You could go with the 240 Wby case, essentially a 30/06 case with a belt and open it to 416. Not sure what the ballistics would be, but the '06 opened to handle a 416 would very nearly be a straight walled case without a shoulder, belt or rim to headspace on. The 240 Wby gives you the belt for headspacing.

The 240 Weatherby idea is very much like the 411 Hawk or Whelen with the adition of a belt and .005" more bullet dia. so I would think performance would be very close. Sean

I have a .416 HESAM, which is based on the .348 Winchester, modified to rimless. It is so close to the WSM basic case that you can run the WSM brass through a regular die, then once more through a swaging die that ever so slightly compresses the last .2" right before the rim. My rifle is based on a Ruger Mk II and it feeds like a champ, but only holds two down and one in the tube. It easily makes 2300 fps in a 22" barrel with Hornady 400 grain solids. You might get that magic 2400 fps out of the slightly larger WSM case and a 24" barrel???

My suggestion to anyone interested is to get a "Classic" Winchester model 70 in .300 or 325?? WSM (since they hold three down) and have Montana Rifleman bore you a barrel for the .416 WSM. Call them first. They've done it a bunch of times and may have some suggestions. The laminated stock version Modlel 70 would be my choice for strength reasons (I've already got plenty of "pretty" rifles). I checked on a chrome-moly (in the white) barrel on Friday (for a different caliber) and I believe that it was less than $225, threaded and short chambered. They can also give you advice about feeding problems.