S310 Advice Please.

[Big gnat]

An old shooter I've had about 10 AA rifles over the years.
A friend came to me yesterday for help with the best looking S310 I've ever seen.
It's minted, but was leaking. Didn't take long to find the problems, basically it needed a few seals fitted.
Trouble is after rebuilding it can't seem to get the gun to cock properly. It's been up and down about 20 times.
The cocking lever isn't smooth as it should be.
Your advice would be appreciated.

[bgaltd]

loosen off the breech bolts and re-aline the breech with the hammer housing and valve housing . tighten them up a little bit at a time while working the bolt back and forth .