They said this site is the place to ask so I'm asking. I have been unable to get or find any load data on the .450 Rigby. Anyone out there got any they can share? Lawdog

Lawdog,
I can give you some from quickload, if you like. Email me with 2 or 3 powders, and 2 or 4 bullets. with barrel length.

DO NOT USE --standard load warning__
h4350 97 grains, woodleigh 500, 24" barrel, about 2250...

jeffe

Just curious but the 450 Rigby is a beltless 460 Weatherby so couldn't you use reloading data and starting loads in the velocity range your looking for from any manual that has 460 Weatherby loads. The only consideration is the Weatherby freebore but starting loads and mid range loads should be fine shouldn't they. From there you could just work up.

470 Mbogo

[ 01-01-2003, 05:36: Message edited by: 470 Mbogo ]

470,
quickload calls the rigby being 133 grains of water, and the 460 being 142... 7% less case. It's got more taper and neck, i think.

jeffe

Jeffe,
I can't very well argue with quickload but the published load data for all three, the Rigby, the Dakota and the Weatherby is identical. I got mine from Dakota, in fact, and was informed that they basically used a reduced Wby loading for their version. Since they load cooler than Wby and hotter than Rigby, you can take Dakota data and reduce if further. I use 105-106 gr. of IMR 4350 to get around 2300 fps. That's about 6,000 ft. lbs. or 20% more than the classic Nitro Express calibers. Ought to be enough!

Old Sarge,
This might sound rude, but I sure dont mean it to. this stuff is nearly always "interesting"

The weatherby is a high pressure (64K), the dakota is high (60k) as well, and the rigby is 48k. the rigby has TONS more taper in the case. It's important to remember that the weatherby is an IMPROVED verson of a 416 rigby case, with a belt, not just a necked up.

This is the program that cartridges of the world uses to project it's loads/exterior ballistics.

From Quickload
460 weatherby
pressure 63816 psi
case length 2.913
case cap. water 141.79gr
remaining capacity after 500 woodleigh 118.54gr

450 dakota
pressure 59465 psi
case length 2.890
case cap. water 137.0 gr
remaining capacity after 500 woodleigh 114.573gr

450 rigby
pressure 47862 psi
case length 2.902
case cap. water 133.01gr
remaining capacity after 500 woodleigh 110.512gr

458 lott (just for a baseline)
pressure 62336 psi
case length 2.80
case cap. water 110.0 gr
remaining capacity after 500 woodleigh 85.491gr

While one might "get away" with using bottom weatherby loads, according to the pressure used in the loads, the rigby is MUCH lower. Some much that I would wager a bottom weatherby load is above the max pressure of a rigby 450. After all, the 458 lott is loaded to a higher pressure, and delivers simalar performance as a 450 rigby.

So, in effect, you might could further reduce the weatherby loads, as the case is smaller, but you would be at top operating pressure for the standard on the rigby. if you rebarreled/bored a 416 rigby to 450 rigby, would it hold the pressure? it should, but that's not where it's designed to operate.

Hi Jeffe,
I have both rounds here and at the shoulder a fired 450 Rigby brass only measures .0155 less than the 460 Weatherby so the taper isn't all that much different. From the base of the case to the shoulder there is only .024 difference so I think the cartridges are a lot more similar than the info that you were given. I don't have a fired 460 Weatherby case so I can't compare grains of water. I would also think that the working pressures given as with the 416 Rigby is the ideal for the cartridge but as everyone knows the ballistics can be improved on substantially within safe limits. Even reloading manuals show higher pressure loads for the 416 Rigby. That is why I recommended starting with the moderate loads for the 460 Weatherby.
Take care,
470 Mbogo

Hi Jeffe,
Just for a comparrison of info the Accu Load shows the 460 Weatherby holds 145.5 grains of water and the 450 Dakota to hold 145 grains of water. They don't list the water capacity for the 450 Rigby but when you put the cases side by side they look identical other than the belt and the shoulder angles.
Load from a Disk the older version that I have lists the 460 Weatherby as a water capacity of 138 grains so you see where the discrepencys arrive.
470 Mbogo

470/Old sarge,
Guys, ya'll might very well be right.. I wish I had both to measure. I dunno on these, as the only case i've got is a 460... and it's a nice condition in my collection, so i wont be tearing it down.

interesting, 470, that they look that close.. wish i could see em both, as I think they are both pretty durn cool

happy new years
jeffe

Hi Jeffe,
I looked through my stuff and I only had this one crappy picture. I couldn't lighten it up but you will see what I mean.

