RE: 6mmx284 or 6.5x284???
Wolfkiller, I have a 6mm/284 and a wildcat 6.5 that slightly exceeds the 6.5/284 and both have there merits. Since you stated that you'll be using it on deer and lopes the 6.5 would be the ticket. The bullet weights jump up quite a bit in the .264's which will give you a little more energy down range. Another thing is that good 6.5 brass is available and it would'nt require the necking down process to .243. It really isnt no biggie, I have been forming regular 284 Win brass down to 6mm for years, it just takes more time.
Regardless of what caliber you pick, great bullets are available for both, my 6mm loves the now discontinued Barnes 75 X , 95 grain Ballistic Tip, 95 gr Partition while the 6.5 shoots all weights well... 95 gr V-Max, 107 gr MK, 120 gr Barnes X, 120 gr Ballistic Tip, 140 & 142 gr MK. The heavier bullets in .264 caliber are quite long and will take up powder space if they have to be seated deeply to fit in a magazine of a repeater....just a note for the stubby 284 case on a short action.
To some it up, if a person was going to hunt varmints more that antelope and deer the 6mm-284 is a great choice, while the 6.5-284 gets the nod if the bigger game is the quarry. Both can be and are good long range choices.
doubleA