Fire forming: .375 H&H Magnum to .423 (404) Jeffery

[Ray B]

.I noticed the USA military are converting from the .338 Lapua to the .308 Norma Magnum ...

I think they are going with the 300 Norma Mag, Not the 308 Norma Mag. The 308 NM is very similar to the 30/338WM and has been around for over 50 years. The 300 NM is a recent design with a much larger case capacity. Whereas the 308 NM could be easily formed from 300 Win Mag, the 300 NM would present some real issues for forming.

 

[Gert Odendaal]

I think they are going with the 300 Norma Mag, Not the 308 Norma Mag. The 308 NM is very similar to the 30/338WM and has been around for over 50 years. The 300 NM is a recent design with a much larger case capacity. Whereas the 308 NM could be easily formed from 300 Win Mag, the 300 NM would present some real issues for forming.

Thank you Ray, this info is much appreciated , I wonder why they moved from the Lapua 338??

 

[Inline6]

Short answer, bullet technology.

 

[Gert Odendaal]

Short answer, bullet technology.

Good to hear from you again Inline..please explain the reason ? I was wondering about this new direction the USA Military took. I first thought it is more to do with a new company getting the contract to manufacture this new chassis and round .

 

[Jörg Krüger]

Jorg, dit is `n plesier, I do not thinkyou will get it for a better price since it is a specialized caliber..I noticed the USA military are converting from the .338 Lapua to the .308 Norma Magnum ...

The CIA(I think) did use the 308 Norma for a short while back in the day. Ray B is correct about the 300 Norma Mag, which is a 338 Norma necked down. Where the 338 Norma uses a 416 Rigby as a parent case. Now all that Norma needs to do is neck it to a 375 caliber. But that will most probably die as well.

 

[lwaters]

I heard it was the Hornady 300PRC that the military was going to.

I think they are going with the 300 Norma Mag, Not the 308 Norma Mag. The 308 NM is very similar to the 30/338WM and has been around for over 50 years. The 300 NM is a recent design with a much larger case capacity. Whereas the 308 NM could be easily formed from 300 Win Mag, the 300 NM would present some real issues for forming.

 

[Gert Odendaal]

I heard it was the Hornady 300PRC that the military was going to.

Then it will be possible to fire form the caliber from a 8x68S RWS case ...since the 8x68S case can be fire formed into the .375 Ruger as well...

 

[MarkB]

Just read this post. This site continues to wow me with the knowledge of its members. Masters of reloading, beats my normal reloading practices allowing me to shoot more and hunt with slightly more accurate handloads. Did have the silly idea some years ago to change my 375 H & H to 375 Weatherby. Then realized why?

Thanks for the continued education.

MB

 

[Gert Odendaal]

Mark, I had the notion to change my .375 H&H Magnum to an Ackley Improved ..Johan Greyling asked me this question : Why? I could not answer him..so I will refrain from going that route ...there is a saying : Why want to fix it when it is not broken??"

 

[Globalstar66]

@Gert Odendaal Resurrecting an old thread of yours I just stumbled on, and I found it fascinating.

I have a major dilemma - I own a Sauer 404 rifle, and have a new 404 Jeffery barrel for it, but Sauer stopped making the 404 Jeffery calibers, and I need a 404 Jeffery bolt head for this barrel, but cannot find one anywhere on the planet after over a years' worth of searching.

The 404 Jeffery brass' base is just a tad larger than the 375 H&H Mag. I do have a Magnum bolt head for the 375 H&H Caliber, but also cannot find a gunsmith willing to "open up" the bolt head to accept the larger 404 Jeffery case.

Your post has made me wonder if I should do what you did, ie form 404 Jeffery brass from 375 H&H brass - that way, presumably, the case would fit inside the slightly smaller 375 H&H's Magnum bolt head....??

Does anyone have any input in what I'm trying to explain here? Thanks!!!

 

[Ray B]

The recessed face bolts are difficult to open. Your idea to keep it at .532" may be the best Idea if you cannot find a .55 bolt face. If your barrel isn't already chambered for the Jeffery, one option would be a custom chambering that had the head with a .532" belt, then taper to the 404 shoulder, but that would be a wildcat and you may not want to deal with the hassle with case head stampings that don't match the rifle.

 

[Inline6]

@Gert Odendaal Resurrecting an old thread of yours I just stumbled on, and I found it fascinating.

I have a major dilemma - I own a Sauer 404 rifle, and have a new 404 Jeffery barrel for it, but Sauer stopped making the 404 Jeffery calibers, and I need a 404 Jeffery bolt head for this barrel, but cannot find one anywhere on the planet after over a years' worth of searching.

The 404 Jeffery brass' base is just a tad larger than the 375 H&H Mag. I do have a Magnum bolt head for the 375 H&H Caliber, but also cannot find a gunsmith willing to "open up" the bolt head to accept the larger 404 Jeffery case.

Your post has made me wonder if I should do what you did, ie form 404 Jeffery brass from 375 H&H brass - that way, presumably, the case would fit inside the slightly smaller 375 H&H's Magnum bolt head....??

Does anyone have any input in what I'm trying to explain here? Thanks!!!

