The 6.5x55 is a truly great cartridge. Other than on this board, it is an under appreciated cartridge. It is also an incredibly versatile round. It can be used for everything from ground squirrels to moose and elk as well as performing admirably on the target shooting scene.
The 6.5x55 surplus rifles are great buys and a lot of fun to shoot and collect. The more modern and stronger offerings are to be preferred for sporting purposes but that being said, the converted sporters do yeoman's service as well. The stronger commercial actions tend to be a little more forgiving and can be loaded to higher velocities. The commercial rifles also, mostly have shorter throats which are more suitable for lighter, shorter bullets.
In our area, we are spoiled by Del Selin's shop. He always has a decent selection of brass, bullets and powder as well as some hard to find commercially loaded ammunition. As was mentioned above, other than Norma, the other manufacturers of 6.5x55 only load 140 grain bullets.