CZ 455/457 barrel mounting doubts

[tuckybill]

Ok I'm a big CZ guy and I've got lots of Anschutzes also. I'm starting to have BIG doubts about the rigidity of the two grub screw barrel mounting system on the 455/457 CZs. With any oopsie they seem to lose zero to either side but hold the vertical. All my .22s have the same basic setup. BKL mounted Leupold scopes. Out of seven rifles shot today 3 Anschutzes were dead on zero from two/three months ago. All 4 CZ 457 had lost zero. One by alot. Two by a inch at 25yds and one by just a smig, call it 1/4 at 25 yards. I know some shooters glue them in with 609 loctite so I assume they have the same doubts that I'm getting to believe in.

I even whacked one barrel today with my hand and it seemed to move the impact about 3/4 inch to the right at 25 yards. These are all factory mounted not tinkered with barrels. What are your experiances with this issue? They seem to hold zero fine unless you give them a pretty good thump then they move latterally. I'm about to reach into my AR pile of goodies and haul out the 609

 

[justin amateur]

Factory mounted?

Might be the problem.

I swap barrels on my 455's from 22lr, 17hmr, 22wmr on a weekly basis.
Torque the barrel screws to 32 inch-lbs and the barrel is locked in tight.
Set the turrets to the settings from my log book for that receiver and scope.
Send a few shots to adjust to conditions, a click or two, and good to go.

Check that those screws are torqued from 30-34 inch-lbs, don't trust the factory install.
Stock to receiver screws no more than 24 inch-lbs.
Mag well screws tighten to contact then 1/8th turn.

 

[flatland1]

There were multiple reasons that convinced me to glue in when re-barreling a couple of my own 457s. Firstly, I didn't want to screw around with the set-up in the mill vise to cut the grub screw seats in the tenon. Then seeing how much metal is removed right over the chamber area, I couldn't help thinking about the probability that tight grub screws would have a negative effect by putting stress on the bbl tenon & action. Since I had no intentions of swapping barrels after going to the expense of buying, fitting, and chambering Shilen ratchet rifled bbls in 22LR, there was no reason not to go the glue-in route.