Somehow I doubt it. Thats 100fps faster than what Mr. Kirby lists as max for his .300AX with 210s which is a .30-338 Lapua Improved and should have just as much if not more case capacity with the ability to run at higher pressures. Granted the Lazz could have some freebore in it allowing for more velocity but Idk, thats way up there. I wouldnt say its impossible though. I read of a guy claiming 3400 with 210s with a 30" .300 Weatherby. Maybe you just got a real fast barrel, as that certainly happens quite a bit. You would have to get down and dirty to figure it out completely but its not the mysterious magic that some people like to think it is. You can figure out why your barrel is faster than others, though like I said it requires a bit of work ie whats the land diameter, groove diameter, groove width, leade angle, etc. And no, pulling a lead slug through the barrel will not give a truly accurate measurement like some like to think. Getting measurements that are accurate to .00000 and beyond is serious business, more than a lead slug is capable of.
Mr Frank Green goes into a bit of detail on what all specifications you would want to get on your barrel to end up with one that has a very good chance of being faster than most here: