Unless you already have a stash of 760 barrels, you might look into the old Crosman Powermaster 66 or the new Recruit. They use a skinny barrel about 5/16" inside a steel tubing shroud. The older 66's were rifled, later models smoothbore, and the Recruits are all smoothbore. The 66 and the Recruit are just like 760's inside the receiver so they use a similar breach block. You can order new Recruit barrels direct from Crosman.
These would be longer than 760 barrels, but it would be easier to chop them to length than turn down a bunch of 7/16" barrels.
Hope this helps.
Anything that is complex is not useful and anything that is useful is simple
- Mikhail Kalashnikov
thank you that helps alot they want 60.00 dollar a tube to turn them down have a bunch of them but the 66 barrel willl work i just try it had one so took it apart an work like a charm will fill in on the project when done dennis