Can a 375 'simply' be rebored to 400?

Just wondered what else would need to be done. Seems that any feeding issues would be minor since it all the same parent case

Might have a steal of a deal on a 375, but I don't need another 375.

Hmmm, thought someone would have chimed in by now.

Why is the redheaded step child of big bores?

Very little on it when searching the internet.

I tried hard searching for 400 H&H chamber prints, but could not find any. I'm layed up for a while with a bad knee, so I've got lots of time on my hands.
Matt.

Quick load has a 400 H&H Mag with a 0.410" bullet...also on Ammo Guide with a very long neck so that one ISN'T just a rechamber/rebore...the chamber would have to be shortened bit and the chamber recut.

You CAN have a reamer made to ANY spec, just about, so you could have one made to just enlarge the neck 375 neck to 0.400" OR 0.410-11" and give it your own name.

There are several alreadybeendone 400's using various belted mag and Jeffery's case iterations so why reinvent the wheel...and it would be an easy rebore/rebarrel to 416 Rem, 416 Ruger or Dakota depending on your receiver/brand.

Interesting thought for a one-off or actually very few around shooter.

Check out D'arcy Echols 404-375 wildcat.

quote:

Originally posted by NONAGONAGIN:
Quick load has a 400 H&H Mag with a 0.410" bullet...also on Ammo Guide with a very long neck so that one ISN'T just a rechamber/rebore...the chamber would have to be shortened bit and the chamber recut.

I figured as much, otherwise it would have been much more popular. Imagine reboring any ol .375 H&H, cleaning up the chamber and being good to go!

I wonder if the rails would need much work, if any to feed reliably, if you rebarreled a .375H&H.

A 300, 375, and 400 H&H would make quite the battery.

This is why the 404-375 is so cool.

quote:

Originally posted by Duckear:

quote:

Originally posted by NONAGONAGIN:
Quick load has a 400 H&H Mag with a 0.410" bullet...also on Ammo Guide with a very long neck so that one ISN'T just a rechamber/rebore...the chamber would have to be shortened bit and the chamber recut.

I figured as much, otherwise it would have been much more popular. Imagine reboring any ol .375 H&H, cleaning up the chamber and being good to go!

I wonder if the rails would need much work, if any to feed reliably, if you rebarreled a .375H&H.

A 300, 375, and 400 H&H would make quite the battery.

I had a 375 H&H Whitworth express rebarreled to 400 H&H. It was a very simple job and works great. I sold the original barrel and with that against the cost I don't think you could save much by trying to rebore.

Pierre van der Walt has a lot of information on the 400H&H in his book "African Dangerous Game Cartridges". He had one made for his son, first in Sth Africa. The book is also available on Kindle.

I have contemplated it, have a few 375H&H's and was thinking of making one a 400.

Be interested to follow your build.

Cheers, Chris

I'M the one who's gotta be different and do the strange things but with the several factory available 416 rifles and ammo I see no need to feed my wildcat self with a "puny" 400...

I built a Ruger M77 416 Taylor that does very well indeed with 350 and 400 gr slugs and isn't all that far behind the Rem or Ruger 416 so I can't even get excited about rechambering to those cases....plus the 3.35" length limitation, OK for the Ruger, but would keep me from going to 416 Rem in that receiver.

I can of course just limit the COAL but that also limits performance by reducing case volume in the Rem version.

I have a 375 H&H, Savage 375 Ruger, and 375 JDJ/9.5x62 and keep looking at the Savage to add the 416 Ruger and maybe a 338 Ruger to boot.

But...then again the 404-375 is also highly viable and already developed and is just a rebarrel away.

Basically the major problem I run into over the past 5-8 years is getting dies made...I waited almost a year for my last wildcat's dies so I've been doing the die thing FIRST, then the reamer, then the barrel or just sticking with already available off the shelf components. Somewhat azzbakards, but barrels and reamers haven't taken more than 2 months at the most and when I take a cylinder blank rather than waiting for contouring, it's even less time...Konntooring ain' no thang bro".

Jim Kobe here has done at least one 400 H&H, for a friend of mine. He's be a good one to contact.

I recently chambered up a 404/375H&H for a fellow in AK. I have done a few of the 400H&H's. Know that these are quite a bit different from each other. Supposedly, the 400H&H is a proprietary design by H&H. The 404 version is/was chambered with the 375 reamer piloted with the 404 pilot and then the neck was opened up.

Jim

See, I told ya he'd know! He's a lot smarter than he looks :-)

Seems like to me the better conversion would be go to a .416 Rem...The 404 H&H has been more of a failure than H&H wanted, and brass is not easy to come by and will be harder and harder to come by as time passes..Its another failed cartridge IMO....

at what H&H charges, they do not have to sell many.

