Home Forums Hunting & Shooting Express Rifles and Big Bores Only .375/9.3×62

I read an article by Wayne van Zwoll where John Dustin built a Rem 760 in 9.3x62 necked up to .375.
I'm thinking of doing the same thing on a commercial FN action.
Before you all tell me just to do a regular 9.3 I'll tell you i would do just that but the barrel maker sent me a 375 barrel instead of a 9.3.
A new barrel is 12 weeks out.
Have any of you ever done this or another wildcat similar.
Looking for your experiences. I have heard stories of 375 and 400 Whelens not having enough shoulder to headspace correctly. Etc.

Could ask Mart and Med River they are both 400 Whelen shooters..mb

I would say do a .375 Ruger except I have tried it in the commercial FN magazine box
(in the form of a .458/.416 Ruger)
and the mag box is just a little too small to allow 3 in the box, it is just a 2+1 three-shooter.

The .375/9.3x62 is a much better fit (unless you want to get new bottom metal),
so it would be a 5+1 six-shooter at least with the commercial FN mag box.

Then why not a .375 Whelen ?
Brass, reloading dies and reamer availability ?

The 9.3 case had more volume and is easier to neck up than 35 Whelen.

Consider the 375 Whelen or 375 Whelen AI. Brass from 30-06 cases.

See my last post above

Dennis,

Mike Petrov did an outstanding job of debunking the headspace myth around the 400 Whelen in his articles. His work was the impetus for me to go forward with mine. The 400 W has enough shoulder on which to establish headspace. As does the 375 Whelen.

I had a Sedgley Springfield with a horrible bore that I had rebored to 375 Whelen. I truly regret parting with it but at the time felt it was redundant as I had a 35 and 400 Whelen.

I’d certainly go the easy route with your project. Dies for a 375 Whelen will be far easier to find. And while the keyboard ballisticians may show the 375/9.3x62 to be superior to the 375 Whelen, no practical application in the field will show one better than the other. They are ballistic twins for all intents and purposes.

You may find a sniff more resistance with 35 Whelen brass going to 375. Anneal the necks and have an extra helping of Wheaties that morning. You’ll never notice the difference.

I had no issues going from 30-06 to 375, let alone 35 to 375. Not sure why the problem.

I've done a lot of case forming. I just know from experience that going up .009" is easier than double that

But not more volume than the 35 Whelen AI (which can be extrapolated to the 375 WAI).
I shoot both 35 WAI and 9.3x62 and the Whelen AI has just a hair more volume than the 9.3.

The 9.3 case can be improved as well.

Is there a standard 9.5x62mm Mauser ?

The .375 Hawk started off as a 9.3x62mm necked up to 9.5mm bullet.
Original wildcatter used .30-06 brass in the X62mm chamber specs.
Got just a little bulge in the web area on firing.
He called it his tropical load for Africa, saying the British habitually used sloppy chambers for sure function
in adverse conditions.

By the time it became the .375 Hawk/Scovill it was done in a chamber spec-ed for
.30-06 case head diameter (0.471")
instead of the 9.3x62mm case head diameter (0.476").
No web bulges when using the more plentiful brass.

The .375 Hawk/Scovill seems just the ticket to me.
Necking up .35 Whelen to .375 Whelen is easy-peasy.
I base this on plenty of experience necking up .338 WinMag to .375/.338 WinMag,
and .338 Lapua Magnum to .375 Twister, aka 9.5 Tornado in Germany.
Anneal before necking up for greatest of ease.

The original .375 Whelen was called the .38 Whelen.
Headstamp alteration:
Easy to change the .35 into a .38 with your engraving tool.

I have been looking at reamer prints, the 375 Scoville is top of my list, although 35 Whelen bread isn't any easier to get than 9.3.

The excellent tapered Hornady expanders make necking up 06 brass a breeze. I don’t anneal first as I got a few collapsed cases. I do anneal after for the life cycle of the brass.
If you start with 06 cases, run them into a 338 wm Hornady die then go up to full size in a separate step works very well.
F01

Sir Dennis,
True. I never annealed new cases when going from .338 to .375, just too easy.
A little graphite dry lube inside necks does not hurt and might prevent collapsed shoulders in tougher jobs.
I use a set of two RCBS neck expanding dies that go from .30-cal to .375-cal in one step, then .375 to .45 in the second die.
For intermediate steps or steps beyond .45, just whatever die works, including a 50 BMG bullet point down, etc.
The old saw for annealing with difficult steps is:

Anneal before necking up.
Anneal after necking down.

The step from .358 to .375 is trivial, no annealing needed.
Even more so for 9.3mm (.366") to .375".
Anneal after the initial fire-forming and call it a brand new wildcat case.

As you were.
I looked in my "EUROPEAN SPORTING CARTRIDGES" and found a 9.5x57mm Mannlicher-Schoenauer based on the 8x57mm M88 Mauser case.
It was loaded by most European ammo companies and also popular in Britain as the ".375 Rimless Nitro Express."
No standard offering of 9.5x62mm Mauser could be found in the book, by W. B. Dixon.

I ordered a 375 Scoville reamer and gauge- I think, you never know with PT& G.

Geeze, I dunno what could be improved on the 9.3x62. All of them have a long, tapering throat, almost always allowing really any bullet to be loaded to out to full magazine length. We're talking 70-71 grains of ball powder under a 300 grain swift a-frame.

Only way this could be improved upon, would be 9.3x66 in something like a remington based standard action. You'd then be setting around 75 grains, with heavies loaded out to a longer magazine.

I like unique chambered rifles. Yours will be that. I suspect you’ll be able to use 375 Whelen or 375 Whelen AI loads and perhaps go up from there.
I really like my 375 Whelen AI - accurate and powerful.

It makes me a bit "concerned" going to some of these non-Western countries such as African countries with incorrect headstamps. Part of the benefit of having a medium bore or bigger is taking it on hunts to these sorts of places. Otherwise, you're just restricting yourself to North America and maybe one or two other places.