The Firearms Forum banner

21 - 26 of 26 Posts

·
Registered
Joined
·
7,763 Posts
You've lost me on that one. They make a go/no go gauge for primer pockets? That's something that I've never heard of before.

I'm sticking with a light charge or not enough crimp.
If the pocket is loose, as the firing occurs, high pressure gas passes by it causing the blackening at the bottom and slightly on the edge of the case bottom.

Primer Pocket and Mouth-Neck Gages.jpg
 

·
Super Moderator
Joined
·
25,649 Posts
If the pocket is loose, as the firing occurs, high pressure gas passes by it causing the blackening at the bottom and slightly on the edge of the case bottom.
If the pocket is loose, as the firing occurs, high pressure gas passes by it causing the blackening at the bottom and slightly on the edge of the case bottom.

View attachment 233782
Well I'll be. I did not know about these. But then, I don't swage pockets, I ream them.
 

·
Registered
Joined
·
109 Posts
Discussion Starter #23
I tried this formula again today.

This time I used a CCI 550 primer.

The burn went away.
Recoil seemed to increase a little.

Strange.
 

·
Registered
Joined
·
1,370 Posts
If brass is starting to get hard & in need of annealing the sides of the brass won't expand to seal and some times crack. The burn marks is where the concentration of hot gases flow out around the brass.
 

·
Registered
Joined
·
10,065 Posts
The most common thing that causes external case walls to partially blacken is a load so mild that the brass case does not expand sufficiently to act as a good gasket to the hot gases.

The bass case is more than just a pretty holder of the powder and bullet. Its job is to seal the chamber during firing. If the pressures are too low then that will only partially happen and black soot will form on the front end of the case. The load the poster called out is a starting load (minimal pressure load). My advice is to make up a load close to a mid load (Never exceed the listed Max load). Try that load and the blackening of the front part of the case should stop or at least decrease. I see this all the time in my loads for 44 Mag and most certainly on 45LC loads. But a loose chamber can cause this as well, as the expanded fit in the loose chamber may reduce the adequacy of the case sealing. Even an inadequate crimp might cause it too as the bullet escapes too soon and the pressures are too low to swell the brass case sufficiently.

The bottom line is increase the load level. The blackening hurts nothing but better accuracy may be achieved with a mid level load rather than a starting load.

LDBennett
 
21 - 26 of 26 Posts
Top