Rookie Question,

What are basic case dimensions, powder charge, powder, and velocity for this 416 Rigby x 475?

Do you use 450 Dakota brass or Rigby brass?

Andy

Andy,

You are in luck! The 'creator' of this round is a Member here.

I'm sure he'll be along to answer your query.

George

www.470mbogo.com

jeffe

quote:

Originally posted by Andy:
Rookie Question,

What are basic case dimensions, powder charge, powder, and velocity for this 416 Rigby x 475?

Do you use 450 Dakota brass or Rigby brass?

Andy

Until Creator Dave Estergaard gets here:

case length: max 2.945" trim to 2.935"
shoulder angle: 35 degrees
shoulder diameter, minimum chamber: 0.5750"
boltface to shoulder distance: 2.4979"
boltface to start of neck: 2.5300"

I use a stash of BELL .416 Rigby basic or properly headstamped Quality Cartridge brass.

For Dave: Is Jamison making .470 Mbogo brass now?

Sample loads in a Pac-Nor 25" stainless barrel:

.474/500gr Barnes XLC with RL-15 110 grains >>> 2561 fps, my favorite load.

.474/500gr North Fork FP with H4831SC 110 grains >>> 2170 fps, accurate and gentle like a .470 NE.

.475/500gr Barnes Original with RL-15 115 grains >>> 2685 fps, no pressure signs, one more grain would be over 2700 fps.

This is ancient history, but R&D at HA!/DOA has kept me too busy to revisit the .470 Mbogo for that foray past 2700 fps with a 500 grainer. Also, common sense dictates: "Why bother?"

Hi Andy
I would say that RIP has answered all your questions. The starting brass is the 416 Rigby cylindrical brass made by Jamison.

Ron we have a bunter at Jamison for the 470 Mbogo but for some reason the engraver has it stamped as Mbogo 470. Minor detail due to the quality of the brass. I would imagine that Jamison would supply you with headstamped cylindrical brass if requested.
Take good care,
Dave

A really GREAT cartridge!!!

Dave,
that jamison brass must read "mbogo 470" only NORTH of the border

In all honesty, for anything other than a 100% dedicated stopping (stomping?) rifle, Dave's round is probably the best of ALL the over .45 bolt gun guns, commerical or no. In fact, a man would not be poorly served WITH it as a stopping rifle, 7000lb-ft can't be wrong

great down range, great bullets, easy to smith, and a tremendous guy invented it...

and the 470 AR is the Mbogo's kid brother... little shorter, little slower!!

jeffe

The 470 mbogo is what should have been invented instead of the 416 rigby.

i believe that a certain mr. selby would disagree with that statement.

no disrespect intended to the 470 Mgobo

quote:

Originally posted by bearhunter762:
i believe that a certain mr. selby would disagree with that statement.

Only until he shot game with it

jeffe

Joe O'Bannon who owns JR Outfitters in Florida where they shoot alot of water buffalo has also been hunting in Tanzania professionally for many years. This year he got a 500 NE but up until now he has been using three 470 doubles. He had a Rigby, a Kreighoff and a Merkle. He has had consistent problems with the 470 Woodleigh solids not staying on track but rather veering off side after they enter an animal. Something to keep in mind when reloading the 470 Mbogo.

VBR,


Ted Gorsline

Ted,

Thank you all.

Dans praise is especially meaningful.

"Veering off track" with a 470 nitro's FMJ might have more to do with the extremely poor stability of 470 nitro bullets fired in a 1-21 inch twist which is I think standard for that caliber.

The 500 nitro is better stabilized at I think 1-15???

And I thought a 458 Winchester was slow! (1-14).

What is the twist of the 470 Mbogo?

Andy

I believe twist is very important in external ballistics, not so much in terminal ballistics, though extra twist doesn't hurt with either at normal hunting ranges ... say within 500 yards, or maybe 1000 yards if the shooter is really good.

My .470 Mbogo is a 16" twist.
My .470 Capstick is a 10" twist.
my .470 NE is 18" twist (IIRC) but all deliver bullets well to the point of aim inside of 300 yards, and I have even shot the Merkel to crossed groups at that range.

