How important is primer pocket/flash hole prep?

[Laelkhunter]

Maybe I shouldn't say this publicly, might get flogged... But I've never really done anything to mine, never felt like I was missing out.

Me too. Other than visually inspecting the primer pocket and flash hole for debris such as tumbling media, I just load them up.

 

[JAYgs8163]

I have not had to with Lapua and Peterson brass. I did both to some Hornady brass that I used for making 6.5-06AI brass. It shot very well, but I did not do a comparative test.

The last 2 boxes of 6.5 CM Lapua brass I got needed flash holes uniformed. I was told these are not drilled anymore by Lapua but stamped/pressed through.

 

[338 dude]

 

[Wiley J]

Got me thinking so I tried this. Got 20 new cases and full length resized. Did primer pocket /flash hole in 10. Loaded as per usual. Shot at 100 yards alternating between prepped and unprepped, each type onto a differ target.
Result. No discernible difference.
6.5 Cr. 143gn ELD-x. Sub 3/8 groups.
Conclusion. I ain't gonna bother no more.

 

[MoaFlat]

Got me thinking so I tried this. Got 20 new cases and full length resized. Did primer pocket /flash hole in 10. Loaded as per usual. Shot at 100 yards alternating between prepped and unprepped, each type onto a differ target.
Result. No discernible difference.
6.5 Cr. 143gn ELD-x. Sub 3/8 groups.
Conclusion. I ain't gonna bother no more.

Check your SDs with and without flash hole reaming... surprised us.

 

[JAYgs8163]

I don't think anyone will see a big difference in groupings at 100 yards, 200 yards or even 300. When you take the time to get a consistently lower SDs though the results are going to be reflected in your long range shooting IMO. When you take the additional time and pay attention toALL the little things they all add up to making BIG differences In overall performance. I've got most of my loads in low single digit SDs and I truly think it's because of the extra attention to the small details. Got these loads at a 3.6 SD.

 

[Savage 12BVSS]

It's a great bench for the money I have no problems with it whatsoever there are a lot of other areas I would like to improve on but my bench would be dead last

Thank You for clarifying about the lapua brass being punched to save money and speed production. It only confirms that they all need to be checked, prepped, and deburred regardless of brand or price. You do have a very nice bench and set-up as well. Dave

 

[Tree Farmer]

Check your SDs with and without flash hole reaming... surprised us.

 

[Tree Farmer]

I think that's the point. When I started reloading I just screwed in the dies and added powder/bullets. I didn't even know how to measure shoulder bump, bullet jump, ect. and I had loads that were sub moa @ 100 yds. But I doubt those loads could hold moa beyond 200 yds.

 

[Wiley J]

I'm definitely holding sub moa at 600 yards. Haven't been any where that I can check further. But to be honest most of the country I hunt rarely calls for shots more than 300 yds. Heavy timber and steep.

 

[Tree Farmer]

That's my problem. I can't shoot very well, so I compensate by being anal about my handloads. I'd probably be better served by spending more time behind a rifle and less time at the reloading bench.

 

[cape cove]

Got me thinking so I tried this. Got 20 new cases and full length resized. Did primer pocket /flash hole in 10. Loaded as per usual. Shot at 100 yards alternating between prepped and unprepped, each type onto a differ target.
Result. No discernible difference.
6.5 Cr. 143gn ELD-x. Sub 3/8 groups.
Conclusion. I ain't gonna bother no more.

I respect your test but I believe the best way to conduct a test such as this would be to debur 10 cases then select 10 cases with a bur inside the flash hole.(borescope) Maybe the 10 cases you selected were good or most were. When I debur the cheaper makes of brass that I use many of them would be good to go, but others are real bad. It only takes one to ruin your day. JMO
PS I assume your are testing deburring flash holes vs non debur flash holes.

 

[Andrew Cowling]

I have always done mine so that the cases all start out the same. Consistancy is the game.

 

[bushmotornv]

I have no doubt there'd be no detrimental effect in doing this sort of thing, just looking for some experiences confirming improvement with hard data. Thanks for the feedback. I do think I'll start doing this on that same basis, it can't make anything worse and just might make it better. On the flip side if we eliminate all possible culprits other than ourselves when the guns and ammo aren't shooting the way we want we might just be humbled a bit too much so maybe I'll keep leaving them alone! In all seriousness, what tools for these jobs would you all recommend?

K&M,all the way. With the exception of primer pocket uniforming,it's all once and done. The primer pocket uniformer cleans the carbon out of pocket nicely as well as brass that always flows into the pocket every firing. And,K&M tools are very reasonably priced.JMHO