Here is pic of 416 HSM second from left.
Can be 3.60" to 4.00" long, ac long one pictured.
Holds 280 gr ball powder under bullet. The
3.6" case can hold about 250gr under bullet.. In picture,
1st case is 416 HE, 2nd 416 HSM, 3rd 375 He, 4th 378 WEA.

416 HSM will get 400gr to 4000 without needing BMG action,
470 gr 3700, it may be the ultimate target, singleshot 416..
Case will work in fat bolt actions, with heavy enough barrel
to have good, milder, barrel harmonics and be under 50 lbs. Ed

[Linked Image]

Ed Hubel