I think a 21" twist is sufficient for external ballistics with any ".470" with 500 grain weight bullet.

The Flat Nosed solid bullet I do believe is much superior for penetration.

I base these summary conclusions on limited shooting of .416/380gr GSC FN's, .509/570gr GSC FN's, and .474/500gr North Fork FP solids of monometal copper into cape buffalo, Bison bison, and the "IRON BUFFALO" of alternating plywood and water compartments. I compared the Woodleigh FMJ .423/400gr and the Barnes .474/500gr Brass round Nose to the GSC FN's and North Fork FP's of the various calibers above and .375/300gr and 270gr as well.

There is just no need for me to shoot game with any round nose solid if I can find a flat nose instead.

I get the impression that any of the Round Nose FMJ solids of tradition (and the Round Nose brass monolithics too) will not penetrate as deeply before tumbling and veering off course and fishtailing their bases. The Flat Nose monometal solids are significantly better at straight line penetration depth.

None of us here has statistically significant data on his own, but I think it is collectively piling up.

Shoulder stabilization and some improved cavitation must combine in the flat nose for better straight-line penetration depth.

Looking back through my loads, I noted that I did try the H4831SC in the .470 Mbogo: 110 grains with a North Fork Flat Point Solid gave 2170 fps in my 25" barrel of 16" twist.

This makes a sweet practice load for the .470 Mbogo, accurate and gentle on the shoulder. I've got lots of old Barnes Original 500 grain RNSP and brass RN solids that would be good for plinking with, and not useful for much else.

The .470 Mbogo has case capacity nearly identical to the .470 NE, so it is not surprising that the George Hoffman .470 NE load works well in it too, and pressures with that would be around 35K PSI.

What Fun!

Now for the scientists to pick me apart ...

Andy,
woodleighs wander in 470s.. that' bullet shape.. though some may say otherwise...

the warning is for woodleigh solids, not the 470 mbogo.

if a bullet is unstable due to twist, it will both yaw in flight, could keyhole on target and WILL sprawl on impact... sprawl should be considered radical path changes (think BB shot into an ammo can) not drift....

though someone is bound to disagree....

btw, more twist, witih the same load, means more pressure

jeffe

Thank you all for the 470 Mbogo lessons.

A 1-16 twist will give a 500 grain .474 1,875 revolutions per second at a sensible 2,500 fps.

that is about as stable (or unstable) as a 458 Winchester at 2150 fps and a 1-14 twist.

I was thinking of more like 2,450 fps as thats just all the fun I can stand!

In a 1-12 twist that would give you alot more stability (2,450 rev per sec).

I am surprised you can load it up so fast (2,700 fps). Wow!

The main advantage to me of a .474 over a .458 on this case is when using a solid for elephant.

I was also excited to see how similar the expansion of Daves 500 grain Swift was to the 450 grain North Fork bonded soft point I used in my 450 Dakota at similar velocity. (845 vs 82 caliber).

So big difference will be in solids on elephant. Anyone used it yet???

Andy

Andy

Geez!! First time I ever saw "500 grains", "2500fps", and "sensible" in the same sentence. Did you get heat stroke over there?

I wish I had some elephant shooting experience with North Fork Flat Point Solids.

I did shoot the "Iron Buffalo" (plywood and water alternating), some may recall. Before dismissing it as an "un-elephant-skull-like" penetration medium, consider that it is a medium that is more like a Texas Heart Shot on a big bovine or even an elephant. It may be an apple when you want an orange. However it is a test medium for penetration when comparing one variable to another, such as twist rate or bullet velocity, with other parameters fixed.

Fixed: North Fork .474/500gr Flat Point Solid of monometal copper. Nowadays they may be .475 and have different band structure, but the older ones shot well in all my rifles.

Vary impact velocity for same twist:

Data points below have so far been all the same for penetration: they bounce off the eleventh "1/2 inch thick" plywood board having traversed 11 compartments of water about 8" thick between boards. A four layer thickness of truck innertube is the entry to the first compartment, then water and board alternating. Water is in 2 mil plastic trash compactor bags with a wire tie. They are all key-holing through the tenth board and stopped by the eleventh. Laser straight until the tenth compartment water is entered.

