After reading an article about the 400 H&H in the 10th edition of the Cartridges of The World I was surprised to see that the guy who tested the prototyped H&H rifle claimed average speed of nearly 2500 fps with 400 grainer. Is that velocity possible because of the ultra long neck when the bullet is not protruding into the case? Does it mean less pressure than in 416 Remington?
What is your opinion or experience? I think here in this forum Tiggertate owns one rifle so chambered.
CZ

Less volume = more pressure. The laws of physics have not been repealed. It does not quite add up.

Lawndart is correct: the 416 Remington is an IMPROVED H&H case, therefore more capacity, and it can only safely push 2450 fps with 400 grain bullets. If one had a long throated 3.8" action, capable of 65,000 PSI, then maybe.

2350 fps at safe pressures is more likely.

Personally I have had excellent performance with 40 cal 400grain bullets at @2200fps on several game animals, including bear, lion, cape buff and elephants [a solid on the ele of course].