I know the Dakota and the Rigby are both on the same parent case but I can't find the dimensional differences between the two. They must be very close. Are they interchangable? That would be too much to hope for.
In any case can someone give me the dimensional differences? Please.
I had a change to shoot the Rigby in a very light rifle and loved it. Not punishing at all. My Dakota is not nearly so nice to shoot.

My .450 Dakota isn't exactly a maiden's caress but here's the specs:

I'm curious as to why the Rigby would have been so different for you, it should have been similar. 500 grains at 2,400+ is 500 grains at 2,400+.

There is no significant difference between the 450 Dakota and the 450 Rigby.
Any differences in recoil would be attributable to the rifle build, not the cartridge build.

Note the "Adv.Water - 145" in adrook's posting from Dakota: Advertized Water?

AEM says they measured it at 130.6 grains gross water capacity for the 450 Dakota.

Comparatively, AEM says the 460 Weatheerby has 145.5 grains water.

Andy has pointed out the difference in old and new brass. I do not think the new brass is anywhere near the "advertized water."

I will measure some new brass, headstamp:

Dakota Arms

O

450

If you can navigate the maze of a search, you might find where we have spelled out the comparison specifications between the Rigby and Dakota 450's once upon a time.


I might be able to find that comparison tabulation and measure my brass, later ...

I knew the Rigby, Dakota and Weatherby were all ballistically very similar. I guess the stock design had something to do with the acceptable level of recoil in this light rifle I fired. It was still a jolt but not painful. My Dakota is on a CZ action and it gives me blurred vision after 3 rounds. I want no part of a Weatherby. I had that experience once.
I looked at the parent cases and compared the shoulder locations but I just couldn't find the Rigby shoulder location dimensions for the 450: 416 is readily available.
Thanks for the feedback.

Kind of a long shot, but since CZ is now chambering the 450 Rigby, you might want to give them a call and see if they would be willing to share the case specs. with you. Dont know if they would do that or not, but it might be worth trying.

The 450 Rigby specs are published in CIP. Mr. Roberts saw to that.
It is all very clear cut.
That is the standard for the 450 Rigby.
It's been posted here before.
I'll look that one up again too, later ...

Until then, IIRC, it is not a simple neck up of the .416 Rigby. The 450 Rigby shoulder is blown out to greater diameter than the .416 Rigby shoulder (less body taper) and the angle is changed from 45 degrees (for the .416 Rigby) to about 40 degrees (for the 450 Rigby).

The base to shoulder distance is less on the 450 Rigby than the 450 Dakota, IIRC, but the base diameter is slightly greater overall for the 450 Rigby.

No significant difference, really, between the 450 Dakota and the 450 Rigby.

The Dakota and the 458 lott are pretty close in being the same in Volocity. The lott can push the 500gr bullet over 2400 fps.

quote:

Originally posted by jro45:
The lott can push the 500gr bullet over 2400 fps.

The Ackley will get 2400 fps with a 500 grain bullet, but I think you would be hard pressed to get that out of a Lott.......JMHO

quote:

Originally posted by RIP:
The 450 Rigby specs are published in CIP. Mr. Roberts saw to that.
It is all very clear cut.
That is the standard for the 450 Rigby.
It's been posted here before.
I'll look that one up again too, later ...

Until then, IIRC, it is not a simple neck up of the .416 Rigby. The 450 Rigby shoulder is blown out to greater diameter than the .416 Rigby shoulder (less body taper) and the angle is changed from 45 degrees (for the .416 Rigby) to about 40 degrees (for the 450 Rigby).

The base to shoulder distance is less on the 450 Rigby than the 450 Dakota, IIRC, but the base diameter is slightly greater overall for the 450 Rigby.

No significant difference, really, between the 450 Dakota and the 450 Rigby.

Rip, do you know where to find the CIP dims on the net, I have looked to solve this conundrum before & never come up with a definite answer? Some sources such as this 450 Rigby state that it is the 416 case necked up with no change, what is one to believe?
Steve

Shinzo I found a CIP site.

I hope the translator works in the link. Otherwise it is in French.

quote:

Originally posted by Whitworth:

quote:

Originally posted by jro45:
The lott can push the 500gr bullet over 2400 fps.

The Ackley will get 2400 fps with a 500 grain bullet, but I think you would be hard pressed to get that out of a Lott.......JMHO

Dittos, unless you use a 26" barrel and run high pressures, no way the lott will run 500's @ 2400 fps. I had to run compressed charges just to get 2300 fps.

While the lott is a good round, it is nowhere as flexible as the larger cased 45's if you really want to push 500's past 2200 fps.

quote:

Originally posted by jro45:
The Dakota and the 458 lott are pretty close in being the same in Volocity. The lott can push the 500gr bullet over 2400 fps.

