Wildcat idea: 500 S&W case + .510 barrel + 50 BMG bullets

Crosshair · March 25, 2018, 08:47 PM

I can't have been the first person to think of this for a 510 Whisper type of cartridge, so someone tell me if this has already been done so I can just copy them.

Take a 500 S&W case and seat a 50 BMG bullet into it. Bam, 30-40-ish grains of powder capacity. Whisper territory.

Of course the 500 S&W uses a 0.500" bore, so you would need a custom 0.510" barrel with a longer throat to allow those longer bullets. Not sure how to specify the throat or what a good value would be.

I was thinking about using the Bauska BBK-02 Magnum action I have for this. I made up a dummy cartridge and with the BMG bullet it will feed from the magazine. The rim is slightly smaller, 0.556" for the 500 vs 0.588" for the 338 Lapua. A difference of 0.032", but the extractor seems to grip it just fine.

So, lets see what everyone else thinks about this.

**Mike Irwin** · March 26, 2018, 05:52 AM

Would the case be long enough to handle that large a bullet and still leave you with any powder room?

I think most .50 projectiles for the BMG are about 2 inches long. Even with minimum seating that would only leave an inch or a bit more for powder...

I think you'd be really hard pressed to make this work, but it is quite intriguing.

I know the .510 Whisper uses .338 Lapua cases that have been cut back to just shy of 2 inches... But, it has to be necked to seat the bullet, which means you get a bit more powder capacity.

taylorce1 · March 26, 2018, 07:21 AM

I've read that the .500 case doesn't work well from stack magazines, something about the rim getting locked up with the extractor.

tobnpr · March 26, 2018, 06:50 PM

Freewheeling here....subsonic isn't my "thing" (though I am working on a .45-70 for these:
https://www.lehighdefense.com/collec...ant=3410532292)

But why not neck-up a .505 Gibbs a teeny bit? With 750's, and a slow-burning powder?
That action would be perfect for it.

laytonj1 · March 26, 2018, 07:11 PM

Underwood makes ammo for the 500 S&W with 700 gr. bullets at 1200 fps.
I believe Ranger Rick offers 700 gr. bullets.
They are flat nose so I don't know how well they will feed in different actions.

Jim

**Mike Irwin** · March 27, 2018, 05:46 AM

"Underwood makes ammo for the 500 S&W with 700 gr. bullets at 1200 fps."

Those are basically flying thermoses. The bullets have very little taper. Because of that, they're significantly shorter than a .50 BMG bullet.

ruggyh · March 27, 2018, 08:57 AM

Since rimmed cases are problematic when used in magazine why not use a rimless case like the 500 Auto Max

or better yet just get a AR500 and load subsonic

be safe
Ruggy

**Mike Irwin** · March 27, 2018, 09:03 AM

Many rimmed cartridges have been used in magazine-fed semi-automatics over the years.

Rimlock is a fairly rare happening and every case I've ever seen has been the result of a damaged magazine or operator error in loading the magazine.

tobnpr · March 27, 2018, 06:17 PM

Quote:

Many rimmed cartridges have been used in magazine-fed semi-automatics over the years

Yep
Including my fave the 54r. Dragunov, PSL, SV-98 and the modern Vepr- all mag fed. Most collectors also are familiar with the SVT-40 autoloader.

**Mike Irwin** · March 28, 2018, 05:59 AM

Not just rifles, either...

Colt & Smith & Wesson .38 Special target semi-autos.

LAR Grizzly .357 Magnum.

Desert Eagle .357, .41, and .44 magnums

Dozens, if not hundreds, of different .22 LR chambered semi-autos.

And let's not forget the British Bren gun, one of the most successful and effective light machine guns of all time.

