More help with AR2078... barrel band loose

[Dukemeister]

I have been experimenting with different TP seals, and so the barrel has been off an on many times, maybe a dozen. Today I noticed that I could shift POI left and right over a range of about 2" from 10 yards (rested) by simply pushing the muzzle a bit either way. This obviously isn't good, or right. Barrel band screw is pretty tight.
What needs to be done to fix?
New O rings on barrel?
Second grub screw into breach?
Glue barrel band to CO2 tube?
Get metal barrel band...?
All of the above.... or which ones ?
Thanks.
Duke

[rsterne]

It's not the front sight rotating on the barrel, is it?.... I noticed that the globe sight can move quite a bit on the ARs....

Bob

[Dukemeister]

No, Bob. It's scoped... and I can see the barrel move and the band rotates a touch.

[rsterne]

Metal barrel band and setscrews should prevent it from rotating I would think.... I wouldn't glue it, too premanent....

Bob

[SeanMP]

There is a fair amount of play in the barrel breach connection. The set screw tightens the verical movement but the can still very a lot of horizontal play as it pivots on the set screw.

I have some brass shims in mine. They are a pain to install because you have to work them in right beside the loading ramp by rolling the barrel back and forth and pushing on the brass shim.

But once installed they eliminate that play you've got...I'm surprised Bob didn't remember him and Almaking fun of this on airgunhome..Brass Shim.jpg

HTH

[rsterne]

I must be losing it.... I dont remember the shims, or talking about them.... I've always figured that the QB barrel attachment was the weak point of the design.... Short attachment and enough clearance for O-rings....

Bob

[SeanMP]

Hahaha When Al asked what that shim was you suggested it was leftovers from lunch I feel exactly the same way. The breach connection needs to be longer or a second grub screw so it can't pivot

IMG087.jpgIMG089.jpg

I think you can see the glint of the brass shim just to the side of the loading ramp

[Dukemeister]

Thanks Sean and Bob... I think I'll try the 2nd grub screw and side shims (no cost solution), and maybe a metal barrel band ($$).

[AirGunEric]

Why not drill a couple holes in the side of the breech, tap and install setscrews there? Seems a better solution than a difficult to install shim that will need to be re-done everytime the barrel is removed and reinstalled.

[rsterne]

I'm wondering if there is room for a couple of 8-32 setscrews, one on each side, immediately in front of the loading port....

Bob