7mm Imperial Magnum

Moon

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Not a real popular cartridge and even less information. I have tried unsuccessfully to get new brass for this baby and my Nick Harvey reloading manual has been on backorder since August of last year.

Has anyone tried fire-forming 7mm Ultra Mag brass for this cartridge. I believe there is only a couple of degrees difference on the neck, but I don't want to blow myself up in the middle of an experiment gone bad! Thanks in advance, Mike.
 
I had a .338 imperial a few years back,traded with Rembo.Talk to him and try to trace the rifle down,or more importantly the loading data.Nass shooting systems phone number is in there,they are still making or carring the brass as I talked to the man himself Aubry White. I will comment the imperial brass is very soft,about 3 loadings and thats it,it flows like putty.Best of luck!!!!!!
Bulletsmith
 
Rembo sold the rifle to a guy in SK who needed it for charging gophers. I got to shoot it (kicked worse then my 338 Lapua) and reload some ammo for it before it went away, basically it is a 338-300 RUM. The base dimensions may or may not work, depending on how tight your extractor is set up, I've seen them go both ways. Just start with starting 7mm RUM loads in your rifle, that should be safe enough, and see how they feed and extract. - dan
 
Thanks a lot for the info guys. Stubblejumper, even if you could spare 50 rounds, I would be grateful. When I bought the rifle, it came with about 100 rounds of loaded ammunition, but I am pretty certain they have been loaded at least once. The gentleman I purchased the rifle from was supposed to get me 250 new brass, but either he forgot or couldn't get them. I would appreciate any help in regard to load info. I did get some help from the board last year, and on someone's advice ordered Nick Harvey's Practical Reloading Manual.

I will continue to research and perhaps try some 7mm RUM casings... of course you are all indemnified from any potential liabilities... LOL.

It's a beautiful looking rifle, and I sure would like to put it to good use. I have never measured or loaded powder by the tablespoon before! Thanks again, Mike
 
I kept one of the loaded rounds from the 338 Imperial...it's base is rebated the same as an Ultra Mag..this one actually measures .528" ....headstamp is 338 Imperial Magnum...

I hooked Dan into shooting it.....told him it was a pussy cat....he didn't keep it long:) :D....I never shot it:D ..
 
338 Imperial Magnum Brass

When I bought my 300 Ultramag there was neither any loaded rounds nor brass available. I bought 100 rounds of 338 Imperial Magnum brass from Avery White, full length sized it in my Hornady 300 ultramag die, trimmed and turned down the necks. They worked fine but the case capacity is a bit less than the corresponding Remington brass. My powder work-up for the Imperial Magnum brass is different than for the Remington brass.

Avery is usually at the Kamloops gun show (this coming week-end). PM me if you would like me to make an inquiry for you.

Peter
 
Moon-I just checked my supply and I can spare 100 rounds with no problems.If you send me a PM we can work out the details and get each others addresses.
 
Thanks for all the help lads. This was far less painless than I expected and I hope that I can return the favors one day. I PM'd Stubblejumper, so I should be good to go on the brass for a bit, but thanks for your offer Peter.

I had read that the accuracy on these guns is outstanding, so I am interested in working up a few loads. If I remember correctly, Aubrey won a prestigious long-range shooting contest somewhere in Texas using his 7mm Imperial Mag. I would like to make a good, accurate hunting load and am still trying to decide between a 150 and 160 grain bullet. Any thoughts? I am leaning towards the Nosler Partition and/or Hornady Interbond but also picked up a box of the new Barnes Triple Shocks in 160 hearing they had reduced fouling problems and improved accuracy. Main game for this rifle would be Elk and Mule Deer. Thanks again, Mike
 
I have been using my 7mmimp mag as a longer range practise rifle and it seems to shoot 140 to 160gr bullets quite accurately.However for hunting,I would try the 140gr tsx and if it shoots well in your gun,you certainly don't need a heavier bullet.I have taken several elk and moose with 140gr premium bullets and the performance was very good.
 
Thanks a million guys!

What a site! Two days ago I posted looking for some information on a very obscure cartridge. In that time I have located brass, obtained reloading information and gotten some very good advice based on experience. Thanks a bunch guys, it's like Christmas in March! Very best regards, Mike
 
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