I was thinking of getting my W Mark V in 338/378 rechambered/rebarreled to 9.53 Saturn because of its ability to push the 300 grainers way past 3000fps. does Lazzeroni still make factory loaded ammunition for this chambering or do they just offer brass?

Looking at their web page they aren't selling ammo or the proper headstamped brass, just loading dies. Looks like you have to neck down the 10.57 (.416") Meteor or neck up the 8.59 (.338") Titan to form the 9.53 (.375") Saturn brass.

You know what maybe I will just stick with 338/378 and just be thankful of what I have........