Some fired primer pockets dirty, some shiny

[threeoh]

Hi all,

I have a bunch of .308 brass which is all 4 or 5 times fired. How dirty or clean is stays though is really confusing me...

Some of the primers pockets are black, some of them are shiny as being brand new though. Same for the insides, some just seem to stay shiny and others get the brown layer build up.

I haven't accidentally dropped a few new cases either, the clean ones are definitely fired the same.

Explanation?

[thebear]

I think you will find it is a combination of the primers, the flash hole in the case and the primer pocket. I get the same thing for the various calibres I load for.

You have to remember that the primer compound is wet when first placed in the cup and the anvil inserted straight after. The anvil might not be perfectly centred or the flag hole might not be perfect. I see this a lot when I reload pistol rounds as I do about 200 a time. I always however clean the primer pockets.

The only sign that you should look for is soot around the fired primer as this tells you that the pocket is not sealing the primer properly.

[Lorgar]

Can't say I've ever looked into it but mine is the same.

My current 7mm brass is all 5-6 times shot and some pockets are black, some are pristine.

They all shoot the same...

[ghunther]

If you're worried a primer pocket reamer is about $25 bucks.

Cleaning the pockets every few shots just ensures your primer seating depth is consistent.

[Lyam]

Cleaning the pockets every few shots just ensures your primer seating depth is consistent.

IMO, 2 cents, usual disclaimer...

Cleaning the primer pockets is nice, but that's about it.

Some guys say you should do it regularly to "reclaim" that 0.001" of primer depth or whatever, but c'mon... I haven't any evidence of it giving any sort of improvement at all.

Focusing on things like consistent powder charges, neck tension, COAL etc. are all going to give much more noticeable gains.

If someone can show me evidence of a few thou here or there of primer seating depth making a difference I'm all ears, but I doubt it.

[Lyam]

Adding to the above, I'm obviously only talking about when the primer is seated correctly.

If the pocket is deformed or the primer is set too low, or obstructed and too high or something is otherwise 'wrong' that's a different story.

[threeoh]

If you're worried a primer pocket reamer is about $25 bucks.

I'm gunna give one a go.

I'll mark a few cases and clean them, then track which ones get dirty again and see if I can make any sense of it.