Converting GP11

[mwells72774]

Swiss Berdan primer diameter: .217"
Large Rifle Boxer primer diameter: .210"
Difference: .007"
Thickness of material required to reduce diameter by .007" = .0035"
Average human hair thickness: .004"

Here is another approach -

https://www.milsurps.com/images/impo.../33zbjwn-1.jpg

I hadn't ever measured, my guess was way off seems.

Can you go into detail on step 3 a little. I'm trying to figure out how you went about shrinking the primer pocket.

[Parashooter]

See Berdan to Boxer Conversion Method in Handloading Forum for details. Be sure to follow the link to Mr. Chandler's post for more information - http://web.archive.org/web/200901091...er/primer.html

[mwells72774]

See Berdan to Boxer Conversion Method in Handloading Forum for details. Be sure to follow the link to Mr. Chandler's post for more information - http://web.archive.org/web/200901091...er/primer.html

I guess I don't understand how the ball bearing comes in the play. Does it swedge the primer pocket down to a smaller diameter? I guess I'll just give it a try and see what it does

[Parashooter]

Pressure on the ball bearing displaces brass from the upper periphery of the primer pocket, reducing its diameter enough to retain the .210" Boxer primer securely.

[mwells72774]

Pressure on the ball bearing displaces brass from the upper periphery of the primer pocket, reducing its diameter enough to retain the .210" Boxer primer securely.

Did tried it... far easier

[Parashooter]

By the way, what bullet and propellant load are you using in your reworked cases?

"Once I'd made up a dozen cases, I loaded and fired 150-grain bullets [Win. FMJ] with charges of WC852 from 43 to 55 grains, then reloaded and fired one case 7 times with the stiff 55-grain load."