Disco barrel bands...

[rcmark]

I was struggling with the accuracy of my disco.
I ordered a barrel from  Mac1 Airgun's.
After switching the barrels I noticed when installing the barrel bands the barrel was actually
being pulled 'down' by the barrel bands.

This solved the problem (Shimming the barrel band):
http://www.tko22.com/info.html


After I did this mod and ended up with these groups at 50 yards:

[Old Corps]

I realize this thread is old but I'm looking for some feedback on this topic. Shortly after getting my Disco I purchased a 2nd barrel band. I shimmed both bands as described in the TKO link and all was well. Lately every time I pick it up and shoot the poi has changed. It's high, it's low, it's left, it's right. It takes a while to figure out where the pellet is hitting 'cause it's off a lot but I get it zeroed (and the scope is near the middle of it's adjustment range, both ways). I can shoot many pellets through it and it stays right on. Next time I take it out same thing all over. I'm sure it's because the barrel has moved even though I try not to lean it directly on to the wall. I'm starting to think I'd be better off with just the one band right where Crosman put it. I know the barrel is supposed to be "free floating" and I tried to allow some movement when I put the 2nd band on and shimmed both of them. Out of frustration I've also tried snugging them both down so the barrel couldn't move but that didn't solve the problem either--I'm thinking because of expansion & retraction of the air tube.
Thoughts, experience with this much appreciated.

Ed

[56S]

Sounds like your PCP has self identified itself into a springer.  I had a similar problem and took the shim trick one step further.  My shims are .005" brass sheet covering the entire circumference of the barrel and tube with a small notch cut for the grub screw.  The Synco now hits consistent.  Friday it did fall over after stupidly leaning it against the ATV and reguired two clicks of windage to compensate at 30 yds. after the fall in the grass.

[kj]

to add to what 56s said. if yours is wood and tight on your tube that could account for poi shift. less likely with synthetic, but possible. if you think the swelling of the tube is pushing against the stock just remove some wood underneath . if you put one barrle band as close to the breech as possible, and try without the forward one.

just a couple ideas

peace
kj

[Old Corps]

Thanks for the replies gentlemen, appreciate it. Yeah, I think my Disco has been hanging around my break barrels too much. I guess I'll remove the front, extra band and see what happens. It was fine before I added the 2nd band, I thought that was the right thing to do.

Ed 

Oh, she's got a wood stock. The only way a Disco is sold as far as I know.