Has anyone on this forum experimented with the Rem. Ultra Mag case necked up to .416 cal. I have been toying with the idea of building a new rifle in this caliber but wondering if it would be enough better than the .416 Rem. Mag to justify custom dies and the extra expense? What are your opinions?

Check Z-hat. He has brass for the 416 ultra that he's been building

I don't think it would be any improvement over the 416 rem mag, and certainly wouldn't justify the exspense. The rem mag has enough case capicity to do what needs doing in 40 caliber, ie 400 gr @ 2400 fps. If you need a bigger case, then put the money for custom reamer and dies towards a 416 Rigby.

a 416 Ultra would be real close to the orignal 404 Jefferies,which was to my understanding an outstanding stopper.

it would do as much with lower pressure than the 416 Rem. which they say is a huge advantage in the African heat,even though I have never been.

Hawkeye.
I don't agree with Paul H. I think the .416 Rum would only miss .416Wby ballistics by 50 fps. or so. Go buy a .375 Rum bdl and send it to Z-hat with a .416 tube and see if he will put it together for you. Should be cheap for a big bore project. The brass is tough, and cheap compared to the .416 Rigby.
Saeed and the boys put together a 450 Vincent (RUM) that showed 2650fps with 500gr. Hornadys.
You would really need to lean on a 460Wby to get that velocity. Interesting ?
I think so too!

No we don't need more than 400gr @ 2400.
We may want it though.

Hawkeye,

Have you thought about the .416 Dakota? I am just looking at a dummy round for that cartridge, and it looks really good just sitting there. Cartridges of the World gives it 15% more powder capacity than the Remington, and quotes the factory loading as a 400 grain bullet at 2,450 fps.

jim dodd

I like the idea. Should be a no-brainer if you started with a 375 RUM action too. Reamers, dies and barrel, your on your way!

I'm still thinking of doing a 416 on the 300WSM cartridge for my son too.

Brent,

Jim Busha of Heavy Express was selling a "416 WSM", and one of the AR posters has one -- he thinks well of it. Jim closed down his business, but I think is still making custom rifles. If you get a rifle from him, you can get brass & dies.

I have his reloading manual if you want the ballistics.

jim

I'm with HunterJim on this one.
Look at the differences between the RUM and the long Dakota, you'll find there's maybe 3 grains of powder between them.
RUM at base - .546", at shoulder - .522"
Dakota base - .544", at shoulder - .527"
The Dakota is quite a bit longer, so you'll likely get more useable space out of it.
That, and the fact that there's already reamers/dies/brass for it....
But then, if it's not what you wnat none of that matters!

Thanks Guys for the info! I had never considered the Dakota round.

Hawkeye - I shoot both the .416 Dakota and a .416 Rigby. The Rigby has marginal legs beyond the Dakota case, however, the Dakota case fits in a standard length action and achieves 2550fps+ with a 410gr Woodleigh from a 24" tube. The Rigby can certainly top this, but I have never found the need to do so.

Dakota reamers, brass, dies, and load data are readily available.