Not exactly. I've yet to see a Lott get 2,400, let alone over that. The Dakota/Rigby can do 2,600 if you want to push it but 2,400-2,500 is easily attainable with mild pressure. No Lott can do that.

Shinzo,
There is a lot of bogus info on the 450 Rigby floating around out there, and I have been guilty of parroting it from others.

Let me set the record straight.

"The Gospel of Rigby, Verse 450" is found on page 116 of the 119-page chapter "Drawings of Rimless Cases" in the Bible-CIP.

"The Gospel of Rigby, Verse 416" is found on page 115 of the same Bible-CIP chapter.

416 Rigby:
Shoulder cone angle = 89 degrees 45' 32"
Length base to shoulder = 59.77mm
Shoulder diameter = 13.74mm

450 Rigby:
Shoulder cone angle = 80 degrees 04' 59"
Length base to shoulder = 59.50mm
Shoulder diameter = 14.50mm

Verily, the 450 Rigby is not simply a neck up of the 416 Rigby ... coom-bah-yah ... amen.

quote:

Originally posted by adrook:

quote:

Originally posted by jro45:
The Dakota and the 458 lott are pretty close in being the same in Volocity. The lott can push the 500gr bullet over 2400 fps.

Not exactly. I've yet to see a Lott get 2,400, let alone over that. The Dakota/Rigby can do 2,600 if you want to push it but 2,400-2,500 is easily attainable with mild pressure. No Lott can do that.

Under normal circumstances I would agree. I've gotten a little over 2,400 fps out of my Ruger No.1 though and at very reasonable pressures, even using the long 500 gr. TSX!! Of course, the only reason I can acheive these velocities at reasonable pressures is because my rifle has been throated so that I can load my rounds up to .500" longer than the standard .458 Lott OAL. That's the beauty of the Ruger No.1. It's strong, ultra reliable, good looking, short and handy, and it doesn't care how long your cartridge is!!

Unless you have the option of seating your bullets out further or go with a 26+" barrel
2,400 fps is really hard to acheive. Some say that they can't reach 2,300 in 22-24" barrels.

BTW, my only knock on the No.1 is that it isn't made to handle recoil well. I don't know if I'd want to shoot a Ruger No.1 chambered in .450 Dakota, .450 Rigby, or .460 Wby without a brake. The plain ol' .458 Winchester hurts in my No.1! I'd like to have one chambered for the .550 Magnum,.600 JDJ, or .600 Overkill( if it will handle the .600 OK) with the factory "brick pad" and no brake, just to photograph people's expressions after pulling the trigger!!!! OOOUUUCH!!!!!!

I wonder why Ruger quit making their No.1's with the old deep throat design? Accuracy? It didn't hurt my rifle's accuracy at all when I throated mine.

quote:

Originally posted by .366torque:
Shinzo I found a CIP site.

Thanks for that .366, from what I can find on it, there is no listing/archive of ammunition specifications which is what I would like to find. Not sure if there is such a thing in the public domain other than the likes of Municion.org & ammoguide.com which suffer from being interactive & thus susceptible to error, though this is likely to be slight.Neither of them list the 450 Rigby in any case hence my frustration
Steve

quote:

Originally posted by RIP:
Shinzo,
There is a lot of bogus info on the 450 Rigby floating around out there, and I have been guilty of parroting it from others.

Let me set the record straight.

"The Gospel of Rigby, Verse 450" is found on page 116 of the 119-page chapter "Drawings of Rimless Cases" in the Bible-CIP.

"The Gospel of Rigby, Verse 416" is found on page 115 of the same Bible-CIP chapter.

416 Rigby:
Shoulder cone angle = 89 degrees 45' 32"
Length base to shoulder = 59.77mm
Shoulder diameter = 13.74mm

450 Rigby:
Shoulder cone angle = 80 degrees 04' 59"
Length base to shoulder = 59.50mm
Shoulder diameter = 14.50mm

Verily, the 450 Rigby is not simply a neck up of the 416 Rigby ... coom-bah-yah ... amen.

yeah, well that looks fairly definitive. Oooooh Yeeeeah
This here CIP bible thing, where does one find such a tome? Bet its bl**dy expensive too.
Thanks for the info. Looks like you could use Dakota ammo in a Rigby at a pinch but not 'tuther way round, don't think I'd like to make a habit of it though, it would give some bad case stretching, maybe even head separation although the shallower shoulder angle of the Dakota round would take up some of the difference in headspace.
Steve

quote:

Rip, do you know where to find the CIP dims on the net, I have looked to solve this conundrum before & never come up with a definite answer? Some sources such as this 450 Rigby state that it is the 416 case necked up with no change, what is one to believe?
Steve

Shinzo, I wrote the article you are refering to, and clearly state that I fire-form the cases, not just neck it up.

