The 6.5's, with good bullets, all work well on moose and elk as well as the smaller species of cloven hoof ungulates.
Doesn't matter if it's a 6.5x54, 6.5 Swede, or one of the larger ones- they all work well.

For one, I do not condone long range shooting at big game animals due to problems with accuracy potential, wind & direction as well as game movement before impact. There are a myriad of unforeseen problems that can arise before or after the discharge of the rifle.

That is a personal belief and one I will not change. Within what I consider normal and long range, say out to 300yards (for those who actually practice out to that range(few and far between), any of the mentioned 6.5's will work just fine on the species noted.

I feel anything over a 60gr. case in .264 calibre to be larger than I'd want. 60gr. capacity would allow an improved short neck 6.5x57 or 6.5x.284. The one I put together for my daughter, with a 26" bl., would make 3,308fps with a 120gr. XLC bullet and shoot into 1/2" with those, at that speed. The ctg. made within 50fps of my 22" factory Winchester .264Mag, which required 20gr. MORE powder just to match my little round's speed with those bullets.