But with so many people already invested in the 416 Rem or 416 Rigby, the .400 Tembo seems to be at a disadvantage

Dan,

Not so sure about that. Hornady makes a 400 grain soft point, Speer makes a 350 grainer (leaving out the their special bullet) and Sierra does not make a bullet in 416 and Nosler make one bullet.

In a nutshell, the 416 is is dead when compared to 375 and 45.

Just check Woodleigh bullets.

So I can't see how people have all invested in 416.

Thus, there must be an opportunity somewhere.......but so far no one has got it up an running.

Currently., the 416 is dependent on CZ and Ruger.....and that only happens because of low pricing.

Mike