450 B&M EX

[1972RedNeck]

Anyone have experience with the 450 B&M EX? Basically a RUM case shortened to 2.5" and necked to .458. Supposedly a slight step above a 458 Lott with a standard .534 bolt face and without a magnum length action.

Seems like a good cartridge. Thoughts?

 

[ldmay375]

@michael458 can probably shed some light on that one.

 

[AZDAVE]

Have both a 458 standard B&M and a 458 B&M super short.

The standard is RUM brass cut down to 2.240. Fits in the WSM action. It runs with the WIN MAG level of ballistics but does it in a 18 to 20 in barrel.

 

[1972RedNeck]

Have both a 458 standard B&M and a 458 B&M super short.

The standard is RUM brass cut down to 2.240. Fits in the WSM action. It runs with the WIN MAG level of ballistics but does it in a 18 to 20 in barrel.

Yeah, I'm interested in the EX version which uses a 2.5" case length. Just not much info out there for it...

 

[AZDAVE]

That you will have to talk to @michael458 about I have no experience with that version.

 

[michael458]

Anyone have experience with the 450 B&M EX? Basically a RUM case shortened to 2.5" and necked to .458. Supposedly a slight step above a 458 Lott with a standard .534 bolt face and without a magnum length action.

Seems like a good cartridge. Thoughts?

Yes, there is One Single individual on the planet with 458 B&M EX "EXperience", me. Problem is, this is a ONE OFF personal experiment type cartridge/rifle. It is not a regular member of the B&M Family with dies and other things available. There is only one rifle built, which of course I have. It is a good cartridge and rifle, at 20 inches it is equal to and can surpass 458 Lott at 24 inches. The big advantage, and its purpose in life, was/is to be able to use full nose projection CEB Raptors with a Talon Tip, and run through the magazine, hence the reason for 2.5 inch RUM and full length Winchester RUM action. The Talon Tips gain you around 125 fps at 50 yd impact velocity, which if you can imagine is a 125 fps increase in velocity, without any added pressure.

Sorry, but dies and other requirements are just not available, I never considered it part of the regular public family, more of an personal experiment on my part. Same with the 2.5 inch 500 B&M as well. Those two are specialty projects of mine. As it turns out, both are favorites of mine, especially the 500.

 

[michael458]

Let me show you the 458 B&M EX............. Now you ask what does the EX stand For? Well, could be a lot of things, it could be "Express", kinda catchy. Or it could just be "Extra", more bang for the 458 caliber buck. Maybe "Experimental"........... Or maybe just some Bull S**t I made up so I can tell it from the regular 458 B&M.... HEH.......

This is a lower pressure load at 56000 PSI. In other tests I have run the 450#13 to 2450 fps at 62000 PSI, and the cartridge can go to 65000 PSI without issue, but I saw no reason to do so. If I were hunting the rifle, the 2375 fps and 56000 PSI would be my choice and more than enough. It is not, and should not always be about getting the highest velocity possible........... we are not in a race, we are looking for peak terminal performance, without paying the highest price..........

 

[RLL]

Love my 458 B&M, Thanks Michael!

I was building 2 - 458’s at the time and was interested in the “Extra” chambering as well but built a Lott to the same rifle specs I was looking for in the B&M. No problems in ballistic and terminal performance with the same CEB’s.

 

[michael458]

but built a Lott to the same rifle specs I was looking for in the B&M. No problems in ballistic and terminal performance with the same CEB’s.

Yes, I still have a couple of 458 Lotts on hand as well, and my Accountant is a devoted 458 Lott and buffalo hunting fan as well. I load for him, using the same 450 #13s at 2360 fps in his Lotts, these are too lower pressure loads, and he has been successful on several buffalo using the 420 Raptors, follow up with the 450 Solids, and so far two big elephant bulls with the 450s...........