Imperial Magnum Rifles and Cartridges

Doug

Doug

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I was reading a 1995 issue of The Compete Rifleman and saw an ad for these rifles and cartridges. If I can figure out how to scan and post the quarter-page ad, I think others might also find it to be of interest. The ad has a dimensional drawing of a .360 Imperial Magnum case, but indicates the mouth diameter to be .388 Inches. I assume this has to be a typo and it should be .358. They list 7 mm, .300, .311, .338 and .360 Imperial Magnum. According to the ad they used barreled actions from SAKO and stocks from McMillan and Pacific Research USA.

I do not recall hearing of these before. A Google search doesn't provide much illumination, and a search here yielded one recent post in this forum, but this has just whetted my appetite.

So, there are a lot of knowledgeable people on here, and I am all ears for anything you can tell me about these cartridges and these rifles. (I think I "need" one...)

Doug
 
Banished was one of them. Don't remember, but I think he's Ono. Also believe he recently died..??? Their were two of them. Basically Remington turned these into the Remington ultra mag family.

Today the trend is light recoiling calibers in a fast twist rifle with tight match grade chambers. The ultra mags are a different idea, largest case possible, 100+ grains of powder and make it go real fast. Here today....gone tomorrow barrel life, especially if you shoot long fast groups. I have a 300 and 375 rum, both require muzzle brakes, and I wouldn't go with a ultralight rifle. Have heard 7mm rum is a real barrel burner.....like 6-800 rds.
 
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Aubrey White was the inventor and put a lot of money into it... he was negotiating with Sako to produce brass and the line of cartridges and instead they dropped him and came out with the big Lapua round. Then Aubrey spent a lot of money trying to get quality brass made in South America. It's a great line of cartridges if you want big performance.
 
guntech said:
Aubrey White was the inventor and put a lot of money into it... he was negotiating with Sako to produce brass and the line of cartridges and instead they dropped him and came out with the big Lapua round. Then Aubrey spent a lot of money trying to get quality brass made in South America. It's a great line of cartridges if you want big performance.
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Agree. The 338 version will certainly do anything a 338 Lapua will, and the 300 was a RUM before Remington coined the term. - dan
 
guntech said:
Aubrey White was the inventor and put a lot of money into it... he was negotiating with Sako to produce brass and the line of cartridges and instead they dropped him and came out with the big Lapua round. Then Aubrey spent a lot of money trying to get quality brass made in South America. It's a great line of cartridges if you want big performance.
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Thanks!

And I just read your sig line - I hope you have a long, happy and healthy retirement!

Doug
 
Sad to hear he died if thats the case.

I reached out to him this time last year for some dummies rounds.

Wanted to do a .360 for myself but got hung up on needing a LH rifle and it never worked out.

I knew I should have loaded up on brass, too. Damn.
 
Gr33zi3 said:
Sad to hear he died if thats the case.

I reached out to him this time last year for some dummies rounds.

Wanted to do a .360 for myself but got hung up on needing a LH rifle and it never worked out.

I knew I should have loaded up on brass, too. Damn.
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The brass was poor quality, so no loss there. Better off to use ultra mag brass and neck it accordingly. This was suggested to me by Aubrey White. The 360 is a pretty sweet. I bought one from Aubrey. He gave me one of the original brochures with the rifle, its kind of cool. The Imperial magnums are the original ultra Mag. When the Imperial magnum corp. went belly up Remington bought the rights to it changed the shoulder angle from 28 to 30 degrees and called it the ultra mag. Got to see the paper work from the deal, Was pretty cool to talk to Aubrey White and get all the history on the company when I bought his rifle. He said the the poor quality brass that Ono contracted out in south america is what made them go belly up. They got false quality control reports. The brass was extreamly soft and primer pockets are loose after one firing. The Imperial Magnum cartridges are great rounds, If you can find a rifle or want to build something different.
 
There is lots of info on the history in this thread...
https://www.africahunting.com/thread...ensions.61767/
imperial magnum corporation ~--•
the history of imperial magnum cartridges by aubrey g. White, january, 2003

the genesis of the modem commercial beltless magnums is the story of the
imperial magnum cartridge development.
In 1989 gus rios, president of royal canadian cartridge & munitions inc.
(rccm) of north vancouver, b.c., purchased the "imperial" and related
trademarks from valcartier industries ltd. (ivi). These trademarks had
been purchased by ivi from the original trademark holders, canadian
industries ltd. (cil). Cil had been producing ammunition continuously in
canada since about 1919.
Rccm intended to reintroduce a full line of imperial brand ammunition to
the international market place. To attract attention to the imperial
trademark they wished to develop a new, high performance, magnum rifle
cartridge. Rios had developed a cartridge he called the "imperial .311
canadian magnum". This cartridge was the belted .338 winchester case
necked down to .311 caliber but did not provide the attention getting
performance he was looking for. Aubrey white of osoyoos, b.c.
Suggested that rccm develop a full line of magnum cartridges, from 7mm
to .358, all based on the non-belted .404 jeffery case. It was anticipated
that full length cartridges based on this case would be capable of out
performing all existing belted magnums in their class. A .404 beltless case
also provided additional benefits in that it allowed the maximum powder
capacity possible in standard magnum rifle actions, ensured more accurate
head spacing and improved feeding through rifle magazines. A non-beltled
case is also less costly to produce than one with a belt.
Even though white suggested other common calibers be given priority,
rios wanted the .311 caliber for a unique canadian identity. White's
company, north american shooting systems (nass) designed and formed
the cases, assembled some ammunition and a rifle for the .311.


