pulls down when you tighten the inner band screw as you said earlier, then removing wood on the top side of the hole can only make it worse. Taking it from the outside would work, but how much do you have there to start with...?

If the bedding is correct with the inner band screw not fitted, then I wouldn't touch the wood again. Any alterations you make to the middle now are going to require alterations to the front and the back as well- virtually starting again!

Extend the collar on the screw a little until the tightening of the inner band does not pull the barrel down... or leave the spring out so it does nothing and then test fire it to check your poa against the poi. The inner band was only to help "tame" the barrel in the event of a foreend warping. In a correctly fitted foreend, it should do nothing.

Well, I got a chance to work on the tuning a bit and these are my discoveries. First, nothing changed!

I verified the contact at the inner band and the nose.

I tried shooting with the inner band screw loosened, all the way to the point of removal.

I tried shooting with the nose cap stud spring removed.

I tried all combinations in between.

Still, I am inches high with the 25 yard sight-in target.

I am leaning towards the crown. It had a nick that I polished out. Possibly the crown was not straight in the first place.

I am also concerned that the Privi ammo may shoot differently, I just ordered a few boxes of Sierra 180 grain FB pro hunters to reload.

I can try making contact at the nose cap. Suggestions? I can stake the inside of the nose cap hole to provide contact, or I can add cork to the forearm tip. I only require barely 4 lbs of lift to pull the muzzle off the forearm so I can shim to make nosecap contact and still be less than 7 lbs required to lift the muzzle (I believe).

Again, thanks all for the generous help.

DAve