http://www.thehuntinglife.com/forums/topic/188282-bsa-ultra-reg-or-tench/
http://www.airgunbbs.com/showthread.php?645019-BSA-Ultra-SE
http://forums.pigeonwatch.co.uk/forums/topic/261556-new-to-the-scene-with-a-bsa-ultra-multi-177/
Or a thought would be. Read through the comments and contact the lads who actually fettle these rifles. That would be the better advice you could receive. Although I'm sure the lads have told you spot on.