Originally Posted by chrisc
K, if you want some help then just let me know. I have a reg checker and also a spare new 55cm barrel that you could use to try to eliminate some possible problems.
Edit, also a few different batches of JSB's including different head sizes you could try.
Thanks Chris very kind of you I will let you know. Antony at redbecks has asked if they can have a look at it so just dropped it off today for a couple of days. I will keep you posted.