I talked to a guy in SA who has a youtube channel, and he and his buddy shoot 260 Rem. He swears he's getting 3K fps with 130 gr Berger VLD hunters with no signs of over-pressure. The 6.5 tapers more (wider at base, narrower at the bottom of the shoulder) than a 308 Win case, but it is 4 mm longer. If he's really getting 3K fps (Tikka T3 Varmint), I wonder if he really knows what signs of over-pressure actually look like.
These guys have some interesting loads for 6.5x55SE:
http://www.realguns.com/loads/655mmswede.htm. Their published velocities don't quite jive with IRL experience of another guy on this board (I'll let him announce if he wants).
I worked some 143 gr ELD-X/IMR-4831 loads up, to a little past hornady's published max, and shot them yesterday (Tikka T3 hunter). Been sort of busy since I got home from the range yesterday, but I'll put my calipers to the over-boosted brass and check the deltas between factory hornady brass and the other within-normal-limits loads I worked on. I'll let you guys know, but I don't expect to see anything unusual. Extraction certainly felt like the other brass, and there was no primer deformation or any other obvious indicators of over-pressure.