I'm a certified gun nut and closet gunsmith, who does outfitting in a 2,100 sq mile territory we have just south of the Alaska border in British Columbia. Not unusual to run into a dozen coastal grizzly / browns a day and always have been seeking the ultimate bear rifle, as any good bear hunter and gun nut ought to.

I'd swung the spectrum, from a .505 Gibbs for the fun of it to .308 carbines, and even just a Glock 10mm for fish guiding and light duty like mountain goat hunting where bears are few. The two issues I always struggled to get to correlate were gun weight, and terminal effect. I separate terminal effect from power as I think they're slightly different considerations.

For a long while I carried a .375 H&H Merkel double rifle, with only three complaints; weather resistance, having to carry it cocked (a K gun could fix that), and weight. Terminal effect was impressive, handling and size fantastic, and I am heavily committed to the .375 H&H on the reload bench using it extensively at home and in Africa.

I started the quest for the perfect rifle in the custom realm with a Satterlee titanium M98 action, chambered in 9.5x57, finding it too slow for the shock I wanted to see on bears. Rifle was great, cartridge fell just short. In a perfect world I like bullet impacts on game at 2,400fps or above, and certainly above 2,200fps, I've seen a distinct uptick in performance at those thresholds. It's also what the FBI found to be the phase shift in terminal effect relative to velocity, above 2,200fps stretch cavities cause radiating tissue damage, below 2,200fps the stretch cavity is just temporary and doesn't cause the same damage. This is another argument.

As time and miles with a rifle in hand wore on, I knew I wanted a 6 1/2lb or less rifle, that launched a heavy bullet (250+ grains) over 2,500fps at the muzzle to meet my challengers at 2,400. I didn't want to exceed this either as recoil starts to climb, and while I shoot much worse, I envisioned this as a super comfortable and friendly jack of all trades guide rifle I'd reach for in any event. This wreaked of .375 Whelen, and I started to build one.

Dies, reamer, and dummy cartridges in hand I loaded my favourite .375 bullets which are all pointy, to find none kindly fit my mag and let me get near the lands with modern bullets. Round nose would be no issue, but as the jack of all trades rifle I wanted this to be able to take a 400 yard follow up shot on a goat when required and get there in reasonable fashion. I looked at my dummy round... and was fixated on the long .30-06 neck, that was doing nothing for me in this application. I picked up a 9.5x57 case from the Satterlee, and figured why not push the shoulder to the .30-06 position, blow it out and steepen it a bit to retain the case capacity, and shorten that neck?

The end result was the .375 Kemano, named for my best bear river, pictured below, and a bear therefrom. It's a 57mm case with the .30-06's shoulder position, steepened to 35 degrees and blown out to Gibbs proportions. I've had PTG make a real reamer and gauges, but the first chamber used three reamers, first a .30-06 for the initial shoulder and mock up, then a 9.5x57 to cut the throat and neck, and finally my .25 Gibbs reamer with the .375 pilot to cut the shoulder and body.

It fits five down in my Mauser magazine, lets me seat pointy bullets like the 260gr Accubond I'm shooting at 2,550fps out and still fit the mag, and has positive headspace with its sharpened shoulder. Is it doing anything new? No but it's perfect for what I do, it also drops bears like a bloody sledge hammer and is easy on the shoulder. I call it accidental as it was an evolution not a plan from the get go, and I used a fistful of reamers to make it happen all of which I already had. CH4D is making me a couple sets of dies now, and I just started headstamping my brass- I think that makes it rather official in my little world as my new favourite guiding cartridge.

I should note, for forming brass I adopted an odd technique- fire a standard .30-06 in the chamber and you get a .375 Kemano case with a 1/4" of extra neck. Trim that off, load and go. I set the headspace for a slight crush on a standard .30-06 to allow that.

-Angus

Looks cool.
That steep shoulder makes it look like a 416 Rigby.

Should work

She’s got two black bears to her name and both fell face to paws, same thing they do to my .375 H&H. I don’t think the bears can tell the difference between a 260gr Accubond at 2550 or a 300gr at 2600. The shoulder sure does, mostly in the carrying a 6lb rifle instead of a 9-10lb aspect.

Custom round of your own creation. Cool or what!

Wow

Beautiful country too! I want to go hunting with you!

Neat rifle. What CEbs are you shooting there?

Thanks for the kind words and that’s the 235gr ER Raptor there

This is the .30-06 fired to form a case deal I mentioned. For academic interest the .30-06 bullet leaves the .375 bore at 600fps.

And the test mule rifle, was a .30-06 Type A Oberndorf sporting rifle with a sewer pipe bore. Rebored and chambered to .375 Kemano, I’ll likely do a stainless Model 70 one next.