.470 NE 18" twist at 2100 fps.
.470 Capstick 10" twist at 2100 fps
.470 Capstick 10" twist at 2300 fps
.470 Mbogo 16" twist at 2100 fps
.470 Mbogo 16" twist at 2500 fps

Not enough difference in twist or impact velocity to make any difference. They all penetrate the same.

The higher velocity bullets expend their energy by flinging water and board fragments into the air in a bigger splash in the first three compartments, then they all settle down to penetrate the same.

A .375/300 grain GSC FN solid at 2500 fps and at 2700 fps penetrates the same, both with 12" twist.

A .375/270 grain GSC FN solid at 2900 fps (12" twist) penetrates reliaby less than any of the loads above, .375 or .470.

A sectional density of .300 or greater and a flat nose monometal work best in the "Iron Buffalo."

Speed can't make up for lack of bullet weight, with a solid/nondeforming bullet.

Monometal bullets much over .300 SD are just too long to be practical for various reasons, but they are "enough bullet."

It ain't elephant skulls, but it is something repeatable, reliably, this Iron Buffalo stuff.

The Iron Buffalo is out to pasture now. It taught me a few things.

I have not experimented with twist rate versus penetration as Ron has. However, Art Alphin says that a faster twist gives deeper penetration, hence his recommendation of a 1-10 twist. We also know that the early 460 wby rifles with a 1-18 twist had very shallow penetration. Therefore I would go with the faster twist, just to be safe, as there does not seem to be anything gained with the slower twist.

Dan,
not picking a fight here.. just talking..
Ackley said (and I've built rifles to prove it) that faster twist, in the same load, results in higher pressure. Sometimes this results in higher velocities, as in the case of a 358 win I built with a 1x10 twist rather than 1x14.

on the 460 weatherby... I often wonder should one even take a QT (Fred Barnes' line of round indicating over twist) barrel (say 1x7) 460 weatherby... with the EXACT same bullets used on the reported failures (they were failures) would one have the same failures..

that is to say, if a bullet came apart, would a slower twist contribute to that bullet failure.

just a thought

would be interesting to talk Rip into testing on the iron buffalo

jeffe

I would go for a 12" twist on a .470 Mbogo if I had it to do again. Partly so as the bullet revolutions per second would be numerically the same as the muzzle velocity in feet per second.

Surely the extra spin has got to affect pressure and velocity a bit, but it just doesn't seem to be significant, as the rotational energy and momentum are a tiny fraction of the bullet kinetic energy and momentum based on muzzle velocity.

There have been enough jeers and cheers over the Iron Buffalo for a while.

I have 10 straight cylindrical bullets of .416/370gr North Fork copper solid, to be compared to the usual North Fork .416/370gr FP copper solid. Should not the .416 caliber cylinder penetrate less, or will it super cavitate and shoulder stabilize better and penetrate more?

And I do want to see what a 10" twist .500 A-Square and a 15" twist .50 BMG can do to the Iron Buffalo with .509/570gr GSC FN bullets at 2400 fps from each. Then see if increasing the 570 grainer's velocity to 2900 or 3000 fps (or whatever is possible from a 30" barreled .50 BMG) allows it to penetrate the Iron Buffalo any better, or just demolishes the entry end of the contraption and penetrates no better, or less if the FN expands.

Of course these are just some fundamental tricks for the science fair project in junior high school, eh? Can anyone predict the outcome for me?

Anyhoo, it has been fun to see Norbert simulate the Iron Buffalo in an amazing feat of German Under-engineering. What a switch!

He created a train of particle boards and square cross-section plastic water containers standing in a sandwich to shoot through. No Iron Buffalo skeleton required.

It is labor, time, and material intensive, so I cannot promise anything soon ...

So, back to elephant shooting and keep those reports coming.

rip...can you try some 275 gr barnes xpb's in you mbogo and see if you can get them to go 3200 fps!? plainsgame?