Have you checked with LRI? They do really good work and they do things most other smith's will not. It worth asking them.

I have only been to Africa once, no one inspected my ammo. Not sure how common or uncommon that is.

 

[Globalstar66]

The recessed face bolts are difficult to open. Your idea to keep it at .532" may be the best Idea if you cannot find a .55 bolt face. If your barrel isn't already chambered for the Jeffery, one option would be a custom chambering that had the head with a .532" belt, then taper to the 404 shoulder, but that would be a wildcat and you may not want to deal with the hassle with case head stampings that don't match the rifle.

The barrel is a Sauer 404 factory 404 Jeffery barrel. I just cannot find a 404 Jeffery bolt head for it and Sauer won’t make it anymore. So my first thought was to get a gunsmith to look at “opening up” the bolt head ever so slightly so it accepted the 404 Jeff case… but that’s not been possible so far.

So when I read this thread - I thought it might just work to use 375 H&H brass like Gert did - that way I could use the Magnum bolt head that accepts the 375 H&H case…??

 

[Inline6]

The barrel is a Sauer 404 factory 404 Jeffery barrel. I just cannot find a 404 Jeffery bolt head for it and Sauer won’t make it anymore. So my first thought was to get a gunsmith to look at “opening up” the bolt head ever so slightly so it accepted the 404 Jeff case… but that’s not been possible so far.

So when I read this thread - I thought it might just work to use 375 H&H brass like Gert did - that way I could use the Magnum bolt head that accepts the 375 H&H case…??

Doing it the way Gert did will work with you current bolt.

The other thought would be to machine off the brass of a 404 case to match the bolt head you have now. You would just need to take a lot of measurements to confirm that would work. Could be an option.

 

[Globalstar66]

Doing it the way Gert did will work with you current bolt.

The other thought would be to machine off the brass of a 404 case to match the bolt head you have now. You would just need to take a lot of measurements to confirm that would work. Could be an option.

Thanks - I will get some research done on the options suggested!!!!

 

[Ray B]

As @Inline6 said would likely be the best way to do it. the only problem I see is if the bolt face is recessed so far that metal would need to be removed from the case ahead of the web. As long as only the rim and a little of the web are removed the case should still have sufficient strength. I would think that it wouldn't be a problem to have a little of the forward edge of the inside of the bold head removed so as to clear the case forward of the web.

 

[Globalstar66]

As @Inline6 said would likely be the best way to do it. the only problem I see is if the bolt face is recessed so far that metal would need to be removed from the case ahead of the web. As long as only the rim and a little of the web are removed the case should still have sufficient strength. I would think that it wouldn't be a problem to have a little of the forward edge of the inside of the bold head removed so as to clear the case forward of the web.

Thanks for your insights. I’m taking the bolt head with me to South Africa next week - there’s a custom gun builder there that build fantastic rifles and even build their own Mauser double square bridge actions in-house - hopefully they have some ideas.

 

[Ray B]

One other possibility: Reverse engineer the 375 Remington Ultra Mag. It is basically a 404 Jeffery that has had the rim turned down to .532 to fit a standard magnum bolt face, then necked down to .375 and shoulder pushed out. So it would seem possible to get RUM brass, run it through a neck expander, possibly two, to go from .375 to .423, then full length size with a 404 die to push the shoulder back and increase the body taper to Jeffery specs..

 

[Globalstar66]

One other possibility: Reverse engineer the 375 Remington Ultra Mag. It is basically a 404 Jeffery that has had the rim turned down to .532 to fit a standard magnum bolt face, then necked down to .375 and shoulder pushed out. So it would seem possible to get RUM brass, run it through a neck expander, possibly two, to go from .375 to .423, then full length size with a 404 die to push the shoulder back and increase the body taper to Jeffery specs..

That may just be a great option - thanks for the suggestion - something I will look into in detail!!!

 

[Gert Odendaal]

@Gert Odendaal Resurrecting an old thread of yours I just stumbled on, and I found it fascinating.

I have a major dilemma - I own a Sauer 404 rifle, and have a new 404 Jeffery barrel for it, but Sauer stopped making the 404 Jeffery calibers, and I need a 404 Jeffery bolt head for this barrel, but cannot find one anywhere on the planet after over a years' worth of searching.

The 404 Jeffery brass' base is just a tad larger than the 375 H&H Mag. I do have a Magnum bolt head for the 375 H&H Caliber, but also cannot find a gunsmith willing to "open up" the bolt head to accept the larger 404 Jeffery case.

Your post has made me wonder if I should do what you did, ie form 404 Jeffery brass from 375 H&H brass - that way, presumably, the case would fit inside the slightly smaller 375 H&H's Magnum bolt head....??

Does anyone have any input in what I'm trying to explain here? Thanks!!!

View attachment 465291

Just returned from the 1885 Era Black powder hunt. Options are: fire form or bring the bolt head to Johan Greyling so he can open it for you to accept the larger brass rim. Let me know what you want to do. I am in Witbank , Mpumalanga , South Africa and will always be able to assist any forum member who have a challenge or need. This invitation extends to the use of my house as a base to your hunting /visiting trip in SA. No charge at all..