My tsd sd702(well mb07) is not hopping my .3 gram bbs. I have just noticed that they are dropping after around 150ft. I have tried adjusting my hopup and it is not hopping them. The gun is advertised at 530 fps, which is believable due to the pull back. I have seen astkilo on youtube hitting a 250ft target on youtube, and his is hopping fine. Does any one have a clue as to what is happening?