Has anyone here got one? I'm thinking of putting one together on a stainless classic M70. I've got a ton of .375 brass to form and it looks like a slick feeding round. There should be some reamers around and it's pretty simple to have a barrel rebored.

It should be VERY effective on large critters and DG. Will you be boring out a .375 HH ?

Yep. Gonna keep my current .375 and find a donor.

I’ve got one built by Dakota. If you want a rifle the same size as a .375 H&H that shoots a .40 caliber bullet it’s a good choice. A .416 Remington Magnum is probably a more practical choice but I believe the .400 H&H is a superior case design. Getting the correct diameter bullets is a bit of a challenge but if you want properly marked cases Quality Cartridge has them. Of course you can easily neck up .375 H&H cases, they’ll be a little short. I used mine on 6 Cape buffalo.

What bullet did you use on the buff? The 400 gr Swift A Frames look promising, as do the 300gr TSXs. The woodleighs apparently shouldn't be started more than 2200 fps. I agree it looks like a superior case for feeding.

Mostly I use a .411 diameter 400 gr Barnes TSX from a run they did a while back and it’s a great bullet. The other bullet I’ve used is a 400 gr North Fork cup point solid which if you are just shooting buffalo is great. I like to load a solid under one or two TSXs but I find managing two different loads to be a pain, with the cup point it’s the only bullet I use. It’s not as good for distance and you have to be careful in herds as it will shoot through a broadside bull. The Swift A-Frame is a .410 which probably does not make difference but the cannelure is in the wrong place for a crimp on my rifle.

I wondered about that 400gr barnes. There were references to them in reviews but they're no longer made. That would be the bullet to use I'm sure. If I do this it will be a brown bear gun so I need to find a bullet with some expansion.

I am curious about the "superior case for feeding" claim. Does the 416 Remington jam in Winchester Model 70's? From a rifle loony point of view it makes sense to me, From a practical point not as much.

I stated in my first reply on this topic that the .416 Remington is a more practical choice, in my opinion more because of the greater selection of .416 diameter bullets vs. .411s. I’ve got a Model 70 in .416 Rem built by the Winchester Custom Shop in the early 90s and it feeds and extracts just fine but not as slick as my .400 H&H Dakota. That does not mean much as it’s just a sample of two rifles. I do believe the long gently tapered cases of the .300, .375 and .400 H&H promote good feeding and easy extraction. Your right it is an example of “rifle loonyism”.

Yeah, I'm loony. I like the idea of a big rifle that allows me to tinker and do something different yet is very effective for it's purpose. This is all just an idea at this point. Bullet selection alone may force me to .416 diameter. As to feeding I think that all things being equal the H&Hs are more reliable.

The 400 H&H is appealing for an H&H cartridge fan. And certainly somewhat unique and would have to be effective. But, for my simple self, I would do a 416 Rem on the M70. I have a 416 Rem Classic Safari, and have had others prior to this one, and a Classic stainless that is a 22" re-barrel to a 416 Rem. The re-barrel in an HS Precision stock is a favorite. Both seem to feed fine.

The H&H cases certainly look as though they should feed slicker, but reality may depend of the individual rifle. I think every M70 that I have feeds very well regardless of cartridge. That even includes the sometimes scorned short mags.
I have a 375 H&H Classic stainless in a McMillan with a 22" barrel. Personally, I like the 416 Rem M70 combination best. Perhaps because it is slightly less barrel heavy.

You will have to cut more than a few threads off a 375 H&H barrel to get it to clean up for the 400 H&H re-bore and re-chamber, a new barrel would be better, chamber for 3.600" and mag box that will allow that length will be mighty handy, 400gr A-Frames should work, as will 400gr Woodleighs.

400gr bullets can be loaded to 2400 fps, I'd look for a comfortable 2150 fps.

CH4D has the dies, Quality cartridge has brass, Norma basic brass can be sized and trimmed to length too.

Be truly unique and go for the .465 H&H. Now THAT is an amazing cartridge. I'd love a Mauser in .465.

The more I look at things, the more sense a .416 Taylor makes for my purposes.

actually many years ago "maybe 30 years" Johnny Bell designed the 400 Bell Express on a Ruger Express rifle at Federal Cartridge and sent it to Bill Ruger,i still own the dies never heard anything from Ruger after that ?

Cartridges Of The World mentions the .400 H&H but doesn't give a lot of detail on it. I was trying to find out it's introduction date but to no avail.

2003 or thereabouts

Thanks.

Im planning to build one with a spare M70 300 Wby (I've got 2 NIB I bought for projects that didn't happen). No real need as Ive got a 400 Whelen nearly done and a 10.75x68 coming soon after. But, why not? It'll give me the 300/375/400 trio on New Haven M70's all in custom shop wood

Pierre van der Walt speeks well of this cartridge in a well informed segment of his African Dangerous Game Cartridges.

His son had the first rifle in South Africa in this cartridge

Weatherby used the H&H belted case for the smaller Weatherbys and then H&H used the 378 Wby as the basis for the 465 H&H bolt gun cartridge.

Just finished a 35 Whelen AI, and trying to decide if I want a 375 H&H or a 400 Whelen next.

Build a 400, a man can buy a damn nice new, semi, or full custom 375.

Agreed! The 400 should be a fun toy. I actually got my UPS notification an hour ago that it is due for delivery on Friday. Dies are a few weeks out.

A 400 would pair nicely with your 35WAI. What bullets are you planning to try in the 35? I have a 35 I've yet to fire, and a 2nd barrel yet to be installed and im starting to wonder if I should sell it all, minus the 1909 Argy action. Not a whole lot I need done between the 30-06 and 400. With 300 gr bullets you can hit 2400+ with ease, and 2250+ with 350's. Should easily be a 300 yard gun capable of killing anything in NA, and with 400's at 2150 it'll knock down any living creature. The 400 will probably make a bunch of my guns superfluous (but still fun to own like the 400H&H)

Forget the 400 and get yourself a 416!