jsb's and AA fields work great in most AA rifles. u may find better esults from a different head size, my s400 groups better at 50 yds with 4.51's but another chap at my local club has the same rifle and it prefers 4.52's
TBh i find that jsb's seem to have alot less duff pelets per tin so i stick with them, unless i can only get AA- like atm
lewis