500 Rigby?

09 May 2014, 23:33

416Tanzan

Yes, RIP should fill in the details.

HOWEVER, the 500 AccReloading Nyati is also part of the equation.

The 500 Mbogo is 3" Rigby case necked up to .510".
The 500 Accurate Realoading is a shortened Rigby case (2.65") necked up to .510". (The original 500 AccRel has a 1.25" freebore, while the 'Nyati' version has a 0.252" freebore.

Basically, a person must decide how much energy they intend to generate and to hunt with. The short case will do 7000-7200 ftlbs and it fits in standard length actions. If someone has a magnum length action like the CZ 550 safari, then the 500 Mbogo will fit nicely and generate 8000 ftlbs.

I debated the two in my own mind about three years ago and decided that I wanted to try a smaller action and only planned on hunting with 6500-7000 ftlbs. So Jeffeoso's 500 Accurate Reloading became my choice. The Rigby case head is a nice platform for 50 cal.

10 May 2014, 00:48

capoward

Tanz,

I agree with the data...

But I believe folks need to focus primarily on the action being used and the secondarily on the .500" or .510" caliber cartridge that properly fits that action length.

As they say, one can always load down to any performance level desired but can only load up so far...

10 May 2014, 05:37

RIP

quote:
Originally posted by 338User:
Has anyone necked up the 416/450 Rigby case to 500 (.510) If so how does it perform? Someone must have done this!

Yep, John Buhmiller did it in the 1950s, Dave Estergaard dummied it up in the 1990s but decided to go with .475-cal instead,
and I finally did it in 2008,
called it the 500 Mbogo, aka "50-08," "Fifty Aught Eight."
It is simply a neck-up of Dave Estergaard's 470 Mbogo to .510-caliber, with brass lengthened to 3.000" maximum.
Throat: 0.500" of parallel-sided free-bore of .511" diameter, 1.5-degree leade.

http://ammoguide.com/?catid=608

The 500 Mbogo, performs very well.
Dave Manson made the reamer.
Quality Cartridge made the brass.
Redding made the reloading dies before they quit making anything for 50-cal and above.

2835 fps with 450-grain GSC HV required 115.0 grains of Benchmark Extreme from Hodgdon,
which means ADI's Benchmark 2 (BM2).
That is just over 8000 ft-lbs KE.

2654 fps with same bullet and 105.0 grains of Benchmark Extreme/BM2, with filler, was a 0.75 MOA load in my rifle.
The faster load above was about 1.5" at 100 yards for 3 shots.
Maybe I flinched? Nah, had to be a barrel nodal thing.

So I shot a buffalo with the more accurate load. Here is a photo of his reaction to impact at about 75 - 80 yards, snagged from the video:

Case capacity is midway between 500 A2 and 500 Jeffery.
Use any 500 A2 data and add a grain or two of powder,
it will equal or surpass the 500 A2 at same pressure.

The buffalo-killer load I used in Tanzania (Saeed Expedition 2010) was equivalent to a 500 AR Nyati load.
The 500 Mbogo can also be loaded down to 500 NE levels, with slow powders, or fast powder and filler.
Also great with milsurp and heavy target bullets like the Hornady A-Max 750-grainers.
The 500 Mbogo does it all, in a CZ 550 Magnum action, or other .416 Rigby-sized action.

10 May 2014, 08:47

338User

quote:
Originally posted by RIP:
quote:
Originally posted by 338User:
Has anyone necked up the 416/450 Rigby case to 500 (.510) If so how does it perform? Someone must have done this!

Yep, John Buhmiller did it in the 1950s, Dave Estergaard dummied it up in the 1990s but decided to go with .475-cal instead,
and I finally did it in 2008,
called it the 500 Mbogo, aka "50-08," "Fifty Aught Eight."
It is simply a neck-up of Dave Estergaard's 470 Mbogo to .510-caliber, with brass lengthened to 3.000" maximum.
Throat: 0.500" of parallel-sided free-bore of .511" diameter, 1.5-degree leade.

http://ammoguide.com/?catid=608

The 500 Mbogo, performs very well.
Dave Manson made the reamer.
Quality Cartridge made the brass.
Redding made the reloading dies before they quit making anything for 50-cal and above.

2835 fps with 450-grain GSC HV required 115.0 grains of Benchmark Extreme from Hodgdon,
which means ADI's Benchmark 2 (BM2).
That is just over 8000 ft-lbs KE.

2654 fps with same bullet and 105.0 grains of Benchmark Extreme/BM2, with filler, was a 0.75 MOA load in my rifle.
The faster load above was about 1.5" at 100 yards for 3 shots.
Maybe I flinched? Nah, had to be a barrel nodal thing.

So I shot a buffalo with the more accurate load. Here is a photo of his reaction to impact at about 75 - 80 yards, snagged from the video:

Case capacity is midway between 500 A2 and 500 Jeffery.
Use any 500 A2 data and add a grain or two of powder,
it will equal or surpass the 500 A2 at same pressure.

The buffalo-killer load I used in Tanzania (Saeed Expedition 2010) was equivalent to a 500 AR Nyati load.
The 500 Mbogo can also be loaded down to 500 NE levels, with slow powders, or fast powder and filler.
Also great with milsurp and heavy target bullets like the Hornady A-Max 750-grainers.
The 500 Mbogo does it all, in a CZ 550 Magnum action, or other .416 Rigby-sized action.

Thanks RIP, and everyone else who contributed, just what I needed.

10 May 2014, 08:55

RIP

Welcome, 338User,
It is fun to stroll down Wildcat Memory Lane.

Reamer drawing dated March 2007:

500 Mbogo rifle, the first, with 1:10" twist barrel made by Harry McGowen and son,
just before they sold the firm to the current Montana owners, is shown below.
Barrel is 25" long, with an integral island for rear sight and secondary recoil lug.
Dry weight of rifle, without scope, is 10.0 pounds exactly:

500 Mbogo rifle, the second, with 1:9" twist Pac-Nor barrel cut to 23" length, No. 6 sporter contour.
Rifle weight as shown is 9.5 pounds, and about the same in a CZ/B&C "Kevlar" stock which awaits, if the walnut ever cracks,
though I like this hogback as it is: