Unfortunately there is no definitive answer to your question as no two barrels behave in exactly the same way, what's good in one is not necessarily good in another. Unfortunately the only sure way to find the best pellet for your particular barrel is to beg from mates and shooting colleagues or buy as many different pellets in as many different head sizes as you can. You wouldn't believe just how much variation you can get in some barrels even when using the same pellet but in a different head size. I've been using JSB Exact 4.52's more or less since purchasing my Steyr about 9 months ago and must say that they have been ok out to say 30 yards but by 45 yards the grouping opens up a fair bit. I've just recently bought a few little packs of different pellets / head sizes from here: http://www.pelletperfect.co.uk to try in my Steyr and it was well worth it. The grouping with the 4.51's is noticeably tighter than from both the 4.52 and 4.53's!
Good luck with your search.
Last edited by J00SPD29; 13-11-2011 at 09:38 PM.
Reason: grammar
Steyr LG110 HP Hunting + Bushnell Elite 6500 2.5-16 x 42 Mil-Dot
BSA R-10 + Hawke Sidewinder Tactical 4.5-14 x 38 SR6
Kibworth SG