Mystic, the 338LM bullet is a 300gr prototype with a crazy BC but it was built on a jacket that was too thin. We actually ripped them to shreds inside of 50yds which was amazing and too bad all at the same time.
The guys from Cheytac were actually interesting to talk to. I quizzed them on the coriolis effect and they say that when a bullets flight path crosses the mile mark while shooting north to south, some compensation is required.
The thing all these casings have in common is that the webbing is much stronger then casings like the Rigby.
One of the guys from Barrett was saying that Lee and RCBS already have dies available for the 416 which is great to hear.
I think, with time, these two new comers will hopefully gain enough popularity that we'll see the calibers in Canada. Anyone looking to crank out bullets for either two calibers will be in it as a long term investment in Canada at least. From the states is probably where we're going to have to go to get jacketted high BC bullets for these 2 heavy hitters.