Has anyone used the Norma Ballistic calculator from their website http://www.norma.cc/default.asp?Lang=2#
Are the calculations reasonably accurate? Downrange veloctiy, energy, trajectory, etc.?

I've only played with the Norma calculator. I use this one. http://www.eskimo.com/~jbm/ballistics/traj/traj.html

Just about any good calculator will get you in the ball park. Only way to know for sure is to shoot at the longer distance and see first hand.

The only time I've used it extensively was to prepare for a hunt in Wyoming. I worked up a 225 gr TSX load for a pre-64 Win M-70. Sighted in using trajectory data from the Norma program. I wanted a 300 yard zero but only have 100 yards to work with at home.

Got to Jackson Hole and took the rifle to the range. Three rounds on the 300 yard gong showed a 2" group exactly centered at the desired impact point. Took the rifle hunting.

The Norma program did a fine job for me.

I use ballistics program called PCB. I cant find the right download site now, but do a search. I have version 2.03 but only find version 1.8.

Its very good and give you nice tables.

Fieldtest your trajectory. Ballistics is a lot less predictable than these calculators give impression of. Wasnt the G1 table developed by the French army by testing smoothbore roundball cannons at least two hundred years ago?