Has any one used or have any good data on a 6.5x55 improved? Looking for comparisons, just how much better is it? Or is it?
Just for info, this would be built on a strong Mauser 98 action.
Also has any one found a particular brass to be easier to form?

Mauserkid.....

You might want to do a search on this topic. I posed the same type of questions some time back - Dan

6.5x55 AI is a very good case near that prefect water capacity in 6.5 mm and with 308 Win pressure level load ( 6.5x55 Sweden is a low pressure for old mauser design but in new gun or strong M98 no problem to run at 308 Win pressure level ) by this way you are not to far from 6.5/284 velocity but with less powder and less muzzle flash with short barrel .

some points to check before to use / chamber 6.5x55 AI

AI body taper doesn't like magazine box of the mauser 98 and feed is not easy to get ( but possible with work on rail and feeding ramp ).

Original 6.5x55 ( commercial ) chamber is broad with a very deeeep throat , best way is to cut a chamber with a real reamer design for accuracy and velocity .
If you need a drawing chamber I can share my drawing 6.5x55 AI DTC LRTT .
that a chamber tightened but able to shoot factory ammo with a modern target throat design .

Military chamber is over size even if the rifle M96 is very well made ( miltary guy doesn't reload ) .

you can use too the Jordan Design ( RCBS dies available )in 6.5x55 AI

Lapua make BR quality brass in 6.5x55 .

Enjoy 6.5 mm cal

Good Shooting

DAN TEC