March 25, 2018, 08:47 PM	#1
Crosshair Senior Member Join Date: December 16, 2004 Location: Grand Forks, ND Posts: 5,333	Wildcat idea: 500 S&W case + .510 barrel + 50 BMG bullets I can't have been the first person to think of this for a 510 Whisper type of cartridge, so someone tell me if this has already been done so I can just copy them. Take a 500 S&W case and seat a 50 BMG bullet into it. Bam, 30-40-ish grains of powder capacity. Whisper territory. Of course the 500 S&W uses a 0.500" bore, so you would need a custom 0.510" barrel with a longer throat to allow those longer bullets. Not sure how to specify the throat or what a good value would be. I was thinking about using the Bauska BBK-02 Magnum action I have for this. I made up a dummy cartridge and with the BMG bullet it will feed from the magazine. The rim is slightly smaller, 0.556" for the 500 vs 0.588" for the 338 Lapua. A difference of 0.032", but the extractor seems to grip it just fine. So, lets see what everyone else thinks about this. __________________ I don't carry a gun to go looking for trouble, I carry a gun in case trouble finds me.

March 26, 2018, 05:52 AM	#2
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,388	Would the case be long enough to handle that large a bullet and still leave you with any powder room? I think most .50 projectiles for the BMG are about 2 inches long. Even with minimum seating that would only leave an inch or a bit more for powder... I think you'd be really hard pressed to make this work, but it is quite intriguing. I know the .510 Whisper uses .338 Lapua cases that have been cut back to just shy of 2 inches... But, it has to be necked to seat the bullet, which means you get a bit more powder capacity. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

March 26, 2018, 07:21 AM	#3
taylorce1 Senior Member Join Date: November 18, 2005 Location: On the Santa Fe Trail Posts: 8,245	I've read that the .500 case doesn't work well from stack magazines, something about the rim getting locked up with the extractor. __________________ NRA Life Member

March 26, 2018, 06:50 PM	#4
tobnpr Senior Member Join Date: August 1, 2010 Location: Tampa Bay Posts: 4,556	Freewheeling here....subsonic isn't my "thing" (though I am working on a .45-70 for these: https://www.lehighdefense.com/collec...ant=3410532292) But why not neck-up a .505 Gibbs a teeny bit? With 750's, and a slow-burning powder? That action would be perfect for it. __________________ Remington 700/Savage Rebarreling /Action Blueprinting 07 FFL /Mosin-Nagant Custom Shop/Bent Bolts Genuine Cerakote Applicator www.biggorillagunworks.com

March 26, 2018, 07:11 PM	#5
laytonj1 Senior Member Join Date: June 1, 2005 Posts: 4,443	Underwood makes ammo for the 500 S&W with 700 gr. bullets at 1200 fps. I believe Ranger Rick offers 700 gr. bullets. They are flat nose so I don't know how well they will feed in different actions. Jim Last edited by laytonj1; March 26, 2018 at 07:17 PM.

March 27, 2018, 05:46 AM	#6
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,388	"Underwood makes ammo for the 500 S&W with 700 gr. bullets at 1200 fps." Those are basically flying thermoses. The bullets have very little taper. Because of that, they're significantly shorter than a .50 BMG bullet. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

March 27, 2018, 08:57 AM	#7
ruggyh Member Join Date: February 1, 2013 Posts: 73	Since rimmed cases are problematic when used in magazine why not use a rimless case like the 500 Auto Max or better yet just get a AR500 and load subsonic be safe Ruggy

March 27, 2018, 09:03 AM	#8
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,388	Many rimmed cartridges have been used in magazine-fed semi-automatics over the years. Rimlock is a fairly rare happening and every case I've ever seen has been the result of a damaged magazine or operator error in loading the magazine. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

March 28, 2018, 05:59 AM	#10
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,388	Not just rifles, either... Colt & Smith & Wesson .38 Special target semi-autos. LAR Grizzly .357 Magnum. Desert Eagle .357, .41, and .44 magnums Dozens, if not hundreds, of different .22 LR chambered semi-autos. And let's not forget the British Bren gun, one of the most successful and effective light machine guns of all time. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.