Hmmmm, mbogo 470 sounds like a good project on a CZ in a few years. Better get a McMillan stock with a solid fill, or a Brockman laminated job.

Jeff,

I know there were a lot of bullet failures with the .460, but also shallow penetration from bullets that did not fail. We know that yaw increases with velocity, and I wonder if the shallow penetration can be attributed to excessive yaw. A faster twist rate can reduce yaw, and perhaps that is why it is believed by some that faster twist results in greater penetration. I also recall that Norbert once posted that a faster twist rate gives greater stability of the supercavitation bubble, thus increasing penetration, but I may be misquoting him so I hope he will join in to say it the right way.

It is true that faster twist means more pressure. But the cavernous Rigby case gives up plenty of leeway in the pressure department.

With the stout bullets available nowadays, there are no real drawbacks to using more twist than needed for accuracy.

Pressure and velocity effects of the faster twists must be negligible as far as I can tell.

I have used only 12" and 10" twist barrels of .375, .423, and .458 and .510 caliber since the .470 Mbogo.

When I bought the .470 Mbogo barrel, 16" twist was the fastest that Pac-Nor offered, and I was just following the herd to that point. Now they offer faster twists in .475 caliber.

Faster twist may have marginal improved penetration. It sure can't hurt with terminal or external ballistics at hunting ranges, and it has no significant effects on internal ballistics.

Sounds like a win-win situation to me.
Use a faster twist.
Either 10" or 12" would be great on a .470 Mbogo IMHO.

However, all those .470 NE double rifles out there with 18" and 20" twists seem to have made a success of the .470 NE with the traditional bullets, ballistically comparable to a Woodleigh of today.

Must be some ballistic latitude for free-play here.

One of the advantages with the .475 - 500 grain bullet is that it's shorter than the .458 - 500 grain bullets so the slower twist rate is still enought to stabalize the bullet. With the 2500 fps velocity the 470 Mbogo is designed for the additional pressure from the faster twist rate won't make any significant difference. A 1 in 12 or 1 in 14 twist rate would be excellent with the Mbogo.
Take good care,
Dave

Dave & Rip,

I have a hogback CZ in 416 Rigby on layaway right now. Very straight grain. I do like the stock design for iron sight use.

So, if I bed and cross bolt it until hell won't have it, put a little mercury here and there, add a wonder pad and keep velocity down to 2,400 fps.....How controllable will this be? I shoot my stock 416 Rigby just fine; just have to roll with it and don't take it to hunter benchrest matches.

Thanks,

LD

Hi Lawndart,
I would use the F990 pad and keep the weight to 10.5 lbs. Loaded to 2400 fps it should be good to shoot. Have the muzzle finished to .750 at 24 inches. If you need to add weight to bring it to 10.5 lbs do it to balance the rifle. I have an Ashley peep along with the masterpiece front sight with the flourescent bead. This set up is very fast to get on target.
Take good care,
Dave

Thanks Dave,

That is easy enough.

1:8" twist for shooting high-power across the course, right?

lawndart

lawndart,
You do like Dave says, and the Lux/Hogback will be fine.

I will also do the same with a .500 Mbogo Express.

There is always a McMillan if need be.

I am going to use a 10" twist on the .500 Mbogo.

so rip...you ARE doing a 500 mbogo???
will yours be the first?
i assume it is just a neck up?

BS,
To complete the HA!/DOA prototypes:
We will soon be test firing the .427 Lapua Kifaru on a Dakota 76 African action with a McGowen stainless 10" twist barrel.

Then I am going to have a CZ 550 Magnum Lux Hogback in .300 Winchester Magnum rechambered to .307 Lapua Chui, as I found this factory barrel to be extremely accurate. The .300 Lapua Magnum reamer with .300 Weatherby throat made by Dave Kiff of PT&G will just barely clean up the .300 Winchester chamber. If there are any poor results with this re-chamber, I will just have to rebarrel.