The first test firing occurred on october 31st, 1989. By the next day,
november 1st, load development resulted in record results. 180 gr. Sierra
.311 bullets were consistently chronographed at 3,,435 fps within acceptable
pressure limits, faster than any other in history. That performance was
achieved with hand formed rws .404 jeffery cases, 89.0 grains of rl22
powder and #215 federal primers in a 26" maclennan barrel. It is still one
of the very best loads for the .31l
in 1990 nass was licensed exclusively by rccm to use the imperial
trademark to produce rifles. The cartridges were named "imperial
magnum". Rccm was to produce cartridge cases and eventually load
ammunition. Kimber of oregon built one prototype rifle for nass
chambered for the .360 imperial. Serial number of this rifle is nass-ooo1.
Nass intended to further contract kimber to manufacture production rifles
chambered for all the imperial magnums. Before production could begin,
kimber went into receivership. Nass continued cartridge development but
marketing plans went on hold until 1991.
To gauge dealer interest, rccm publicly displayed the .311 magnum
cartridges and a rifle for the first time in january of 1991 at the dallas tx
"shot show". Enthusiastic dealer response convinced rccm to formally
announce its intention to produce a full line of imperial magnum rifles and
cartridges. Negotiations between rccm and aubrey white resulted in
nass developing the 7mm, .300, .311, .338 and .360 imperial magnum
cartridges. Rccm and aubrey white formed an rccm subsidiary
company call the "imperial magnum corporation" (imc). !mc was
licensed to use the imperial trademark to market imperial magnum
cartridge cases and rifles. In 1993 sako of finland was subcontracted to
produce barreled actions which were fitted with mcmillan or pacific
research stocks by !mc. Sako manufactured one prototype and one
production run of 85 imperial magnum barreled actions .

The following are the sako production figures of imperial magnum rifles;
7mm imperial magnum serial no's im 000001 to im 000025
.300 imperial magnum serial no's im 100001 to im 100015
.311 imperial magnum serial no's im 200001 to im 200012
.338 imperial magnum serial no's im 300001 to im 300013
.360 imperial magnum serial no's im 400001 to im 400020
.360 imperial magnum serial no. Im 000000 (prototype)
"cavim" of venezuela manufactured the cartridge cases using usa brass
cups from olin. Imc never produced loaded ammunition. Customers
loaded their own using imc cases, rcbs loading dies and loading data
developed and supplied by imc.
Imc began marketing rifles and cartridge cases in 1993. Unfortunately a
combination of subcontractor problems with the cartridge cases and
financial difficulties experienced by a major shareholder forced imc to
cease operations in 1995. Customers were very pleased with both cartridge
performance and rifles. Some complaints were received concerning soft
brass cartridge cases but no rifle was ever returned for any reason.
Many "wildcat" cartridges have been hand formed from .404 brass over the
years but the imperial magnums were the first with commercial cartridge
cases and rifles. The large capacity beltless design has been an
overwhelming commercial success but unfortunately not for the originators.
Winchester and remington have introduced at least eight new beltless
magnums since !mc stopped production. Dakota arms cartridges use only
the beltless design and john lazzeroni used the concept to develop his full
line of rifles and cartridges. A total of thirty new non-belted magnum
cartridges have been introduced to the market place. Only weatherby
continues to develop new cartridges with the outdated belted case.
Aubrey g. White
box 306, osoyoos, b.c. Voh 1vo
phone 250-495-3581 fax 250-495-3131
e-mail ritle@otvcablelan.net
i

in canada: Ro. Box 306, osoyoos, tic. Voh ivo
in the usa: Eo. Box 249, oroville, wa. 98844
telephone (604) 495-3131 fax (604) 495-2816
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I recently acquired a pretty much new 338 Imperial. It came with dies and all the original paperwork and literature from Aubrey. It also came 100+ Pieces of each the Imperial marked brass and the Canadian marked brass. I also received the original box as well.

Very interesting cartridge and company.
 
I’ve got a 338 Imp Mag, had it for several years. Never shoot it anymore, but I got it to shoot.5” groups at around 2950 fps with a 250gr Hornady. Always wanted to play with the slow powders such as RL26, 33, H1000, but I don’t have any load data for those powders. Need someone that has Quickload hint hint….
 
aardvaark said:
I’ve got a 338 Imp Mag, had it for several years. Never shoot it anymore, but I got it to shoot.5” groups at around 2950 fps with a 250gr Hornady. Always wanted to play with the slow powders such as RL26, 33, H1000, but I don’t have any load data for those powders. Need someone that has Quickload hint hint….
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Spooking around the Internet, it seems to me that somebody said that the .338 Imp was basically the same as .340 Wby. Might that be something to look at for data? If your old data matches .340 Wby....
 
Doug said:
Spooking around the Internet, it seems to me that somebody said that the .338 Imp was basically the same as .340 Wby. Might that be something to look at for data? If your old data matches .340 Wby....
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Very similar velocity wise. As for new data, use 338 edge data from berger. They are both the same cartridge other then shoulder angle only 2 degrees different.
 
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