or,.... you can cry once, buy Lapua 6BR brass, trim it to length and have brass you'll be able to pass down to future generations.
Going the reform route...you may or may not be successful. I had a bad experience reforming Lapua 7.62 X 39 into a 22 cal shorty....it was almost like the brass in the body of the case had memory...
You might want to read up on annealing.
I cant say I didnt have fun wasting a few hundred cases.