I have a stainless .510 barrel from McGowen on order. A depth of 3.0186" from bolt face to end of chamber neck will provide a .5100" length neck when the .470 Mbogo is necked up to .500 Mbogo Express. Trigonometrically calculated using the tangent of 35 degrees = 0.70012. Still in the R&D stages, with a reamer drawing of the .470 Mbogo altered with penciled in .500 Mbogo Express specs. I don't have the reamer. I don't have .416 Rigby basic brass that is 3 inches long either. HA!/DOA shall overcome ... Indians vow to endeavor to persevere.

great news...

glad to hear about the stainless 510 barrel.

maybe someday i will be rehired to promote them

I would not be concerned about the quicker twist increasing pressure.

It does not increase pressure but does effect the pressure curve.

I was involved with the adoptation of the XM16-A2 when the USMC went from a 1-12 twist to a 1-7 twist with the service rifle, and it did not increase chamber pressure, just port pressure, 14.5 inches down the barrel.

I have shot a 1-8 375 improved for over 25 years and it is still a very low pressure ctg. (You cant cram enough IMR 4831 into the case to get into trouble).

Flash x-ray photography absolutely demonstrates a quicker twist reduces both pitch and yaw.

Only downside is that conventional (unbonded) SP bullets may fragment more with the quicker twist, But it deffinately helps a good bonded bullet or FMJ.

Alot of the FMJ failures you hear about from the 19th century to date occur because the bullet gets sideways. I want to keep a FMJ or monometal point forward at all times.

2nd rookie question? Do any double rifle makers offer a quicker than std twist in a 470 or 500?

thanks, Andy

Andy
Andy

quote:

Originally posted by Andy:

I was involved with the adoptation of the XM16-A2 when the USMC went from a 1-12 twist to a 1-7 twist with the service rifle, and it did not increase chamber pressure, just port pressure, 14.5 inches down the barrel.

I would assume the magnitude of this pressure increase toward the muzzle was small. Were there any measurable differences in velocity between the fast and slow twist barrels with the same loads?

Flash x-ray photography absolutely demonstrates a quicker twist reduces both pitch and yaw.

I'll take your word for that. Makes sense.

Andy,
Thanks for all that.
Your next "Rookie" question highlights the superiority of "bolt action trash" in all matters except getting off a quicker "one-two" in a close encounter. But then, the double's bullets will be more likely to tumble than will a fast twist BA bullet. History seems to indicate the old slow twists of tradition are adequate for brain shooting ...

500grains,

I would suggest that Messrs Rigby knew exactly what they were doing in going with the 416 caliber as the 416 Rigby. There were any number of 465/470/476/???? all the way up to twenty or thirty .500's. The ONLY rationale behind the excellent 470 Mbogo is the use of a bolt action instead of a mega-thousand dollar double rifle. Economics, my good man, economics. That is why it took so long to get a Rigby-based 45 calibre introduced; and why only Americans feel the need to shoot a 500gr .470 diameter bullet in 17 (mostly duplicative) iterations. Other than ego-stroking, why have both a 495 and 500A2? Answer: because we can. It is all good fun, but anyone can go to Africa with a 300magnum and a 458Lott and have more than enough rifle for everything. That said, I am in the process of assembling a 550 Magnum and trying to do a 500 on the 416 Rigby case.

regards,

Rich

Could it be that the slow twist double rifles should only be used with a lead-cored solid like the TBSH (Flat Nose) or Woodleigh FMJ (Round Nose)???

And of course, lead-cored softs like the Woodleigh Weldcore RNSP are always winners in 2150 fps double rifle loads.

Like Ruark said:
"Use enough gun and a short enough bullet, or get a fast twist."

quote:

Originally posted by Idaho Sharpshooter:
500grains,

I would suggest that Messrs Rigby knew exactly what they were doing in going with the 416 caliber as the 416 Rigby. There were any number of 465/470/476/???? all the way up to twenty or thirty .500's. The ONLY rationale behind the excellent 470 Mbogo is the use of a bolt action instead of a mega-thousand dollar double rifle. Economics, my good man, economics. That is why it took so long to get a Rigby-based 45 calibre introduced; and why only Americans feel the need to shoot a 500gr .470 diameter bullet in 17 (mostly duplicative) iterations. Other than ego-stroking, why have both a 495 and 500A2? Answer: because we can. It is all good fun, but anyone can go to Africa with a 300magnum and a 458Lott and have more than enough rifle for everything. That said, I am in the process of assembling a 550 Magnum and trying to do a 500 on the 416 Rigby case.

