I have a stock HW99S in .22 which has a lovely shooting cycle but I'm struggling to get it to group in a satisfactory manner (it's miles off my TX in .177). Thus far, I've tried H&N FTTs, AA Diabolo Fields (are these the same as JSB Exacts?)and RWS Superfields at 30 yards rested and I'm tending to get groups around the 3/4 inch-1 inch mark (some larger; others smaller) which I just don't think is at all satisfactory. Of the pellets I've tried, the RWS Superfields were rubbish and the FTTs and Diabolo Fields were about the same. I want to get some pellets to try as I'm sure this gun can shoot better than that, so which pellets should I get? I was thinking RWS Superdomes but have also heard good things about JSB Exact Express and Bisley Long Range Gold - are these worth a try? Alternatively (and I'm hoping I'm wrong here), am I naive to expect comparable accuracy to my .177 TX and 30 yards rested?

I absolutely love this gun's shot cycle and picked up a beautiful Hawke Airmax 2-7x32 which suits this rifle perfectly so I'm extremely keen to get this rig sorted and shooting as well as possible.