.375 H&H to .416 Remington Mag.?

black mamba · November 9, 2011, 05:47 PM

Since these cartridges both headspace on the belt, is it safe to simply neck up .375 H&H brass with a .416 Remington Mag sizer die, load an appropriate fireforming load and fire? Are any other steps necessary for safety considerations?

HiBC · November 9, 2011, 07:57 PM

I have not done it.
What you describe sounds like it will work,but you already knew that.

Necking up with standard reloading dies.in my experience,;There will be one side of the neck more prone to stretch.A softer or weaker side.This is where the stretch occurs,resulting in non-uniform neck wall thickness.This,in turn,makes for non-concentric ammo.

So,then,to fix that,a guy starys thinking about neck turning.

In my experience,the 416 Rem kicks pretty hard.Hard enough that its too much for me to enjoy shooting.I think you will need good neck tension to hold the bullets in the case.

I have had best luck necking up using the Bullseye/Cream of Wheat method.I get better neck uniformity.I have used it with 35 Whelen from 30-06 and blowing 30-40 Krag brass out straight for BPCR brass.
Once .405 Win brass and factory 35 Whelen came out,I do not require fireforming.If you need more on the Cream of Wheat method,ask.Use virgin brass.

Of course,best case,find new .416 Rem brass.

If a 416 is needed to shoot whatever you are shooting,I would not make any compromises in my ammo.

Next best might be to see if Huntington or someone offers magnum basic brass that you can neck down.

Good luck!

black mamba · November 9, 2011, 08:05 PM

BC, I already load for the .416 in new cases. I just happen to have a bunch of .375 H&H brass, and no longer a rifle chambered for it. I thought about forming it and using it for midrange lead gas-checked bullets for practice in the .416. I use a Wilson case trimmer, and would definitely square and chamfer the case mouths before any accuracy testing, but have never done neck reaming, not finding it necessary.

I took a bison a couple years ago with the Speer 350 gr semi-spitzer at 2600 fps. DRT.

HiBC · November 9, 2011, 08:45 PM

What you might try:
About 10% of a normal powder charge of Bullseye.You might need a couple more grains,but don't get crazy!It is Bullseye.

You can use a dipper.Put primed brass in your loading block.Put the Bullseye in one case.Fill it up to the neck with Cream of Wheat(not corn meal)I use a little wad of toilet paper on top .

If you have a controlled round feed rifle,remove the bolt,install the round in the bolt,put the loaded bolt back in the rifle,and shoot it,keep the muzzle up.

If its only semi-formed,add a little more powder.I don't think I'd go past 10 gr in the 375.

If the brass is too hard,they will split.

If it works,I think you will find nice,uniform necks.

I actually took an old chunk of Mauser bbl,about 8 in long,turned it to be a bbl insert for an old junky single shot break action 12 guage,drilled/reamed the bore out to .411 or so,and ran a 40-70 Sharps Straight reamer in.

Then I use the shotgun as a fire-forming tool.

November 9, 2011, 05:47 PM	#1
black mamba Senior Member Join Date: September 13, 2011 Location: SW Florida Posts: 890	.375 H&H to .416 Remington Mag.? Since these cartridges both headspace on the belt, is it safe to simply neck up .375 H&H brass with a .416 Remington Mag sizer die, load an appropriate fireforming load and fire? Are any other steps necessary for safety considerations?

November 9, 2011, 07:57 PM	#2
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	I have not done it. What you describe sounds like it will work,but you already knew that. Necking up with standard reloading dies.in my experience,;There will be one side of the neck more prone to stretch.A softer or weaker side.This is where the stretch occurs,resulting in non-uniform neck wall thickness.This,in turn,makes for non-concentric ammo. So,then,to fix that,a guy starys thinking about neck turning. In my experience,the 416 Rem kicks pretty hard.Hard enough that its too much for me to enjoy shooting.I think you will need good neck tension to hold the bullets in the case. I have had best luck necking up using the Bullseye/Cream of Wheat method.I get better neck uniformity.I have used it with 35 Whelen from 30-06 and blowing 30-40 Krag brass out straight for BPCR brass. Once .405 Win brass and factory 35 Whelen came out,I do not require fireforming.If you need more on the Cream of Wheat method,ask.Use virgin brass. Of course,best case,find new .416 Rem brass. If a 416 is needed to shoot whatever you are shooting,I would not make any compromises in my ammo. Next best might be to see if Huntington or someone offers magnum basic brass that you can neck down. Good luck!

November 9, 2011, 08:05 PM	#3
black mamba Senior Member Join Date: September 13, 2011 Location: SW Florida Posts: 890	BC, I already load for the .416 in new cases. I just happen to have a bunch of .375 H&H brass, and no longer a rifle chambered for it. I thought about forming it and using it for midrange lead gas-checked bullets for practice in the .416. I use a Wilson case trimmer, and would definitely square and chamfer the case mouths before any accuracy testing, but have never done neck reaming, not finding it necessary. I took a bison a couple years ago with the Speer 350 gr semi-spitzer at 2600 fps. DRT.

November 9, 2011, 08:45 PM	#4
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	What you might try: About 10% of a normal powder charge of Bullseye.You might need a couple more grains,but don't get crazy!It is Bullseye. You can use a dipper.Put primed brass in your loading block.Put the Bullseye in one case.Fill it up to the neck with Cream of Wheat(not corn meal)I use a little wad of toilet paper on top . If you have a controlled round feed rifle,remove the bolt,install the round in the bolt,put the loaded bolt back in the rifle,and shoot it,keep the muzzle up. If its only semi-formed,add a little more powder.I don't think I'd go past 10 gr in the 375. If the brass is too hard,they will split. If it works,I think you will find nice,uniform necks. I actually took an old chunk of Mauser bbl,about 8 in long,turned it to be a bbl insert for an old junky single shot break action 12 guage,drilled/reamed the bore out to .411 or so,and ran a 40-70 Sharps Straight reamer in. Then I use the shotgun as a fire-forming tool.