wondering if anyone has wildcatted the 416 rigby to .510 caliber. It should be close to the 500 A2 performance

Yes. At least three variations exist here due to AR tinkerers. I have one, the 510 KX. It is the .510 Wells Express, minus that irritating belt.
The selling point: it uses .510 Wells dies.

Rich
DRSS

500 Mbogo - full length rigby
510 KX - full length rigby
505 rigby - ask RDB (no other data)
500 AccRel- shortened rigby, 3.4 oal, fits in standard length action
all the above do 600gr at 2300, or better


500 MDM - RUM based
.500 based bullets

frankly, the AccRel is setup for standard actions and throated to all using milsurp bullets, if you like, as well as 535, 570, and 600 gr bullets

oh yeah, 500 mbogo. I should have realized that. does it have enough shoulder to headspace without problems?

We've been shooting a few of them since the late '90s in a .505 version built on a full size .416 Rigby (or 450 Dakota) case blown out.

Pleanty of shoulder on the .505 or .510 versions.

More here:
http://pistolsmith.blogspot.com/


But the better history lesson comes from IdahoSS:

"John Buhmiller built a 500/378Wbee first in 1956-57, and in 1959 or 1960 built several 45 and 475 and 50 caliber rifles using the 416 Rigby basic case. I (Rich aka ISS) visited John Buhmiller in his shop three or four times before his death. He initially built his big bores on Wbee brass, but due some "misunderstandings" he switched to the Rigby case very early on. That is a matter of record, not just my statements here. The fact that I owned a 450 based on the Rigby case built by Buhmiller is more convincing...."

gohip
there's certainly enough shoulder there, and headspace appears to be positive.

decide what recoil you want and what action you plan to use, and slip one in there

If I were building a new one today, I would use Jeffe's KISS principle and do a 500 AccRel. RUM brass is plentiful and cheap, and all the leg work has been done for you here.

Rich

Looks like 4 basic choices up front depending on the labor you are willing to deal with for loading, the caliber (.500/.505/.510), brass and die expense and the action size you are going to use/want.

.500 on a Rigby case

Fire form .416 Rigby 2.90" case and load.
Or just load the 450 Dakota brass and shoot it.
$2.00 to $2.50 each depending on volume. Reamer prints available for either .416 Rigby or .450 Dakota as basic brass from JGS.



.500 on a chopped Rigby case
aka .500 AccRel

Or QC head stamped brass @ 3.44 each.

416 Rigby, Trimmed to 2.65, necked up, loaded for fireforming, 500 AccRel



.500 on a stretched Rigby case

aka .500 Mbogo on 3.00" basic brass.
Start with unformed basic .416 brass if you can find it. Or QC head stamped brass @ 3.44 each.

chopped? yeppers...
chopped to fit in a standard length action -- there's no troubles making the cases, cheap if you start with hornady 416 rigby ... right at 130gr h20, (close to a 495a2 in capacity) .. and it will meet/bet the 500jeffe (classic loading) and 500 nitro ...

and mine is throated to allow use of milsurp bullets without "in the lands" pressure spikes .. and the only one that fits nicely on a standard length action that most any gunny can make it

The more I get to read about the .500 AR, the tempted I get to have one made up.

What capacity does Duane Wiebes magnum length assemblies take of the .500AR??.

its about 130gr capacity... and thank you for thinking you like it.. 495 a2 bottom should work great, but i don't "know" that for certain ... nor do i know which of Duane's would work right