Head Trauma,
Have you tried just resizing without the neck-expander ball in the FL resize die?
We have to do that with the 400 Whelen for some brass makes.
Works like a charm. Or get a second expander ball polished down a thou at a time
until it works with the Hornady brass?

The issue is not the expander. Resizing the Hornady brass in the Hornady dies without any expander ball at all still produces an over diameter case neck ID without sufficient tension to hold a seated bullet.

When I size the Hornady brass in the Hornady dies with the expander, it does not contact the inside of the case neck at all when the case is withdrawn from the die.

Funny thing, I can take the fired cases, "neck size" them in the RCBS die, seat a bullet and they chamber with little or no effort

This suggests that the Hornady neck wall thickness is significantly less than that of the Norma brass for which the dies were designed,
by Hornady Custom, using three fire-formed Norma 404 Jeffery cases.
So, use the correct brass or use your homemade neck sizer.

I used to use a cut-off .378 Wby FL sizer to neck size my .375/.338 Lapua (9.5x70 Tornado Magnum) cases before I got a set of dies made by Treibel.
That worked very well.

I don't have any Hornady brass, but will be sure to compare it to Norma, when I get the chance.

So I have read through a lot of this thread, and especially on the first few pages I see references to the 375/404 being way better than the 375 RUM. But I cant see why this is the case from anything that stands out to me in the thread. About the only difference I could see was a reference to a longer free bore in the 375 RUM. But its possible I am missing something here.

Genuinely interested to understand what makes the 375/404 a better option than the 375 RUM. Can someone enlighten me?

quote:

Originally posted by Bwana_500:
So I have read through a lot of this thread, and especially on the first few pages I see references to the 375/404 being way better than the 375 RUM. But I cant see why this is the case from anything that stands out to me in the thread. About the only difference I could see was a reference to a longer free bore in the 375 RUM. But its possible I am missing something here.

Genuinely interested to understand what makes the 375/404 a better option than the 375 RUM. Can someone enlighten me?

The .375/404 Jeffery Saeed of 2012 is functionally superior in case design, and ballistically equal, to the .375 RUM.

The 375/404JS has no micro-rebate of rim, has better neck length, has better shoulder angle, and has case capacity that is only about a grain of water less than the .375 RUM,
that being when you use the Norma 404 Jeffery brass, compared to the Remington .375 RUM brass.
It is like Swedish perfection compared to Chinese out-sourcing.

The free-bore thing:
That is a neutral as far as better or worse, for everything is relative, it depends, and there are no absolutes.

The throat of the .375/404 Jeffery Saeed of 2012 copies the .375 Weatherby Magnum throat of latest CIP specification.
It is what it is, and it ain't bad.

Yes, I figured they would be ballistically equal – there didnt seem to be enough difference in case volume for it to be otherwise. Thanks for the summary. I guess I need to go look at a set of reamer prints side by side.

I am not criticising your choice, but I am not sure that I could personally justify all the added cost of custom reamer, dies, etc over a 375 RUM.

Saeed has finally admitted:

quote:

Originally posted by Saeed:
RIP,

The dies you kindly sent work just fine, which means you have managed to reverse engineer my Top Secret Cartridge!

.375/404 Jeffery Saeed of 2012: Reamer by Manson, dies by Hornady.

The bullet: .375/300-grain GSC HV custom matched to your barrel groove and bore diameters.
Might even be better than a Walterhog.

Thanks for bringing this back to the top RIP. I was just wondering about it. I have been 110% engrossed in a new job, business travel and moving but am hopeful by the new year to get back to thinking about the next project.

Did you do any further load development with your two 375-404s?

Canuck,
No new developments.
Just like Saeed, stuck on same old load.
Just like Canuck, too many irons in the fire, posting this from a hotel in New York.