Making 404Jeffery Brass

[Capt_Oscar]

In these trying times where brass has become scarce. I want to keep my 404Jeffery headstamped brass for Africa. So I wanted to make my own. While there is a thread on these forums about forming 404J from 375H&H; the smarter choice is forming from cases that use 404J as the parent case. I'm referring to Remington's Ultra Mag lineup. The differences in case dimensions is completely negligible to the point your can simply run 375 RUM through your 404J full length sizing die (assuming you have a tapered expander button). Load and shoot. You'll see in my loaded cases where the neck/shoulder joint was on the 375RUM, in the pics showing the loaded rounds.
The only, very minor issue, is the formed case comes in at 2.840" which won't allow for crimping the bullet. However, the neck on the 404 is so long it really doesn't need a crimp (in my opinion). If you still wanted it crimped, send 3 fired cases to Hornady explaining you want a custom factory crimp die - not the standard 404J die and they can make it for you (at a nominal cost).
Next question: how is performance compared to actual 404J brass. Well, keeping the same overall load length I experienced no velocity difference and accuracy was quite good.
Isn't 375RUM just as hard to find as 404J brass?? No, actually ADG makes 375RUM brass at a really decent price. Significantly cheaper then 404J brass.

 

[Capt_Oscar]

Loaded rounds

 

[Capt_Oscar]

Fired Rounds

 

[Capt_Oscar]

Had some virgin RP brass to experiment with. I did lose 3 cases out of 26 due to miscalculations on my part.

 

[Capt_Oscar]

Range Results (100yds)

 

[henkg]

Can same be done from .300 RUM?

 

[Capt_Oscar]

Can same be done from .300 RUM?

Yes, but coming up that far must be done in steps. Neck up to 0.338, anneal, neck up to 0.375, anneal, then full size for 404. If you try to do it in one shot you'll split a lot of case necks. Even 1 intermediate spot like going up to 0.375 and then 0.423 and you'll get very inconsistent neck wall thickness and still split quite a few.

 

[Huvius]

100% spot on!
This is the route I will take if I get another 404. I don't plan on it, but you never know...

Regarding this subject, I often wonder just what happened to all of the 404 (or 405Win, 35Win, etc.) or any other brass for that matter? There must be a good quantity of fired brass out there somewhere but maybe folks have their fired brass tucked away not knowing that there is a shortage of newly manufactured brass - not sure.

 

[Luvthunt]

Once again good info on this forum!

 

[Psm1975]

I have 70rds of 404 Jeffery that you’ve just helped me to ID. Thank you. I initially thought they were .404 Kynoch, but they’re the manufacturer.