Thanks everyone, yea one of the reason i asked was because I just don't know what a pellet is capable of at 150 yards, (I used to shooting .22 LRs, but i moved and not allowed to own a gun here) and watching all these videos of ppl shooting golf balls at 250 yards etc made me think that you could get a good grouping at 150yards, and i wanted to tighten up the group before moving up to my eventual aim, which was shooting at 250-300yards.
Initally i used the 24 grain JSBs and i was getting similar results, and then i got to work tuning by gun, opened up the transfer ports, and pellet probe to shoot the 34 grain at 900fps thinking the extra weight will make it more consistent & resistent to wind, thus giving me a much tighther grouping, but because result was kinda similar it made me think that i was doing something wrong.
The gun itself is great, its really accurate (When i adjust for the wind at 150yard, 90% of the time i can normally get within 1-2inch of the target, i shoot in the desert, so its really easy to see where the pellet lands, and the wind is very smooth due to the flat surface and consistent for about 10-15sec before it changes, then it changes massively then stays the same for another 10-15secs, its weird, but good).