The .222 and the .204 do the same job. The difference is that the .204 will do at 400 yrds.+ what the .222 does at 280 yrds. The guys are right about the .222 mag. being the parent case, but it`s not just necked dowm, the whole shoulder is blown fordward when fire forming so case capisity is more than the .222 mag. even after necking down. The biggest draw back to the .204 is that brass is not readially available yet, but it is starting to become more available. I shoot the .222 in a 14 in. barrel Contender also and the .204 in an Encore 26 in. barrel. Compairing the .204 to the .222 is not really a compairsion, the .204 will shoot alittle flatter than the .22-250 or the .220 Swift. Right now I have 3 - .17 cals., 5 - different .22 cal. rounds, and 2 - .25 cal. rifles for varminting, plus the .204. I think that the .204 is the best all around cal., especially if your reload. The .204 has pleanty of power and shoots the flattest of any of them. It is more fur friendly than any of the .22 cal. rounds, but lacks some to the .17`s. I wouldn`t worry about the .204 being a flash in the pan. There are too many different compaines chambering the round and too many others makeing bullets for .20 cal. now.