chamber throat leading, revolver

Ran across an older thread of last 15 years on a forum, and i cant remember as I was perusing my phone browser duiring a thinking session. 

The thread/gospel session,  dictated that ALL leading in a revolvers chamber and throat was caused by the bullet ALLOY  being TOO HARD for the chamber pressure being used. 

Now I have only used 3 cast bullets in a handgun, speer swagged SWC and HBWC.   And commercially cast swc-hp of 20:1 alloy and lubed with carnauba red. 

all of them leaded in the alloy.  Regardless of what actual chamber pressure was. I was using the whole gamut of powder charge, standard 38 special loads, +p loads, even Skeltons pet loads for 38 special, and 38 special magnum loads.. 

ALL of them caused leading in the chambers, and throats,, 

SO at what point is the hardness actually going to be beaten by chamber pressure?

Slug your barrel, and then check the chamber throat diameter. Throats may be too small.

Jerry Keefer was such a loss...
Along with cylinder throat sizing the forcing cone also contributes to leading.  Taylor throating will also help to take care of this issue.

20-1 is 10 BHN.  To soft. Standard for cast is 15 BHN.

243winxb wrote:20-1 is 10 BHN.  To soft. Standard for cast is 15 BHN.

so even though advertised for magnum ammo, still too soft?

I learned using old  Lyman info. Works for me.

https://archive.org/details/LymanReloadingHandbook48thEdition2002Ocr/page/n104/mode/1up

https://www.weatherby.dk/bhn.htm