Well i decided on the 6.5 grendel for long range and only want to buy the upper of this. I wanted a .204 ar to go varminting but that .204 lower wont fit on the 6.5 upper right? So if this is true i was going to get a complete .243so i had a lower for the 6.5 and was looking at the DPMS ar in 243 but didnt like the barrel on it and wanted to know if i could get a bigger bull barrel for it and also what are other AR companies who make it in the .243? Also does this( http://www.competitionshooting.com/catalogue/category33/product1215) look like a good upper in the 6.5 Grendel or does anybody know anything about it?