thanks steve
as i thought the CHR is probably the better chain.
why?
well a chain is under stress at the tail end of the turning gera and at the fromnt end of the pulled gear. the better the fit the more links take the stress. if more take the stress the less wear there is going to be in a like-for-like example.
i have mentioned steve that i have seen many modern black blades where the top 2" have been shaved right down. i haven't done it yet but making 2 + 2 = 4 i guess the chain was going around the "IMOVABLE OBJECT" called the tensioner blade pivot bolt.
with the blade ground away in this area i think your chain would have fitted. i know this because in my sherco camgear assembly test there was a lot more loose chain when i pulled the blade out completely (and it had been under zero pressure).
so, i think i will now try and find regina CHR camchain whenever i can. and if i found your problem steve i would have filed some of the top 2" of blade off making the contact point nearer to halfway down. something i've brought up a few times.
regards
Taffy