As said JSB Heavies, mine seems particularly fond of Daystate Heavies....
JSB 8.44g
There's no messin' about when barrel cleaning a 1.77 - instead of those silly little felt wads you just wrap a J-cloth round a broom handle and shove it through.
I always try JSB Exacts in any new rifle I get, first.
Never had one yet thats shoots them bad.
Master Debater
Best is hard to say but JSB Exact is always a good bet.
H&N FTT always worked well in mine but it's down to the individual rifle\barrel\shooter.
Good luck, 45mm is one hell of a calibre for a sub-12 airgun.
Great Deals with : Dave Dee, Dozy, Beaky, Mick & Tich