You might try this website http://www.black-hills.com/ forthe Lapua stuff. The Armalite AR-30 is a nice bolt action version of the caliber as well. Handloading this one would not be a bad idea. The Ultra Mag is a pretty hot one as well and the ammo is alot more reasonable. Check the Chuck Hawks website out http://www.chuckhawks.com/super_338_Mags.htm
Good Luck!