Hello again! (long time)
I had this question from a buddy of mine, who has some ideas wandering around in his head. And I promised to check around a bit. I did some searches here and there, but could not find anything to hold on to.
He is thinking of simply necking Norma .308 Win brass up to take .416 bullets. Is there any good info on such project?
Thanks!

Don't know about a 308 but there was a South African version using a 303 British case....the 416 Strauss.

Roger

There was the .411 Magnum. It's a .338 Win Mag necked up to .411. It's in Ackley's Vol II.

Yes, I`ve seen those you guys mentioned. Thanks. But nothing on the .308 case. I made a dummy, and it sure looks like it will be a minor shoulder. The idea is to make it work in short actions, as a sub/full power thumper. Maybe some bullets will need some "help" to expand by opening up the tip a bit.

As you have noted there could be similar problems the 400 Whelen had with the slight shoulder causing headspace problems if chambering and case forming and loading was not carefully done. A 30/06 or 308 case necked up to .416 bullet size would be even worse in this respect than the Whelen which is the 06 case necked up for a .405 bullet size.
The JD Jones .416-06 Improved got around the shoulder issue by using a 60 degree shoulder and less body taper. Likewise could be done to create a 416/08 Improved.

If wanting a .416 cartridge with grunt on a short action there is the .416/300WSM. Obviously this requires a short action with the larger bolt face for the WSM case but would provide a better cartridge than a 416/08 IMO and is just the fairly common 300WSM case necked up with no other change required.

let's ignore bullet choices, and we can all assume good cast and GC bullets ...

the 400 whelen problem is somewhat shortened (see what i did there?) by using the 308 case, as there would be available more shoulder v taper available in the shorter case - not much, but measurable

the next problem would be feeding it .. oh, not that .416 bullets wouldn't be suitable for the round, that's a different issue, but that to keep OAL on "normal" 416 bullets.. well, the groove to nose on 416 bullets tends to be right around 0.800 for 400gr bullets ... WOW, i just thought that through -- 200gr is considered to be pretty heavy for .308 (i know there's heavier, let me make the point) and DOUBLE the bullet weight would make for interesting pressure curves, and with the reduced case capacity ... okay, just checked length, and the 308 ALSO uses about 0.800 outside the case for max COAL - well, there's a good bit of shank to go into the case -- an exception would be the 350 ish bullets, which tend to lose all their weight in the shank --

comparative loads .. a 180 gr 308 is nominally 2600 fps .. at spec pressure -- i can't imagine (and not longer have quickload) how slow that would be with a 400gr bullet loaded to 2.8" . i'd guess for 1900 fps, wouldn't be surprised 300fps either way ....

400 blackout?

In Ken Waters book he built a 416 Express. (350 Rem Mag expanded to 416) I built one and shot it for a few years till a friend offered more $$$ than I had in it. I still have the reamer. If you wanted to build one I would be happy to lend you the reamer.

I've long been intrigued by the idea of a 416 on the 284 Winchester case,
in an AR-10.

I'm guessing that fatter case would still allow for 12 - 15 rounds in a
20 round mag.

In theory, it would just be a new barrel - Rim and length being the same as
308. However, you don't hear much about the 284 in an AR-10, let alone a
284 based wildcat.

The 9.3/284 was popular for a while.

Roger

There was a fellow in Australia that did a 416 on a 308 case. Cutting Edge Bullets created the 180gr Flatbase Raptor specifically at his request.

Under the heading wildcatters must wildcat.

quote:

Originally posted by wildmansix:
I still have the reamer. If you wanted to build one I would be happy to lend you the reamer.

Thanks, mate! But its only the .308 win based version i`m thinking of.
Thanks for interesting thoughts and tips so far.