I hope you can make it out OK From left to right they are 475 Nitro, 450 Rigby, 470 Mbogo, 460 Weatherby
Take care,
470 Mbogo

[ 01-01-2003, 10:00: Message edited by: 470 Mbogo ]

470 Mbogo
COOL!!!!

thanks for posting that
jeffe

Hi Jeffe,
Here is a picture of the 416 Rigby, 450 Rigby and a 470 Mbogo. You can see that the taper is out of the 450 Rigby compared to the 416 Rigby case. I wish I had a digital camera.


Take care,
470 Mbogo

jeffe,

Unlike the 416 Rigby, the 450 Rigby has a minimum taper. In fact, I think it has more case capacity than both the 450 Dakota and the 460 Weatherby. From my own measurement of the 460 Weatherby, it can contain about 138 grains of water. I have not done measurement with my 450 Rigby yet. I just fired form some cases the other day with some new Horneber 450 Rigby brass. I hope to have a chance to measure it soon. Thanks.

Jeffe,
I have some fire-formed Rigby cases that are "sort of" spare so I could send you one if you want. I must point out, however, they were formed from .416 Norma brass so the necks are a little short. That could make a big difference in the grains of water test though it would show clearly how straight the case is. I've also got a whole box of Bertram .450 cases but I ain't lettin' go of none of them! This whole thing is a good lesson in using multiple sources of data. Typos and differences of opinion are the bane of the scholar search for whatevertheHell Truth might be.
Good Hunting, Brother.

Me thinks some folks are relying too much on data from software programs which are notoriously wrong when it comes to big bores.

Simply consider the case dimensions for each cartridge and you will understand that there is little performance difference between them. The cartridge companies show performance differences by ignoring comparable chamber pressures.

The Dakota and Rigby cartridges are ballistic twins. The Weatherby with it�s goofy shoulder does allow for marginal gains in case capacity. However, remove the goofy freebore from the gun, and all exhibit similar (within a small degree difference) chamber pressures and velocity performance. There is nothing �huge� in difference between these cartridges. You gotta want to split hairs to find any measurable difference.

These are SAAMI specifications....

.450 Dakota
Base Width - .5820"
Base to Shoulder - 2.3240"
Base to Neck - 2.40"
Shoulder Width - .560"
Shoulder Angle - 26 degrees
Case OAL 2.90"

.450 Rigby
Base Width - .5772"
Base to Shoulder - 2.342"
Base to Neck - 2.401"
Shoulder Width - .570"
Shoulder Angle - 40 degrees
Case OAL 2.894"

.460 Weatherby
Base Width - .5820" (in front of belt)
Base to Goofy Shoulder - 2.345"
Base to Neck - 2.494"
Shoulder Width - .5610"
Goofy Shoulder Angle - Ogee Shoulder (Whatever)
Case OAL 2.913"

In my opinion, you can take all three cartridges and load them with the same powder charge weights with the same bore configuration (no goofy freebore) and achieve comparable velocities. There is not more than 3% performance difference between them.
.
.

[ 01-01-2003, 22:12: Message edited by: Zero Drift ]

I read a very good article by John Barsness on improved cartridges and what to expect as far as gains in velocity. After all his research and studies he came up with a relative constant that he figured was close enough to be used as a constant.
If you improve a cases capacity with equal pressure you will gain 25% of the percentage of the gain. The same goes for increasing the bore diameter, you will gain 25% of the percentage of the gain.
So if the case capacity you start with is 100 grains and you improve the case to 110 grains the 10 grains or 10% of the original case will yield you a 2.5% increase in performance at the same pressure. So if your cartridge would push a 180 grain bullet at 3000 fps you could expect it to gain 3000 X 1.025 = 3075 fps. This 75 fps gain does seem to fit the mold of most of the improved cartridges. If the yield is more then it is being loaded to higher pressures. If your wildcatting a cartridge and are interested in the article it is in Hanloader June 1997 No. 187
Take good care,
470 Mbogo

Boy was I given the right information. This is the place to ask about big bores. Thanks guys I gotten more information than I ever got asking before. Hope everyone has a great New Year and again Thank You. Lawdog