regards,

Rich

Rich,
recall this is all in fun.. and I am stating my opinions with equal assumption that I am correct as you are stating yours.

seems like you've both shot a bunch and have some firm opinions. Some of which may or may not be valid, or, in some cases, not so accurate.

one thing that you seem to repeat is "why"

the 450 Nitro's began it all 500gr at 2150
3 450 NE round
1 470 NE
3 475 NE round
1 465 NE

EIGHT rounds that all through a ~500gr bullet at ~2150... partly due to laws...

repetition doesn't seem to be a bad thing

For example, there were 2 major 475's ( 470 captick, 475AM) already exceeded the 470 NE, 35 years before dave made the 470mbogo. Therefore the idea that it's sole reason for existing has nothing to do with double rifles. and today, there's the capstick, AM, mbogo, and 470ar for exactly FOUR .475 shooting calibers... the british have 8 in that "range" for double guns

why so long for a rigby based 45?
here's a very brief HIGH LEVEL chronology
416 rigby
add a belt- neck it to 45
460 weatherby
neck that to 416
416 weatherby
neck it back to 45 and remove the belt (1995)
450 rigby... but we aware of these things
1: the "450 rigby" is an american round, by the guy in california (who bought rigby) who bought the NAME
2: rigby brass spent 40 YEARS of being unavailable, and people had to turn the belts off weatherby cases to make 416 rigby.
3: the 460 weatherby IS a 45caliber rigby wildcat.. with a belt scrapped into it. 60 years ago.

next, on 17 variations of the /475 diameter ... sir, that's 17 variations of 458 bullets, not .475 (there's not .470 diameter bullets, period) .. and if you did a quick spreadsheet of those 17 458 bullets, then lay out the price, you'd see it runs from 12¢ to 5bucks per...

i WISH there was a 12cent .475 jacketed bullet.

there's a SINGLE american major company that makes .475 conventional bullets.. and they aren't conventionalll swift...

there's a single major american .475 monometal bullet maker.. barnes...

Why the .495 and 500 asquare? that's EASY... the 405 can fit in a standard length action.. the 500 really cant .. and that's why... Why have anything larger than a 8x57? that's where ego comes in!! ::

Good on you building a 550 magnum... an amazing case and you won't waste your time with a 500xjeffe

Yes, there's nothing wrong with a lott.. and it's a fine stopping rifle...

but it's not the end of the world either... the 8x57 has killed EVERY thing on the planet... essentially the old successful BOLT gun round...

and it even has 3 variants, with 2 different bore sizes (318, 323, and rimmed)

jeffe

quote:

Originally posted by Andy:
2nd rookie question? Do any double rifle makers offer a quicker than std twist in a 470 or 500?

As always, Searcy to the rescue! You can commission just about anything with Butch Searcy, specifing your regulating load/velocity, etc., and I am sure he can accomodate a quicker twist rate since he gets his barrels from Pac-Nor who offer a very wide variety of twists.

Ya got me there jeff...all in good fun I admit. If I could just get some gunsmith to take the plunge; take my barrel and action, consisting of a Remington CF model of 1934 and Bauska 50 caliber barrel; and run a 470Mbogo reamer into it, finish up with a proper throat reamer about .538"OD, and present me with my 500Mbogo...I would be a happy camper. This is a subtle hint...hint, hint!!! They'd also need to deal with opening up the feedrails and tinkering a bit, but imagine the glory, fame and fortune that would follow such a man the rest of his life. No more snide comments behind his back about "puny, sub-half inch mosquito swatters", no more references to a more virile, manly cartridge duplicating the .500NE 3" in a boltgun. Nay, dare I say it (I dares!!) surpassing the .500's performance in a true African calibre!!

How's about that for an "...I double-dog dare you...?" to start your week off.

I call and raise...

regards,

Rich