357 Bain and Davis Headspace

[jensonev]

Conventional wisdom says headspace behind the rim should be between .008-.012". In Lee Martin's article, he mentions setting the headspace on his blackhawk, but not the spec.
If he happens to see this, I'd appreciate a little enlightenment, thanks.

[45MAN]

FYI, JACK HUNTINGTON SAYS THAT HIS TECHNOLOGY FOR NECKED DOWN REVOLVER CARTRIDGES WOULD MAKE THE 357 B&D VIABLE IN A REVOLVER.

[Encore64]

I'm not sure who's conventional wisdom that is, but I generally prefer .003-.005". Of course, it's not really headspace. It's just the gap between the rim and aft window wall.

A few tout the ability to chamber ammo where the primer was seated too high if more gap is left. That makes about as much sense as chambering loose so dirty ammo will fit...

[AxeHandle]

For people that like such things, Gary Reeder does revolver stuff like necked down 41 to 357, 44 to 41, and 454 to 44... He sells die sets and provides loading data too. I'm watching for a cherry used stainless 9mm/357 Blackhawk myself. Plan to send the gun to Gary to have the 9mm cylinder converted to 356 GNR

Go here and page down to see all the offerings.
reedercustomguns.com/information/gnr_cartridges.htm

[jensonev]

Jun 15, 2024 10:12:39 GMT -5 Encore64 said:

I generally prefer .003-.005". Of course, it's not really headspace

The particular cylinder I have is .004", I was just curious if Mr. Martin made his tighter and whether he attributed that as another reason he avoided case setback. Seems tight chamber-sizing die dimensions and cleaning free of oil is the biggest contributor to avoiding it.
The numbers I said were just what SAAMI states as minimum and maximum for space between the 44 Mag rim and recoil shield, but real world doesn't tend to follow those.

[jensonev]

Jun 15, 2024 8:02:27 GMT -5 45MAN said:

FYI, JACK HUNTINGTON SAYS THAT HIS TECHNOLOGY... WOULD MAKE THE 357 B&D VIABLE IN A REVOLVER.

I believe him too. His work is immaculate.
Did he suggest what it was?

[45MAN]

Jun 15, 2024 11:05:47 GMT -5 jensonev said:

Jun 15, 2024 8:02:27 GMT -5 45MAN said:

FYI, JACK HUNTINGTON SAYS THAT HIS TECHNOLOGY... WOULD MAKE THE 357 B&D VIABLE IN A REVOLVER.

I believe him too. His work is immaculate.
Did he suggest what it was?

AS I STATED IN A RECENT 218 BEE REVOLVER THREAD, HE HAS A PROCESS BUT HE IS TIGHT LIPPED ABOUT THE PROPRIETARY PROCESS.

[jensonev]

Jun 15, 2024 11:08:35 GMT -5 45MAN said:

Jun 15, 2024 11:05:47 GMT -5 jensonev said:

I believe him too. His work is immaculate.
Did he suggest what it was?

... BUT HE IS TIGHT LIPPED ABOUT THE PROPRIETARY PROCESS.

Which is fair, it's the man's livelihood and he built a better mouse trap.

[Lee Martin]

The Bain & Davis headspaces off the rim. What I think you're asking about is clearance between the rim face and recoil shield. I can't remember what we did on our B&D's, but I'll check when I get home. BTW, that isn't a critical spec for the round. Anything within reason, such as factory gaps, work fine. You don't want it too tight or the slightest amount of residue on the back of the cylinder can cause bind.

-Lee
www.singleactions.com
"Chasing perfection five shots at a time"

[jensonev]

Jun 16, 2024 20:36:22 GMT -5 Lee Martin said:

Anything within reason, such as factory gaps, work fine.

-Lee
www.singleactions.com
"Chasing perfection five shots at a time"

Thanks, it was something I'd read in your article, but was struggling to imagine if that related at all to avoiding setback.
I know your dies are set very close to the chamber dimensions, do you bump the shoulders back a few thousandths or is that even necessary?

[Lee Martin]

Just size the case as you normally would. It'll push the shoulder back a little. Unlike bottle necks with very sharp shoulders, the amount of bump isn't as critical with the Bain & Davis.

-Lee
www.singleactions.com
"Chasing perfection five shots at a time"

[jensonev]

Thanks for the responses all, hope you gents stay cool out there.