For sure is the .375 H&H Magnum a versatile round to work with..here is a thread about fire forming a a .375 H&H Magnum brass to fit into my 404 Jeffery ..after more than seven years I am still using this brass to shoot in the 404 Jeffery with out any brass failure at all.
Good day members.
Something interesting I like to share with you who are interested in fire-forming brass. A few years back I bought a 404 Jeffery hunting rifle. At that stage 404 Jeffery brass seems not so abundant in South Africa. I had a few eighty years old 404 rounds but was reluctant to shoot these old rounds.
While taking photos of the rifle and old rounds I received from the previous owner , I noticed some of the brass was .375 H&H Belted Magnum rounds and brass. I started wondering if it will be possible to fire form this brass to fit in my 404 Jeffery.
As usual, when contemplating an issue I do not have real answers for, I approached Johan Greyling, the gunsmith with all the answers.
Meanwhile I did post this question on an Afrikaans forum I was a member of that time, naturally all the "clever" people who have all the correct answers available , frequent this forum and this idea was opposed immediately . These "clever " gave measurements to state why this venture is a still born exercise that will never work. ( The knowledge of these "clever persons was determined by the quantity of rifles they possess..)
Meanwhile 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.
Phase Two:
I cut the fired formed brass open , as well as a standard .375 H&H Magnum brass and a standard 404 Jeffery brass.
This was done to take measurements of how the brass flow happened. I made use of a veneer to take some measurements.
Measuring:
I should mention the part which was a concern to the "clever" persons was the part above the belt. In the photo it seems as if the brass bulged out...when holding the brass in your hand this is not evident.
After the experiment I did shoot this brass a lot of times in the tunnel at the safe as well as on the BASA shooting days. This is two years + now and I still re-load this fire-formed brass and shoot it frequently. So far no cracks, head separations, blow outs, blow-ups, nothing the "clever all knowledgeable people " warned me about.
I did mentioned that it is good to posses a lot of theoretical knowledge, but it is even better to posses practical, hands on skills and knowledge.
As pointed out, at no stage was there any dangerous procedures done, since 15 gn of MP 200 stuffed with maze-meal can not in any situation pose danger when following these procedures...
I hope you enjoyed this thread....any inputs are more than welcome....
I did not remove the belt, the brass flows exponentially ...the belt does not make a difference when it fire-formed in the 404 Jeffery chamber. No head-spacing problems, primer pockets are normal, no primer pops out even when I load a full load and shoot the BASA shooting days, as mentioned before, I still re-load this brass and shoot full loads with Impala bullets, cast bullets and any other bullets I use in my 404 Jeffery rifle..
The 404 Jeffery caliber did get extremely popular the past two years, brass are available in most gun shops , I bought new Hornady brass and still re-load the 375/404 brass...
The main objective is to create a data basis regarding specific procedures to follow in regards to:
1) Creating brass for scarce caliber rifles ( Martini Henry brass)
2) Converting standard caliber brass to another standard /re-formed brass for a different caliber. .375 H&H Magnum brass to .375 Ruger brass/ 8x68 S brass to .375 Ruger brass.
3) Perfecting different methods/procedures that will be able to be replicated safely by fellow members.
4) Documenting every step through video clips/photos.
This is what we want to achieve and create
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 2
Prime the brass.
Step 3
Resize the brass with a 404 Jeffery full length sizer. To make the experiment interesting I used 30 gn of FFg black powder just to see how it will work. I then fill the brass up with maize-meal, using a dowl to really press the maize-meal down as compact as possible. I then load it into the 404 Jeffery chamber and pull the trigger.The top part, the first three centimeter blow out.
At the shooting tunnel, ready to do the first fire forming step...
Step 4
Fire the brass:
Step 5
Re-load , this time I used 50 gn of S335 and a cast bullet of 380 gn.
Step 6
Brass fire -formed to 404 Jeffery:
I did not manage to take a photo of the full sized fire formed brass...will do so when getting back to the Kluis.
Here is how it looks after fire forming is completed ...photos of previous experiment:
End result:
Conclusion:
FFg black powder 30 gn does not fire form brass as efficient as MP200, 15 gn there off.
Black powder soiled the brass ...while MP200 keep the brass clean.
After the last step, where I used 50 gn of S335 and a cast bullet of 380 gn I still had to use a full load of S335 to ensure a fully blown out 404 Jeffery brass from the .375 H&H Magnum brass...
Next time I will use MP 200 from the start..
Toby, you hit the nail on the head! I was thinking the same thing. 
