Re: which .338??
I have a 338 Lapua Improved shooting a 32" Lilja barrel and I have gone over 3000fps easily. I maybe able to get 3050 or pushing 3100fps if I use the really slow powders. I use mine for accuracy only so I've never pushed it to see what it would do for speed. So keep that in mind. My case holds 120.6gr of H2O and a standard Lapua case holds 113gr and runs neck and neck with the 338 RUM. So if your shooting for 3100fps and using a standard Lapua or RUM case, you may be really stretching it in a 30-32" barrel lengths IMO. Now if you have a standard 338 Lapua with a 30-32" barrel and "only get 2900fps".... you still have a very potent long range rig and it's not the end of the world. Now if you stretch that barrel like Darryl has in the upper 30" range then 3100fps and maybe a little more could be easily obtainable with standard cases without any fireforming.
I would go with the Lapua myself due to the quality brass also. I measure all of my brass used in competition (Lapua and Norma brand) and I've never seen Remington brass even come close to holding a candle to the numbers these cases spin and weight in at. Now how much accuracy is the "better" cases worth.... that's an age old question that can't really be answered. So take that as you will. As for the Lazzeroni brass... of the few peices I've held in my hand (read very few!!) they didn't measure that great for wall thickness. It's my understanding that Bell Labs makes the Lazzeroni brass and I've seen some of the 404 Jeffery brass from Bell and it was junk to say the least. The walls varied in the .005-.007" and not the < .001" to .0000" like the Lapua and Norma 338 Lapua brass.
Just some thoughts,