Would you go 6.5x55 or 6.5X.284 in a M700 SA?

6.5X284, or a 260 Rem (6.5X308)

I don't even know why a 6.5X55 would be loaded to 2.8"???

Personally I�ve never really understood the hype about the 6.5x55. There are other much more potent cartridges that fit the same action on most rifles. Maybe I�ve misunderstood it but I would much rather take for an example the 270win or even go for a short action cartridge like the 260Rem.
The 6.5 can be used in 308 lenght actions (at least in some rifles) but is limited to 100gr bullets which makes it of very limited use to me.

GBF,
Ballistic coefficent of 6.5 bullets is one of the highest in absolute, precision aptitude, easiness in reloading and give to it the reputation that it has. For example it was an Olympic calibre.
And, excuse me, where did you learned about 100grs bullet? 6.5 is born with a heavy bullet, 160grs if I remember well, and actually gives its best in modern rifles using 120/140grs, with good results using 108grs bullet. 100 grs bullets are not suggested for 6.5x55, not even in a modern rifle that normally has a longer rifle step.
bye

Steve, what I said is that you can fit a 6.5 Swedish in a .308win action length BUT then you are limited to 100gr bullets since the action is too short for heavier bullets, thats what I said.
I know the BC is good in the 6.5mm bullets but .277 bullets can give as good BC and SD with only slightly heavier bullets and do make a far more potent weapon i my mind since you have the same lenght of action for the 6.5 SE and 270win. So I personally would definitely choose the 270 over the 6.5 Swedish.

Ok GBF,
considering a longer action to manage 79/80mm of 6.5x55 OAL or a .270, having passed a long time at the range where I saw a lot of both, I definitively choose 6.5x55. In the problem placing .270 Win has a worst position ( more problems, also when reloaded)than 6.5x55, and I choose it even if I like both, because both are excellent.
bye