I was also looking at the 204 recently. Like all things AR-15 I found quickly there are options for 20 caliber platforms. It's great, but sometimes I wish there was only one so I don't have to think

. Anyway, started looking heavily at the 20x6.8. It's a rem 6.8spc case necked down to 20 caliber. The reason I'm considering this over the other options is I already have a 6x6.8 AR. I have the 6.8spc redding S die already and all I would need is the additional bushings and decapper for 20 cal. If I was starting from scratch I would have to seriously consider the 20 practical. Uses .223 brass, magazines, etc. However, since I'm setup for 6.8 that's that direction I will go if I decide to build yet another ar-15. I don't need another, but they are fun to build.