Bill,
I bought lot# 35751/606387 from Grafs about 9mo ago, and at the time, they had only partial cases of two lots in stock. Matter of fact, they had only six 50rd boxes of the other lot, and it wound up shooting quite a bit better than the one I bought five bricks of. IOW, I blew over $500 on the poor lot. Won't happen again, I assure you. And since it's a case of very large ES that's causing the problem with this lot of the Bi Polar, it's not going to shoot any better in another rifle.
I hate to say this, but it seems to me that since the Lapua Test Center doesn't offer testing SK along with the Lapua ammo, I don't see any point in sending a rifle out there. I did, and wound up buying a couple of cases of the best lot of Center-X Dan found in my V-22. I've had time to shoot with this ammo, testing it out of two V-22s here at home - my original V-22 with a Krieger that I fitted & chambered, and a newer rifle with a Bartlein Kukri. The new Center-X is pretty good at 100yds, but only marginally better than the good lot of SK Rifle Match that I bought last year. I'll certainly do more shooting with this new lot of Center-X as the weather warms up, but to this point in time, I'm not seeing what I'd hoped with it at 210yds - it's a bit more consistent than SK Rifle Match, but not $3/box better...