They will have ammunition for their customers for eternity.

My rifle started with a new Win mod 70 in 375H&H, a Shilen barrel in .411 dia was chambered and fitted with irons and a Z6 1x6 scope. So far it seems to shoot everything I have put through it sub MOA.

A bit of a quiet moment so here goes, I hope it will help..Remember there is not any known pressure data out there for this cartridge....so this is trial and error so use caution using someone else data please. Start low work up 

Been shooting and loading for the 400H&H since 2011. Got the 400H&H bug from Duke McCaa and his son of Gulf Breeze Fire Arms after meeting them at the SCI show 2010. Gulf Breeze is a Dakota dealer and they have been selling 400H&H bored Dakota's for some time.
I have shot numerous animals with the 400 including a Cape Buff in Zim in 2012. Can't say enough about this cartridge other than there is no commercial loadings for this round or SAAMI specs, there are a few custom loaders like Superior that loads for the 400H&H.  Gulf Breeze worked very hard to get Barnes to load for the 400 H&H but they stopped at getting it SAAMI approved perhaps cost?   Gulf Breeze purchased all of Barnes’ brass and .411 dia 400gr TSX bullets (would like to get a box or two) they have also aquired .410 dia Woodlieghs with the proper jacket thickness for the faster velocities of the 400 H&H
It will push a 400gr bullet at 2400fps for the magical 5000lbs of energy and send a 300gr TSX down range at 2700fps. Perhaps it is the stock dynamics of my gun but, it's is a very soft shooter and the cartridge feeds extremely easy. Some of the .411 dia bullets on the market are, Barnes, Hornady, Northfork, CEB, Swift and Hawk. Varget, RL15 or H4895 will get you down range.



Brass..
Been buying it from Quality Cartridge http://www.qual-cart.com/ , or Midway.  375H&H brass is easily resized I’ve been re-sizing them in the 400 H&H re-sizing die then loading them with a light load to iron the wrinkles out of the neck.  I’ve been trimming to 2.840 If you resize 375H&H brass it will be a little short, but the neck is so long in this cartridge I don’t think it matters much.

Primers.. Magnum either CCI 250 or Federal 215

COAL... Dakota Rifles was cutting their 400H&H chambers to load Woodlieghs at an OAL of 3.540. this is what I had my chambers cut for.. The CEB Bullets I load out to 3.60 as they are a bore riding bullet as well as the TSX’s out to 3.60 as the have a very long ogive, if you think you can use some more powder space.

Bullets.. Hornaday.. makes a .411 300gr Spire point designed for the 405 Win good training and varmit bullet
              Barnes… makes a .411 300gr TSX,  
      Hawk ….makes a variety of .411 dia bullets I use these for practice
              CEB… I had Dan at CEB turn .411 dia bullets 400gr Solids and 370gr Raptors.  These bullets were especially designed for the cacrtridge demensions I gave them
              Woodliegh…. thier Bullets are .410 dia which would not seat in my cases if I had a collet sizing die I could fix this problem.  The Woodlieghs are also designed to perform at a lower velocity and I would not use them.
               NorthFork… makes a .411 360r SP have a couple of boxes waiting for loading. I am considering this bullet for a possible Buff and Eland hunt.



300gr Hornady and Barnes TSX COAL 3.540

H4895---ADI2206H
77gr.......2633
78gr.......2695
78.5gr.....2683
79gr.......2700
this load has been deadly on elk size game and an honest 300+ meter round. Using the Hornady 300 at 2700fps has become a favorite varmit/pest load as it turns everything into a grey mist..

I started out using the Reloader powders then switched to Hogdons
RL15 300gr TSX COAL 3.540
78gr......2620

I used 69grs RL15 and a 300gr Hornady to fireform 375H&H brass that had been re-sized in the 400H&H die.

400gr CEB Solid COAL 3.60
76gr Varget.....ADI2208.....2400

370gr CEB Raptor COAL 3.60
75gr Varget.....ADI2208.....2400
(I was REALLY hung up on getting 2400 fps and 5000lbs of energy out of this round)...

400gr Hawk Bullet COAL 3.540
Win 760
77grs.......2190...Fun practice load

I hope this helps at least it is a start..
I can cut and paste some Quick Load data that was done for me It was a good starting point but honestly I found it some what lacking but then again I had nothing to compare them to other than my chronograph..
Let me know if I can do anything else for you

To your original question I started my project with a new Win Mod 70 in 375 H&H rebarreled with a .411 Shilen barrel NEGC cut the chamber sis nothing to the rest of the action.
Sorry for my photo skills
A 400H&H and a 375 H&H