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

[Gert Odendaal]

Good day members
I thought of sharing an interesting process. I previously fire formed .375 H&H Magnum brass to fit in my 404 Jeffery when I purchased it a few years ago. Reason being , there was not any brass available. Today I did the some process. I needed some brass to to shoot while practicing and do not want to use my new Hornady brass.
Step I
Anneal the brass .375 H&H Magnum brass.

Step two
Prime the brass
Step 3
Size the brass with the 404 Jeffery full sizer die. For this experiment I used 30 gn black powder and stuff maize meal into the brass .

I then load it into the 404 Jeffery and fire ..the first top part fire formed ...

Step 4
I then fire the brass:

Step 5
Re- load , this time I used 50gn , S335 with a cast bullet 350 gn and fire the brass...the whole brass fire formed to a .423 brass , 404 Jeffery...

Step 6:
Brass is totally converted to 404 Jeffery brass...will upload a photo tomorrow of the fire formed .375 H&H Magnum to a 404 Jeffery brass...

 

[BRICKBURN]

Interesting.

 

[Gert Odendaal]

End result, photo from previous experiment:

 

[stug]

Pretty impressive the way the belt disappears!

 

[8x68]

I was going to ask "where did the belt go?"

 

[Gert Odendaal]

The belt expanded exponentially... I did fire formed a few brass more today...now I have some practice brass without using my original Hornady and RWS brass...

 

[CAustin]

I didn't realize something like this could be done. Can this process damage the rifle?

 

[Ridgewalker]

Very interesting, but doesn't that leave a weak seam where the belt was? I assume (my first mistake) the brass doesn't melt together?

 

[Gert Odendaal]

No, CAustin, it is not possible for the rifle to be damaged..remember, the brass is flowing when the fire forming takes place..brass can stretch quite a lot..I used but 30 gn black powder and stuffed maize meal...there is no weak spot around the belt..I have done this process about four years back already and still shoot the brass I fire formed way back..
I will upload some photos of that process with more detail to see...

 

[Ridgewalker]

Gert, this is fascinating to me! I never heard nor would have thought this could be done!
So where is the typical failure mode for this brass? Belted cases usually fail near where the brass thins above the belt, or splitting necks sooner or later even after annealing.

 

[Gert Odendaal]

As mentioned previously..the past four years I am shooting these brass..so far no failures at all...remember belted cases head space on the belt..in this case the shoulder is the head space part...

 

[Ray B]

Do you use a tapered expander button to neck the .375" out to .423"?

 

[Gert Odendaal]

Johan Greyling explain to me the concept of fire-forming and flow of brass. He also explained that by using 15 gn MP 2OO in the brass stuffed with maze-meal is a safe procedure to blow out brass.

We did fire form the brass in two stages as well as run it through the 404 Jeffery sizing die. The first fire forming round showed the brass fire-formed from the neck to halve way of the brass.

I used the MP200 15 gn with maze-meal for the second time as well, and run it through the full length 404 sizer.

The third time I re-load 71 gn S335 and a 400 gn cast bullet to shoot . This ensured a fully formed .375 H&H Magnum brass fitting in my 404 Jeffery rifle.

 

[cagkt3]

Fascinating stuff, thanks Gert!

 

[Ridgewalker]

Thanks Gert! I'm still amazed! I appreciate all the explanations, pictures, etc.

 

[Ray B]

I'm wondering about the powders used. the first firing was with BlackPowder-does it matter if it's F, FF, FFF, or FFFF? The second firing was with MP200 and the third with S335. What powders that are available in the US could be substituted for these firings?

 

[Gert Odendaal]

Ray, the previous first experiment four years back was done with pistol powder, MP200, 15 gm...this weeks process Johan Greyling suggested I use black powder, FFg 30 gn...and then 50 gn S335 rifle powder...

 

[Ray B]

Since 375 H&H brass is readily available & 375 RUM is virtually non-existent, I'm wondering if the process noted above would work to expand the case out to RUM &/or Dakota specs.

 

[Gert Odendaal]

Ray, this was exactly the reason why I had to do this fire-forming process. I had a lot of .375 H&H brass available but not enough 404 Jeffery brass. The only way you will get an answer is to do a fire form process. I need to point out to the fact that many people warned me about how dangerous this process is....
Let us look at how dangerous this process is:
Annealing is the key to the success of this process.
Using a minute amount of pistol powder, since it is a fast burning powder that ensure expanding of the brass...

I used MP200 , 15 gn pistol powder in a large brass cartridge of a .375 H&H Magnum caliber .
I stuff the brass cartridge full of maize meal, really pressing it with a rod until it is filled up to the brim.

All that is left is to chamber it and fire it for the first time. At this stage I am not able to see where the danger in this process is.
This process is repeated twice. The first top half will form first, then the bottom halve forms. Both stages is competed by full sizing the brass with a 404 Jeffery die.

To fully form the brass I re-load with a minimum re-loading powder load seating a cast bullet and fire away..at this stage the fire form process is completed.

People pointed out to the fact that when using this fire formed .375 H&H Magnum brass to 404 Jeffery brass , the brass head will separate, the necks will disintegrate, the brass will blow out and wreck the action , causing damage to the hunter or people around him.

I am still using .375 H &H Magnum brass /404 Jeffery brass today, this has been used for the past five years, I still have to loose a fire formed brass up to today...

On the end of the day, this worked for me , due to a scarcity of 404 Jeffery brass I had to make a plan to enable me to shoot my 404 Jeffery rifle I bought five years ago.
I did not do this process to prove a point to critics ....

 

[ve7poi]

Thank you a very informative post
Must try sometime just for practice rounds and compare brass life with new 404J Hornady brass and WR brass