.416 application, 300 RUM vs. .375 RUM brass?

nw07heavy

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Mar 3, 2012
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I have a question for those of you with .416-300 RUM, .416-375 RUM, or .416 UltraCat experience. Looking at the SAAMI drawings for the .300 RUM and .375 RUM cartridges I see that the outside case dimensions are identical, and the 30 degree shoulder beginning at 2.3873" is the same for both cases, which would indicate that either case would be suitable for loading a .416 bullet into standard RUM cases, once the length reaches 2.4540 and the neck begins. My question is whether they would reload and function equally well. I understand the .375 RUM cases would be less trouble than the .300 RUM to neck up to .416 due to needing less size increase. Is there something I am missing in regards to this brass, possibly neck thickness? I also noticed that reloading dies come in designations of .416-300 RUM, .416-375 RUM, and .416 UltraCat (all appear to have the standard RUM dimensions) and wondering what the functional differences are between these designations, and subsequent selection of reloading dies. Thanks for any insight you can provide.
 
I think it may be that the neck would get thinner on the 300RUM case.
Going from .308" to .416" is a very big step up.
I don't see how the reamers would be any different, the case dimensions to the shoulder datum are the same for either.

Cheers.
 
They both work but the 375RUM would be one pass over a expander ball from a 416 die where as a 300 would be at least 3 steps and the potential for split necks goes up greatly if the brass isnt annealed. Plus, as was mention, the case necks will thin out a good deal starting with 300 brass.
 
Factor in one more variable...375 RUM brass has been incredibly hard to find now for many years. Bertram makes it on a whim occasionally. I have a 375 RUM and a 375 RUM wildcat. Love to shoot them, but always have to be very cognizant of picking up my brass after I make my shot in the field.
 
Factor in one more variable...375 RUM brass has been incredibly hard to find now for many years. Bertram makes it on a whim occasionally. I have a 375 RUM and a 375 RUM wildcat. Love to shoot them, but always have to be very cognizant of picking up my brass after I make my shot in the field.
I just bought 12 boxes at Graff & Sons $26.50 box
 
If its that hard to get I just bought another 10- boxes for a total of 22 it was $26.09 a box if you bought 10, $1.30 a round is a great price. Thanks for the heads up
 
I just bought 12 boxes at Graff & Sons $26.50 box.

Thanks for this tip. I've not checked back on this thread since several months after posting in 2015. No one had any feedback to give. I do appreciate your information and am ordering brass from Graff & Sons.
 
RCC Brass says he can make anything. He even makes brass for both of my mildcats. What a shock to discover that he makes brass for the only two rifles in the world that would use it...

www.rccbrass.com
 
I just bought 12 boxes at Graff & Sons $26.50 box.

Thanks for this tip. I've not checked back on this thread since several months after posting in 2015. No one had any feedback to give. I do appreciate your information and am ordering brass from Graff & Sons.
That is the most amazing rifle I have ever had built. 350 gr Barnes TTSX at 2,800fps drops 41" at 500 yds and shoots 1/4 MOA. MBM Superbeast brake and I can shoot it one handed. Shot a 2" group at 865 yards. Got PTG 3.850" detachable mags and bottom metal so I can load .010" off the lands. Started with a Rem 700 Long Range in 300 RUM so length and bolt face were right. Wilson 26" barrel plus brake. Rifle came with Bell Carlson full aluminum bed stock. It will be Nilgai medicine in January.
 
Here is my post on a 416 that uses a 375 RUM case. that has lost of information on the round. Even though it is a dangerous game rifle It has the distinction of shooting my best group ever. (.034)

https://www.longrangehunting.com/threads/416-buff.21003/#post-143160

Easy to size and load for and likes a wide range of bullets from 325 to 400 grains.

J E CUSTOM
I built that rifle because of your post. It is a long range capable safari/dangerous game rifle. At 500 yards shooting steel plates, you would hit the same splat on the plate and almost rip it off the hangers. Thank You JE Custom for your post.
 
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