I have to ask, what’s the advantage over a hot loaded 9,3x62?

Frankly nothing revolutionary, it’s just a small incremental improvement over the 9.3x62. For me personally I prefer .375s and find there there more readily available bullets locally for it than 9.3, and it’s easier to load modern bullets to mag length than in the 9.3x62. I really like the 9.3x62 as well, and wanted its performance plus a hundred FPS with a .375 bore. Already load for the H&H, 9.5x57, and .375 Flanged Mag.

On the seating, it’ll seat the pointy monos (CEBs, TTSXs, GMXs) and conventional (Accubonds etc) in a .30-06 mag without intruding into the case and keep you close to the lands, which I couldn’t do in my 202 9.3x62 with the pointy 250s.

You always have the most interesting projects and country to try them out in.

I'm far from an expert but wouldn't starting with a 9.3x64 case necked up to 9.5 do the same thing plus a little more have been simpler?

Either way it looks like a fun project.

Very nice. I have only taken two of my own wildcats (.395 Tatanka and .500 Mbogo) to proper headstamp brass (mine by QualCart), as you have done here.
Who makes the .375 Kemano brass?

It brings a sense of accomplishment, eh? Doing good is its own reward.
When you get around to the M70 with stainless barrel,
here is a basic recipe for H&H-length Pre-'64 M70 Featherweight:



Since the Pre-'64 M70 H&H action is just a .30-06-length action opened up at the factory,
the Classic/FN H&H-length action is longer and a few ounces heavier.

My .458 WIN LongCOL featherweight will be a little under 7 pounds and kick a bit,
An African rear sight might get it up to 7 pounds.

Rip ...

quote:

Originally posted by Cougarz:
You always have the most interesting projects and country to try them out in.

I'm far from an expert but wouldn't starting with a 9.3x64 case necked up to 9.5 do the same thing plus a little more have been simpler?

Either way it looks like a fun project.

We live in a great part of the world eh, the PNW. The x64 case has the same issue as the x62 and .375 Whelen / .30-06 case, can’t seat modern bullets out and close to the lands. My pet project here does the 6.5 Creedmoor thing, brings back the case a smidge and allows proper seating depths in the mag for modern / higher BC bullets.

quote:

Originally posted by RIP:
Very nice. I have only taken two of my own wildcats (.395 Tatanka and .500 Mbogo) to proper headstamp brass (mine by QualCart), as you have done here.
Who makes the .375 Kemano brass?

It brings a sense of accomplishment, eh? Doing good is its own reward.
When you get around to the M70 with stainless barrel,
here is a basic recipe for H&H-length Pre-'64 M70 Featherweight:



Since the Pre-'64 M70 H&H action is just a .30-06-length action opened up at the factory,
the Classic/FN H&H-length action is longer and a few ounces heavier.

My .458 WIN LongCOL featherweight will be a little under 7 pounds and kick a bit,
An African rear sight might get it up to 7 pounds.

Rip ...

Doing my own brass actually, had a quote from Qual-Cart I couldn’t quick come to terms with. The WC stands for my little one man shop, Wild Coast. That’s exactly the idea on the Winchester, I like it.

Angus,
Well, you have gone the extra mile on this one.
Jolly good show!
You certainly do a great job.



Got your own bunter and some blank basic brass eh?
Who made that bunter?
For a pretty penny too?
What kind of press do you use to headstamp the brass?
Thanks for sharing.

Rip ...

Worked with a shop I know that does stamps they did it as a one off for me, they didn’t know what a bunter was but were willing to give a circular stamp with a pilot a try. I’m just hammer striking them right now, which is why it’s a tad uneven. Putting a the case on a large punch / rod with a base turned to match the inside of the case head for support, then strike the bunter with a 5lb hammer gently on the anvil. I’ll probably make a tube setup that holds the case and has the support rod built in, and use the hydraulic press to get more even stampings down the road. Will try overwriting existing headstamps too, to negate the need for basic brass.

quote:

Originally posted by PWS:
I have to ask, what’s the advantage over a hot loaded 9,3x62?

Nice cartridge, but I have to ask too, if you wanted a cartridge in standard Mauser action, did you consider the 404 Jeffery? Seems like a 400g A-Frame or Woodleigh softpoint at 2150 fps would do the job.

I like impacts of 2400fps or above for bears personally, and wanted a cartridge that could best 2500fps at the muzzle. Also would be a pretty challenging mountain goat guiding cartridge unfortunately, for all its history. The .404 has never found a home in my cabinet as I find the .375 H&H a better all around chambering for my purposes. And the purpose of this rifle was to be light and fit lots in the magazine, the .404 goes very much the opposite way. Though, I love that case, it’s just not for this rifle.

