Alpha has dimensions different than Lapua and Norma. They have a different .200 datum diameter. Alpha even recommend a different reamer specs for the Alpha.
There is a lots of posts on accurate shooters about it. Stay away. Avoid problems with the Alpha 6BR brass.
Myself I have been asked to turn neck on a box of 50 necked up to .30, and was not impressed by the uniformity of the neck. Even if it was a limited samples, after that, for myself, no way I will buy that.
Petersen is a way better option in my view.
The Lapua 6BR is starting to show up in the US. Creedmoor Sport has it. They will trickle here by April was told. True or not ? Will have to wait and see I guess.