How important is primer pocket/flash hole prep?

Bill I happen to have that exact same Harbor Freight work bench...my press is on the right side...I also have a set of the heavy duty shelves to hold bullets, boxes of loaded ammo, powder and "stuff"
About 10 years ago my wife bought me this "Whelen" bench at Costco. It's solid as a rock and quite suited to the task. Look closely and you'll see I was cooking up some "Garand Food" last night!
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If you weight sort your brass you will want to deburr the flash holes and cut the primer pockets to depth . I like to fire my brass 1 time size it cut it to length, cut the primer pockets to a standard depth, deburr the flash holes , then weight sort it . You can take some brass and weigh it right out of the box and sort it into groups load it , fire it then do the prep and reweigh it you will have more pieces of the same weight after doing it this way .
 
In my reloading experiences thus far I've never messed around with deburring flash holes, specially cleaning or uniforming or in any way correcting primer pockets or flash holes...

Am I missing out on a very important practice? How big of a difference does this make for es numbers and accuracy? Please share if you do this, and please I'd love to see some "before and after" data regarding consistency of performance.

thanks.
Shhh... keep this real quiet. So far the chrono and targets have not noticed I never attend to the primer pockets! Seriously, with quality brass, it is a waste of time IMO as it makes no difference in the consistency of down range results. If you enjoy it carry on, it's not hurting anything.
 
I have done it since the 80s, and I like the "idea" of it. I went to quality brass and don't have to touch either, so now only on the cheaper/factory stuff. Of the two, the "only" one I worry about, is the flash hole, I have seen smaller groups from doing that, as much as a 1/2" too. Cleaning? I always scrape the carbon out, just so it can't possibly absorb moisture. It probably can't anyhow, because of the tight fit, but it makes me feel better. :)
 
I've found uniforming primer pockets is just for fun and doesn't really do anything. If you're using different varieties of brass, uniforming the flash hole and deburring had a measurable gain in accuracy on the cheaper brass
 
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I have seen an improvement in the bulk brass I used to use back in the day with a skinny wallet. Finally got to using Lapua and Norma brass and discovered through testing I didn't need it. So the question is, I think, "what's your time worth?". Do you need to use lower end brass to save $$$ or spend the $$$ and save the time? If so, I have seen about a 10% decrease in group size by using Sinclair flash hole deburr tool. I cant see any difference (and have tested it) with the higher end brass. Lazy now and out of that business:)!
 
IMHO Consistency is the key to consistent accuracy. If what I reload is consistent, same process, then next issue is shooter consistency. So, I deburr and uniform primer pockets as part of my reloading process. if nothing else, it can't hurt!,
 
I do deburr the flash hole and uniform the primer pockets on new brass. I have no evidence that it makes a difference. But I have seen large burrs on the inside of the flash hole a couple times. I do it because why not, it only takes a couple extra seconds and I can't imagine it hurts anything as long as you don't screw it up somehow.
Completely agree, it takes a few minutes, so why not. Does it make any difference?I can't say but if it gives the shooter more confidence in the end product, do it. If not, don't. My personal experience is the greatest effect on the ammunition os the shooter. With all my efforts, occasionally I mess up a shot.
 
I like what L. Kilbourn the inventor of the K-hornet used to do with bench rest brass. He loaded it and
then shot it. Any brass that went out of the tight groups got separated and he used them for practice
or varmint hunting.
Zeke
 
I've never uniformed primer pockets but I do uniform and debur flash holes. I use the Lyman tool with the tapered bushing on new brass that has been trimmed to the same length. I take it off the handle and chuck it in my drill. Takes about 10 seconds a piece and only has to be done once so it's worth it to me. I've always done it and never had a problem achieving consistent accuracy and velocity so There's no reason to stop now.
 
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