With the durability, dimensional inter-changability of and generosity of the Krag chamber and head spacing on the rim, I rarely full length size before shooting new brass in my Krags. You can be assured that the brass will be fire formed after shooting it the first time.

Stick with lower or moderately charged loads the first time and I think you'll be safe. Krag brass has always been easy for me to work with.

Good luck. See what other people's experiences have been and give it a try.