Thanks, once again nice cartridge and rifle

I am impressed.

A different approach might be to take a 375 Ruger Guide Gun and lighten it up.

Swift loads a 300 gr SAF at about 2500 MV.

With the factory brake, mine is a joy to shoot.

BH63

Have a cabinet of .375 H&H / Flanged Mag, while I appreciate the .375 Ruger and the biggest bear I’ve guided fell to it, I couldn’t stomach the hindrance on magazine capacity for this lightweight walking rifle. Didn’t need .375 H&H / Ruger range case capacity I found, so whittled down to what I did want and gained two in the mag. Again don’t think it revolutionises anything, but it’s a purpose built recipe for what I personally do.

Angus,
Thanks for the headstamp explanation.
For the heck of it, don't sell the 404 Jeffery short.
The Chadwick Ram, greatest North Amerian trophy ever, a Stone Sheep from BC, was wounded by Mr. Chadwick with a 404 Jeffery and 300-grain bullet at about 2600 fps.
The PH/guide finished it off with a .30-06.
Mr. Chadwick was elderly and not fit for the followup.
Maybe Mr. Chadwick was breathing too hard to hold steady on the sheep?

Rip ..

quote:

Originally posted by Angus Morrison:

quote:

Originally posted by Cougarz:
You always have the most interesting projects and country to try them out in.

I'm far from an expert but wouldn't starting with a 9.3x64 case necked up to 9.5 do the same thing plus a little more have been simpler?

Either way it looks like a fun project.

We live in a great part of the world eh, the PNW. The x64 case has the same issue as the x62 and .375 Whelen / .30-06 case, can’t seat modern bullets out and close to the lands. My pet project here does the 6.5 Creedmoor thing, brings back the case a smidge and allows proper seating depths in the mag for modern / higher BC bullets.

Gotcha, that makes sense.

And yes the PNW is a very great place.

Angus,
And I thought I had it bad .
Thanks

Well for me; I am glad you both “have it bad.” The rest of us have learned much from your “drug” trials.
Best regards.

Kind of like a 376 Steyr, but without single source brass and odd rim diameter to deal with. Great idea, I like this little cartridge!

quote:

Originally posted by Angus Morrison:
I should note, for forming brass I adopted an odd technique- fire a standard .30-06 in the chamber and you get a .375 Kemano case with a 1/4" of extra neck. Trim that off, load and go. I set the headspace for a slight crush on a standard .30-06 to allow that.

-Angus

Nice round .. and an interesting tale on this one .. i did about the same story, with 350 rem to 375 --

on the fire and trim .. i do just about exactly the same thing when making the AccRel rounds

quote:

Originally posted by 458Win:
Angus,
And I thought I had it bad .
Thanks

Gets worse Phil think I’ll have to attempt a scratch built new action design in the coming years, it’s been eating at me.

quote:

Originally posted by Angus Morrison:
Have a cabinet of .375 H&H / Flanged Mag, while I appreciate the .375 Ruger and the biggest bear I’ve guided fell to it, I couldn’t stomach the hindrance on magazine capacity for this lightweight walking rifle. Didn’t need .375 H&H / Ruger range case capacity I found, so whittled down to what I did want and gained two in the mag. Again don’t think it revolutionises anything, but it’s a purpose built recipe for what I personally do.

No doubt, there is a tremendous satisfaction in creating and hunting with a one off.

Thanks for sharing.

BH63

I'm gonna have to rip off the case forming thing.
I have a very similar cartridge in 30 caliber, your method might have just saved me some trouble, errr time.

to speed up this "overlong" case approach, i made a tailstock for the harbor freight mini chopsaw .. just an L shape with a screw for setting length .. works great for lopping off, way easier than lathe or hacksaw

I use a Rigid tubing cutter just use the end of the .375 mouth where it goes down to bore size as the mark, about four turns put it in a trim die and done. All in using the fire a standard .30-06 method I might have thirty seconds into making a case if I take a sip of coffee in between operations. More than just running a .35 Whelen case into a .375-06 die (have that as well), but not so much more as to be a notable pain in the arse or worry one about losing brass.

Harbor Freight mini chopsaw, Rigid tubing cutter ...
I am taking notes, handy for converting .458 Lott brass to .458 WIN.
Wondering if a Harbor Freight mini arbor press could be used to headstamp brass.
One-ton, 2-ton ... what would be enough?
Might be a more easily controlled and repeatable in result than a hammer blow.
Maybe even a caveman could be trained to do it.
No special skill and learning of finesse with mallet, but would it be any better in result?

Rip ...