Gents,
I have been shooting the 6.5x55 Swede cartridge for over 20 years and its my hands down favorite.
I own and shoot a host of other cartridges from 17 Remington to 458 Win Mag. I have more than a few 30 cal, 270 and 7mm rifles, a 358 Norma Mag (another swede), and a 375 H&H. I like them all, but I tend to reach for the 6.5 Swede more then any other. I doesnt kick much, shoot flat and the long, skinny bullets penetrate like a javelin.
Some of you have compared it to a 6.5x06. I have a beautiful 6.5x06 built on a custom Springfield 03 action and the metal and stock are stunning. It has a 25 inch Douglas super match barrel and it out distances the swede in angle of trajectory, but only by 100 yards.

My 6.5x55 is my ugliest rifle. It started life as a Turkish mauser ( large ring outside dimension and threaded for a small ring mauser 8x57 barrel, which equates to a really thick receiver ring. It had the flange at the front of the receiver turned off and the action squared, lugs lapped and a small ring Swedish Mauser barrel installed. The barrel was cut from 24" to 22", recrowned and the intermediate barrel step turned down to make for a smooth medium weight barrel. Twist is 1:7.5. Pretty tight and perfect for 140gr bullets. The barreled action sits in a epoxy/micro-ballon bed, in a Brown precision fiberglass stock, and the works are touched off by a Timney premium trigger.
Scope is a Leupold 3x9x42ish, VXIII. Nothin fancy. It is scarred from stem to stern and is darn ugly, but it shoots!!!
Since the throat is set up for military rounds and the round is shorter than a 270, you can seat the bullets to the depth of the throat and leave the balance for powder.
I have two loads that shine it this rifle.
First one is a 140gr (Nosler Partition, Sierra Game King, Remington Coreloc't, Etc., they all seem to group well) over 48gr of IMR 7828 or RE 21. Velocity runs around 2750fps. These loads hover at .5"-1" clover-leafers and is my standard deer round. Velocities aren't screaming, bullets mushroom perfectly and they don't tear up meat, shoots as flat a pancake to 250yds, and at 300 I put the crosshair on the backbone. Took that load and ugly rifle to Africa and used it for most stuff up to 550 lb critters.
Second one developed is a 120gr Ballistic tip over 48 grains of H414. velocity runs at 3,000 FPS and a one holer. Great long range antelope round and not half bad for coyotes. I have killed a few of deer, hogs, and coyotes with that combo. its a tad thin jacketed for hogs, so you have to ensure a clean lung shot. If you're worried use the 140gr and reset your scope a few clicks.
Neither of these loads are suitable for older M96 Swedish Mauser Infantry rifles. If you drop to 42-44 grains of either powder/bullet combo you should be ok.
These loads are MAX. Start with the M96 load and work up, checking for signs of pressure.... flattened primers, etc.
I hope you enjoy your Swede as much as I do. keep your powder dry and happy shooting.