Primer pockets….

[zeke]

Originally Posted by HKGuns

I have sub 1/2 minute groups with dirty primer pockets with no discernible difference between clean and dirty.

I also have numerous professional shooters who wouldn’t win matches if it mattered. Many, not all don’t clean primer pockets either.

I’m not forcing anyone to do anything. I’m asking for evidence based data and of course there is none. It’s simply what someone heard, just like breaking in a barrel or neck sizing brass which is also a mistake.

You have provided absolutely no evidence what so ever, while asking for evidence. Granted i don't shoot near as much as i used to, but 1/2 moa groups were pretty common from an accurate rifle.


I choose to clean my primer pockets from long experience in doing so. I also choose to break in a rifle barrel or neck size when i deem it appropriate. Having done all of them multiple times and seeing the benefits first hand.

[Unclenick]

It shouldn't be hard to resolve the question. I believe Dillon claims to have done a lot of testing and found no difference in the ammunition quality, but that would be based on a comparison to ammo with clean primer pockets loaded on their equipment. That result may differ from what someone loading one at a time for benchrest matches finds.

This article on measuring primer blast waves shows the extreme spread in primer performance is surprisingly large, exceeding 20% with Federal 210M primers, and they did not have the highest SD in the table on page two. So it makes sense that so much variation in the primers themselves will cover up ignition variation due to old primer residue. However, reading all of page 3, the prospect of reducing that variation by weight sorting of primers may make it possible to tell a clean primer pocket from a dirty one with sorted primers, with the difference being in velocity variation of the finished load. Velocity variation, especially at shorter ranges, often is no predictor of group size by itself, but on the other hand, reducing it for a given load certainly won't hurt anything and can be helpful with long-range vertical spread.

[HKGuns]

Originally Posted by zeke

You have provided absolutely no evidence what so ever, while asking for evidence. Granted i don't shoot near as much as i used to, but 1/2 moa groups were pretty common from an accurate rifle.


I choose to clean my primer pockets from long experience in doing so. I also choose to break in a rifle barrel or neck size when i deem it appropriate. Having done all of them multiple times and seeing the benefits first hand.

Waste all the time you have cleaning primer pockets.

I went no.

[Jim Watson]

Warren Page, one of the fathers of modern benchrest shooting, said he went a whole competitive season without cleaning primer pockets and saw no difference in groups.
He said it was tough, he was so accustomed to the routine.

Now if you are talking about long term barrel erosion from leftover primer mix added to each shot's primer mix, maybe you ought to clean them.

[zeke]

https://youtu.be/fHV6Q-SCrAA

and yet i still clean them