At the DSC convention I came across a gun maker that had produced I think eight rifles for an outfit in Zim and they were all chambered in the 550 magnum. I can't find this caliber listed in my 12th edition of "Cartridges of the World." The dummy round is quite large and to think that these rifles were only weighing I think he said something like 10.4 lbs. So, anyone know something about this big 550 magnum?

Neal Shirley and his 550 Magnum cartridge creation are well known to the oldtimers here.
Even Google will help, then a search here ...

https://www.google.com/?gws_rd...gnum+by+Neal+Shirley

Google leads first to this, the best place to start:

http://www.custombrassandbulle.../550caliberpage.html

" ... Besides, if you think big guns are fun, then the bigger they are the more fun they may be.

"They don’t come much bigger than the .550 Magnum developed by Raymond Neal Shirley. If you insist on tracing genealogy, it can be said that the parent bore of the .550 Magnum is the 55-100 Maynard of 1882 and its parent case is the .460 Weatherby Magnum of 1958, but the .550 is a very different cartridge from either of its ancestors and has capabilities important to the dangerous-game hunter which far exceed those and most every other sporting cartridge on the planet. A modest load launches a 700-grain, .550”-diameter bullet at 2150 fps, thereby delivering 7,200 foot-pounds of kinetic energy at the muzzle and a Taylor Knock Out Value of 118. Rifles in this power category developed over the last hundred years can be counted on the fingers of one hand. When velocity is increased to 2300 fps, muzzle energy goes up to 8,222 ft/lbs, which is the equal of the gigantic .600 Nitro Express in a vastly smaller package. The .550 is clearly designed not just to efficiently dispatch a dangerous and determined animal but to plain stop it in its tracks. Drop it right now. End the argument no matter how compelling the horned beast at the end of your muzzle may be ..."

"Easy Link" to this cartridge (copy and paste into emails, forums, etc.):
.550 Magnum - http://ammoguide.com/?catid=739


Sort of like a belted 28 Gauge from Hell 3-Inch that works very well in a Rigby-length bolt action rifle.


Now jeffeosso and Ed Hubel may discuss their wildcat variations on the .550-caliber cartridge:
See below.


Riflecrank Internationale Permanente
NRA Life Benefactor and Beneficiary
https://home.nra.org/

Wayne at AHR chambers rifles in the 550 Magnum, based on CZ 550 actions. That's probably who built them? Wayne knows his way around safari rifles, for sure.

quote:

Originally posted by RIP:

When velocity is increased to 2300 fps, muzzle energy goes up to 8,222 ft/lbs, which is the equal of the gigantic .600 Nitro Express in a vastly smaller package.

You can't get me drunk enough to fire that...I'd pass out first.

Here'a link to Wayne info on the 500 Magnum:

http://americanhuntingrifles.com/?page_id=33

There is also the 550 Gibbs aka 550 Jamison Magnum.

Basically a 505 Gibbs necked up to 550.

Mine weighs around 11 lbs without a scope.

My guess is the rifle you saw was chambered in Neal Shirley's excellent design.

Then there is the .600 overkill. 2400fps with a 900 gr bullet. -Rob

So,
The 550 magnum is a straightened 460 weatherby case, invented by Neal Shirely, our RNS here on AR. 700gr bullet about 2300 - its manageable in a 10.5# rifle, and you can do a search for it on facebook to find pics of a PH using it.

sure neat round. Neal and I then did the 550 express, which is a shorter version, designed to fit into standard length actions, and does 700gr at 2000 ish... and also manageable in a 10-11# rifle... in fact, in a hunting situation, a 9# might not be too savage.

quote:

Originally posted by Robgunbuilder:
Then there is the .600 overkill. 2400fps with a 900 gr bullet. -Rob

That has to be the best choice, the only choice with the 500 A2 at the smaller end. Then the 505 or 500 J for a full custom Mauser based rifle.

I like my little 550 Gibbs.

Someone else must as well, Hornady has sold about thirty sets of dies.

Physically speaking and in proportional terms it would appear that the 550 magnum is to the 458 Lott very much the same as the 458 Lott is to the 405 Winchester. Quite a jump! I guess the Zim outfit wanted to equip it's PH's with some real stoppers!

quote:

I like my little 550 Gibbs.

Someone else must as well, Hornady has sold about thirty sets of dies.

Rich, you always have been a trend-setter :-)

I have quite an audience, here and elsewhere...

I am reminded of a story of a small company being audited by the IRS. The agent asks the owner how many people he has working for him.

His answer was pretty spot on. He says, "I have ten people working FOR me, about that many working against me, and six more I am not sure of, so the total would be twenty-six".

Here, I have about ten-percent who like me, ten-percent who dislike me, and the other eighty's opinion changes from week to week.

That said, about ninety-nine-percent of the members can't see me post without clicking on it; just to see if it is going to draw a crowd.

It keeps me going thru the Agent Orange surgeries...

Rich

You are The Man! I'm definitely on the 10% "Like" side :-)

My 550 Magnum weighs 11 pounds and that is far too light for 8000 ft pounds. Folks that shot mine versus Neal's slightly heavier gun can attest to that. I suppose if you're a PH and carry it 100 days a year then 10.4 makes sense.

quote:

Originally posted by Biebs:
Wayne at AHR chambers rifles in the 550 Magnum, based on CZ 550 actions.

I think mine was the first one Wayne built, then he built one for himself because he liked it so much.

quote:

Originally posted by tiggertate:
My 550 Magnum weighs 11 pounds and that is far too light for 8000 ft pounds. Folks that shot mine versus Neal's slightly heavier gun can attest to that. I suppose if you're a PH and carry it 100 days a year then 10.4 makes sense.

It would help if yours had a longer LOP for those of us in the Ape-Armed club. I have fired that one a few times too many. A couple of your loads were down right nasty!

Andy B

Harry,
I think i only shot your 550 in the scant stock and hex sights -- and it was far too light!

quote:

Originally posted by jeffeosso:
Harry,
I think i only shot your 550 in the scant stock and hex sights -- and it was far too light!

That's the one. Jim Brockman finished it for me. It was from the original 550 group buy. I need to add two pounds to it. But at this point I'll probably sell it before I put more money into it. At 62 it's just more than I want to play with. The 458 and 500 AR are just right.

Andy, I bet you've spent more on stock extensions than I have on my thirty year old boat!