Not really. Depends upon what type of gun you are using and its FPS and where you will play. For example I have one gun running at 340 FPS. I use .25 in it as it seems to me to give a little more range an helps punch trhough foiliage. For my support gun I use .2's as its a supprot gun running at around 320FPS and I tend to put a lot of rounds through it. My CCB gun I also use .2's at around 315FPS as its inside, close range and not to bothered about wind defelction.
So I would say that .2's are great for ccb and support guns. For woodland guns then you may need .25's as they are less likey to get deflected by wind, fly a bit further and can punch through leaves, however they are a bit slower than .2's so get to the target a fraction of a second later than a .2 would.
If you have a sniper then you need heavier weights still like .3, .4 or the like.
Basically I would get yourself a bag of .2's. Spend some time plinking in the back garden or at the site to set up your hop for the best spin, and have a blast using them. If youfancy trying .25's then you will need to set up the hop for them as well.