The ammo I saw specified 2340fps on the box and I think it was 500 grs. That is a good enough velocity for me.
Thanks for all the data Gentlemen. I'll try to reconcile it.

quote:

Originally posted by Karl S
Shinzo, I wrote the article you are refering to, and clearly state that I fire-form the cases, not just neck it up.

Karl, the confusion is obviously mine in this case, when you referred to fire forming I took that as meaning to enlarge the neck to .45 cal. yes, I do know what is commonly meant by fire forming & realise that this is not the most common use for it but I guess I was put off in this case by the opening sentence of your article & I quote " Paul Roberts, then owner of Rigby of London, developed the .450 Rigby Rimless Magnum in 1995 by necking up the .416 Rigbys case to take a .458 bullet (no other changes)." Seeing as you make no other references to dimensional changes I hope you can understand my confusion. I'm pleased to have had this myth laid to rest.
Steve

Shinzo,
I shall consult with my CIP Pastor and see about revealing those verses to the public, by this weekend when I measure those 450 Dakota gross water capacities. I will try to use CIP holy water and pray that the 450 Dakota will also be listed as a verse in The CIP Bible some day.

quote:

Originally posted by RIP:
Shinzo,
I shall consult with my CIP Pastor and see about revealing those verses to the public, by this weekend when I measure those 450 Dakota gross water capacities. I will try to use CIP holy water and pray that the 450 Dakota will also be listed as a verse in The CIP Bible some day.

It may be listed but I'll bet it won't be listed in the part where the words are written with the red lettering! Not unless you have truly gained the favor of that "AUTHOR ABOVE ALL OTHER AUTHORS !!"

......and no, I ain't talkin' about Craig Boddington!!!

srshooter,
It will indeed require a papal dispensation to publish those verses in their entirety, red ink and all.
Here is the gross water capacity of once-fired 450 Dakota brass, the newer headstamp "Dakota Arms 450":

450 Dakota: 138.8 grains water

That was from weighing 5 cases with and without water, and averaging the differences.
That is 139 grains to the nearest grain, and that is very close to 460 Wby capacity.

If sumbuddy with a 450 Rigby would measure their 450 Rigby brass and tell us what make the brass is, that would be a comparison of note.

quote:

If sumbuddy with a 450 Rigby would measure their 450 Rigby brass and tell us what make the brass is, that would be a comparison of note.

RIP, I wish I could help you, but I am kind f far from a electronic scale. If I make it back before you guys have data (in about 4 weeks only), I can do it.

My guess is that the reason the recoil was different was due to the velocity of the loads. In my 450 Dakota...loads over 2500fps have a lot more recoil than those around 2400fps.

Roscoe, I've noticed the exact same thing with multiple rifles. Once you get near or just above max loads recoil seems to go up significantly. None of the recoil calculators take it into account so maybe it's a figment of my imaginination. Once I get on the warm side a particular handload, the pressure increase per grain goes up dramatically as does the recoil. Is there a relationship between pressure and recoil? I think the recoil calculators assume it's linear with velocity and powder charge, but it's not. My 375 H&H loads shooting 350g Woodleighs at 73g (2460 fps) kick significantly more than 72g (2350 fps), yet I can't tell the difference between the recoil using 71g and 72g. I notice the same thing with my 270 and my 45 Super.

Regards,
Chuck

quote:

Originally posted by chuck375:
... My 375 H&H loads shooting 350g Woodleighs at 73g (2460 fps) kick significantly more than 72g (2350 fps) ...

Chuck,
Something is screwy (or "scwewy," as Elmer Fudd would say) if one grain of powder increases the velocity of your .375/350-grainer by 110 fps. Typo?

No I chronographed a 3 shot group. That's what I typically see if my load is a little warm. My primers looked good, but extraction was just a tiny smidge harder (always a sign to back off), no extractor marks on the cases. I backed off one grain and all is well. I've seen the same phenomenon with my 270 when I get just over where I should be during load development.
I think I can get the 350g Woodleighs up to 2400 fps plus with N560 with no pressure issues.

Regards,
Chuck

Seems jeffeosso and Forrest got the papal dispensation for one chapter of the CIP Bible, posted on the second post of the "Reference" thread on "Gunsmithing" forum. Lessee if I can copy it. Look for the Rigby verses here, pages 115 and 116, for 416 Rigby and 450 Rigby respectively:

http://www.poliisi.fi/intermin/images.nsf/files/AE55118...DE/$file/TABIcal.pdf

Chuck and RIP,

I am a velocity freak and tend to push reloads as fast as I can, but 100 fps increase w one grain powder means you are at or beyond max load with the previous powder charge!

Yep,
Not my data! Even a cwazy wabbitt huntew would be vewy caweful if he got such data.
Something vewy scwewy thewe.
Cwazy data! Scawy data!
I would weduce by mowe than one gwain if something like that happened to me!