I believe that was the one I owned.
I still have a loaded round with the Imperial Magnum head stamp.
It didn't kick much at all, did it Dan?...
360 Imperial Magnum
- Thread starter ChewyChewbacca
- Start date
I believe that was the one I owned.
I still have a loaded round with the Imperial Magnum head stamp.
It didn't kick much at all, did it Dan?...
- Location
- Port Edward BC
How is the 375 with the brake. The biggest caliber I’ve ever shot is the 9.3 x 62 and didn’t find the recoil bad at all. Mind you the powder charge is just about twice as much so a lot more horse power behind the same weight of bullet. Was wondering if I shouldn’t get a 375 RUM with a brake and see before I go down the path of getting an Imperial 360 built. There is a couple for sale that aren’t to expensive and if it’s not to bad then that way I would have a donor action and stock.
https://loaddata.com/Cartridge/360-Imperial-Magnum-/6502
There was a member here named Banished...
I do not know if he still posts though.
Rob
There was a member here named Banished...
I do not know if he still posts though.
Rob
I doubt you'll find any surplus brass for this cartridge. Should be able to make brass from 338 or 375 RUM brass though. Load data is out there but not much. As mentioned, I did some load development for Rembo's 338 Imperial. You could use 338 RUM data for similar bullet weights though, the larger bore should keep pressures within a safe range. These are boomers. Be prepared for substantial recoil, unless you have a very efficient muzzle brake. - dan
Last edited:
Hardly at all Rick.I believe that was the one I owned.
I still have a loaded round with the Imperial Magnum head stamp.
It didn't kick much at all, did it Dan?...
- dan
Aubrey White from Osoyoos BC - Really a Nice fellow but deceased now
- HE put a LOT of money into the Imperial line of cartridges !
Quarterman2
New member
- Location
- In the mountains
I just sold mine a month ago, It is basically a 358 RUM, 2 degree difference in shoulder angle. To make brass, simply neck down 375 RUM brass and trim off .030". This is what the RUM cartridges were made out of. When the Imperial magnum corperation went out of business Remington bought the rights to the imperial magnum cartridges, they changed the shoulder angle 2 degrees and called them the Remington ultra magnums. I got this info from Aubrey White and he showed me the paper work from when Remington bought the rights to the Imperial magnums. The original rifles were made from sako trgs-995 actions. I had Aubrey Whites personal 360 imperial magnum. Great cartridge, it pushes a 250 grain bullet about 3050 fps and a 225 grain a bit over 3100 fps
Quarterman2
New member
- Location
- In the mountains
Banished was Aubrey White, I was told he has passed away.
Quarterman2
New member
- Location
- In the mountains
I’ve got a 338 Imp Mag. Bought it from Aubrey at a gun show in Calgary many years ago. Along with a set of dies. In a Sako AV. Don’t shoot it much cuz frankly it’s way more gun than necessary around here. It came with a brake, first year I shot a deer with it, my ears rang for 2 days after. Took the brake off and then it kicked me around the block. Epoxied a few pounds of lead shot into the forend and the buttstock, and now it shoots beautifully, groups well under an inch. But it’s relegated to bench shooting only.
I bought 3 boxes of Imp Mag headstamped brass, still got them in original boxes, but from new the primer pockets are loose, Aubrey told me he got a bunch custom made for him and it arrived with loose pockets. But really easy to make from 375 RUM brass, neck those down, the headspace fits tight enough to fireform, the only difference is the shoulder angle.
Only ever shot it with Hornady SP 250gr and Barnes 250. Both shot really well but the Barnes are too long, by the time they get to 300 yds they keyhole. IMR 4831 powder is what’s recommended and all I ever used.
Case on R is 270W, for comparison.
Attachments
Last edited:
I am sorry to hear Aubrey has passed away; I used to stop and visit with him on my trips back and forth through there. He was a real gentleman who developed his rifle company after retiring from the Force.
If my memory is correct, he developed his proprietary chamberings with Knobby Uno, a benchrest competitor and gun builder. Knobby at the very least built his original Imperial rifles. And he did get screwed around by one of the big names he approached with his Imperial line of chamberings. I'm not positive I remember Aubrey's version now so many years later, but I think whoever he took his cartridge chamber dimensions to ended up just changing the dimensions slightly and coming out with their own line of 416 Rigby based cartridges. Dakota perhaps?
Aubrey wasn't even close to being the first person to design a cartridge case on the 404 Rigby. Wildcatters in the late 1940's and 1950s created numerous variations on that chambering, generally by necking it down and shorting the case most of the time. Aubrey refined that for his family of Imperial Magnum cartridges.
