Bored with same old 500A2 and tired old 500 Jeffery and .505 Gibbs "lightloads?"
Need a little variety?
The 500 Mbogo will do all that old stuff and some new tricks too.
The 500 Mbogo broadens the 500 Horizon.

.510-caliber bullets real and imaginary:

450-grainer: SD = .247
500-grainer: SD = .275
535-grainer: SD = .294
550-grainer: SD = .302
570-grainer: SD = .313
600-grainer: SD = .330
647-grainer: SD = .356
705-grainer: SD = .387
750-grainer: SD = .412
777-grainer: SD = .427 ( 0.111-pound bullet. That's a 9 Guage if rolled up into a ball. Thus much more effective than any 10-bore ball.)






The GSC 450-grain HV measured 0.512".
I pushed it through the Lee .510" sizer.
There goes the moly on the bands!
A 100% fill load of Hodgdon Benchmark in the 500 Mbogo is 114.0 grains, with COL as shown,
according to QuickLOAD:
2711 fps, 7346 ft.lbs.KE, and 59,882 psi.

The cast bullet is from a "tall block" NEI mould, #374, as cast in Lyman No.2 was .513".
After sizing to .510" and getting a 50-cal Hornady gas check, they average 777.3 grains.
A 100% fill load of H4831SC in the 500 Mbogo is 96.5 grains, with COL as shown, according to QuickLOAD:
1774 fps, 7365 ft.lbs.KE, and 36,387 psi.

Reckon I can beat a 45/70 with that .510/777-grain cast boolit?
Maybe I will have to try it in zinc if it kicks too hard at 777-grains.

Can't say I'm bored with any big bore yet. But I still like to see the pics and read the info.
It's pretty brave to go after the 45/70 like that. It is the best penetrator bar non after all. Beats the 460Wby with cast bullets going very slow blah blah blah...

PoppaW,
Thanks for the reply.
I especially enjoyed the "45/70 ... blah blah blah ..." part.
Yep, I think I have something that will beat a 45/70 for sure.
With a drop tube it should be possible to get those 777-grainers up to 1800 fps at less than 40K psi.
Should be the perfect wet newsprint stopper with hard lead.
With soft lead it might duplicate a high-velocity 9 gauge ball.

570-grain HV, FN, or TSX at 2400 fps will still be the "all purpose load."

450-grain HV at 2700 fps will make a nice 300-yard meat getter and varminter.

Very versatile this 500 Mbogo.

I am still puzzled as to why the 450-grain GSC had .512" bands.

Self: Dang! That is the prettiest cast boolitt I have ever seen!!!

Self: Double dang! That is the best 50-cal sporting cartridge ever!!!

Self: Thanks, Self! Attaboy Self!
Pat on back to Self.

Some might wonder at the wisdom of sizing the lead slug down to .510".

Well, it is like this:
The cartridge neck diameter is .532" with a .510" bullet loaded.
The chamber neck diameter is only .535" diameter.
Only .003" expansion room for bullet release.
I have a .512" sizer-luber from Lyman, but that would leave only .001" expansion room for bullet release in the neck.
I can size to .512", lube, and seat gas check first, in the Lyman lubrisizer, then size to .510" in the LEE sizer.

If the .510" 777-grain-FNGC won't shoot well, I will try to find a .511" sizer.

The Bubalus bubalis awaits ...

Jay,
Water buffalo?
This is not the "500 Bubalus!"
Are you saying the 500 Mbogo is "all wet?"
O.K., the "Fifty of Ought Eight" (FOOE) is my not-so-new baby, but still wet behind the ears.

The water buffalo at the Tennessee game farm will be devoted to .395 Tatanka with 310-grain S&H VeloHex Death Star of David.
The meat will be Kosher.

I do have to make sure the good 'ol Bubbas can truck in a Bubalus bubalis or two, and poke them with a sharp stick until they get un-domesticated enough to roam those 3000 acres. You know, get them to quit hanging around the barn.


[/QUOTE]

Yes, the namesake game needs to harvested. Cant wait for you to blood this cart with an Mbogo.

500 Mbogo is sooooo much cooler than the 500 A2

Other than nostalgia why would you chose the 500 Jeffery over the 500 AR and 500 Mbogo???

Hummmm...very nice. Wonder what a Gibbs case blown out slightly at the shoulder and the shoulder moved forward a bit would do??? An "improved Gibbs"

Surely someone has already "donnit". Pushing the CC to near 200 gr H2O would get you similar velocities with less pressure.

We're talking MAJOR thump here. Hahahahaha

Thanks for the info on the mould. I've been looking for a similar shaped bullet/weight in case I get my 50 cal project off the ground.

Luck on your projects.

Foobar,
NEI Hand Tools, yep, good moulds, good service.
They even had a .395/240-grain mould in their catalog. That is an FN-grease-grooved modernization of the old .395/230-grain bullet used in the 400 NFBP 3".

As to the .510/.505 Gibbs "Improved," I am sure that Clymer has that reamer in their catalog, and more than one version of it ... and more than one version of the supposed .505 Gibbs too.
I can remember comparing the differing specs on those. One should specify CIP specs for the .505 Gibbs and "improve" from there.

Phil Shoemaker got a .510/.505 Gibbs "Unimproved" rifle by accident once upon a time when his smith mistakenly used a .510 barrel and chambered it with a .505 Gibbs reamer. So I have read in Phil's writings, I usually read any of his stuff I find.

A .510/550-grain S&H VeloHexploder of SD .302 is an interesting concept. Even another 450-grainer would be interesting, especially if the bands come out actual .510" diameter!

However, no matter what bullet one shoots Tennessee pigs with, the pork chops will never be Kosher, tasty as they may be, when cooked "well done."

There's no "Rent-A-Rabbi" is rural Tennesee ...??

Can't pigs convert ...??

quote:

Can't pigs convert ...??

Of course they can!
They convert slop into BACON... mmmmmm bacon

I would have bet the ol' homestead on that one. Not sure if the additional colume would make much difference...maybe, MAYBE a mechanical advantange, but?????

I checked out NEI and found it...and I have a long list of mould makers when I get all the ducks lined up and walking in a relatively straight line.

A reamer can be made by Clymer or PT&G cheap enough, but I can rent a 505 reamer for 1/3 that price so it's just pleasant whiskey talk around the campfire.

Definitely BIG braggin' rights tho'..."I godda 50 cal Gibbs that shoots a XXXX at XXXXf/s...only one in existance.

Rip...Does QL calculate case H2O volume from a line drawing or cartridge design by any chance. I think I need to add that program to all my others.

Luck on your projects.

FOOBAR,
QuickLOAD will give you a case capacity in H2O gross by selecting from the cartridge case drop down menu.
Not all wildcats are included. 550 Magnum (Shirley) is there. Cool!
500 Mbogo? Not there.
That is "classified."

QuickLOAD is among the best of listings, seems as if they actually measured some real cases with representative brass before they tabulated the values.

QuickLOAD is much better than the gross underestimations of ammoguide.com, which uses some funky software to calculate the values as an easy/lazy way out.

You always need to measure your actual brass, varies by make as you know, to plug into QL. Always get the best data possible.

And furthermore:

My 500 Mbogo throat is .511" diameter freebore.
a dummy loaded with the .512" GSC HV 450-grainer would not even chamber in my rifle, until I had sized the bands down to .510".
I do like to seat them with a few bands in the freebore. Why waste case capacity?