I fired one of those 360's at Aubrey's range one day while ordering a custom rifle from him for my father as Dad's retirement approached. At the time I didn't think the recoil was all that bad; I was hunting up in grumbly bear country at the time with one of Husqvarna's 1960's "Husky" featherweight rifles in .358 Norma Magnum with 250 grain Bitterroot bullets up the spout so that was my measuring yardstick.
But that was about 40 years ago, and I was more beefy shoulder and arm muscle than the different skin and bones as I am now approaching 71. These days the .358 Norma Magnum feels like it's kicking me from out under my hat, and my 30 Newton rebarreled Husqvarna Husky feels like it is almost doing the same.
That 360 will be burning more powder than .358 Norma Mag loads in that bigger case and be capable of greater velocity. Despite the rifle being a few pounds being heavier than my Husqvarna, it is going to generate more recoil than my .358 Norma Magnum.
Ultimately we had Aubrey build Dad one of his Imperial rifles on a Sako action chambered in .308 Norma Magnum. It has been extremely accurate since we got it and my brother now has it and does his moose hunting around and north of Quesnel with it. I doubt Aubrey would have allowed a rifle out of his business that DIDN'T group extremely well.
I don't like dragon calls installed on rifle barrels myself although others have the opposite opinion on muzzle brakes, so that is an option.
You can split the difference and have the barrel magnaported. Noise dBA's aren't noticeably louder with magnaporting unlike when they have muzzle breaks.
There is also no law I am aware of that says you have to load that 360 up to maximum velocities. Giving up a few hundred fps of velocity will be easier on you and won't decrease it's effectiveness on game.
I load bulk swaged lead .358 pistol bullets in my .358 Norma (and 35 Whelen and .358 Winchester) after powder coating them with just enough powder to get them to around 950 fps. Think of it as heavying up for those big bull gophers lurking in the grass or on the other side of a dirt mound.
Then you can shoot that rifle all summer and I doubt you'll ever put any wear on the rifle or yourself doing that.
If my memory is correct, he developed his proprietary chamberings with Knobby Uno, a benchrest competitor and gun builder. Knobby at the very least built his original Imperial rifles. And he did get screwed around by one of the big names he approached with his Imperial line of chamberings. I'm not positive I remember Aubrey's version now so many years later, but I think whoever he took his cartridge chamber dimensions to ended up just changing the dimensions slightly and coming out with their own line of 416 Rigby based cartridges. Dakota perhaps?
Aubrey wasn't even close to being the first person to design a cartridge case on the 404 Rigby. Wildcatters in the late 1940's and 1950s created numerous variations on that chambering, generally by necking it down and shorting the case most of the time. Aubrey refined that for his family of Imperial Magnum cartridges.
I fired one of those 360's at Aubrey's range one day while ordering a custom rifle from him for my father as Dad's retirement approached. At the time I didn't think the recoil was all that bad; I was hunting up in grumbly bear country at the time with one of Husqvarna's 1960's "Husky" featherweight rifles in .358 Norma Magnum with 250 grain Bitterroot bullets up the spout so that was my measuring yardstick.
But that was about 40 years ago, and I was more beefy shoulder and arm muscle than the different skin and bones as I am now approaching 71. These days the .358 Norma Magnum feels like it's kicking me from out under my hat, and my 30 Newton rebarreled Husqvarna Husky feels like it is almost doing the same.
That 360 will be burning more powder than .358 Norma Mag loads in that bigger case and be capable of greater velocity. Despite the rifle being a few pounds being heavier than my Husqvarna, it is going to generate more recoil than my .358 Norma Magnum.
Ultimately we had Aubrey build Dad one of his Imperial rifles on a Sako action chambered in .308 Norma Magnum. It has been extremely accurate since we got it and my brother now has it and does his moose hunting around and north of Quesnel with it. I doubt Aubrey would have allowed a rifle out of his business that DIDN'T group extremely well.
I don't like dragon calls installed on rifle barrels myself although others have the opposite opinion on muzzle brakes, so that is an option.
You can split the difference and have the barrel magnaported. Noise dBA's aren't noticeably louder with magnaporting unlike when they have muzzle breaks.
There is also no law I am aware of that says you have to load that 360 up to maximum velocities. Giving up a few hundred fps of velocity will be easier on you and won't decrease it's effectiveness on game.
I load bulk swaged lead .358 pistol bullets in my .358 Norma (and 35 Whelen and .358 Winchester) after powder coating them with just enough powder to get them to around 950 fps. Think of it as heavying up for those big bull gophers lurking in the grass or on the other side of a dirt mound.
Then you can shoot that rifle all summer and I doubt you'll ever put any wear on the rifle or yourself doing that.
