Is uniforming primer pockets for functional or accuracy.

[Webster]

I pretty much do the same thing. Uniform my primer pockets and use my co-ax press too set the primer to get a consistent seating depth for a .002 crush.

Question for you: I use the same uniforming tool to clean the pockets and find I get a little bit of brass shavings and a shinny pocket. This indicates to me that after firing, the bottom of pocket moved due to the pressure. Have you found this to be so too?

I firing stiff loads can make the primers so loose they fall out of corse the pocket dimensions are changing.

 

[danny]

I pretty much do the same thing. Uniform my primer pockets and use my co-ax press too set the primer to get a consistent seating depth for a .002 crush.

Question for you: I use the same uniforming tool to clean the pockets and find I get a little bit of brass shavings and a shinny pocket. This indicates to me that after firing, the bottom of pocket moved due to the pressure. Have you found this to be so too?

Read my reply below your original post. That is two of us, at least, that find that the primer pocket dimensions can change, and probably do change upon each firing.

Danny

 

[danny]

I know that uniform cases in every aspect is the goal. But I have never had a piece of brass that required modifications of the primer pocket in any way. I dont use crimped brass. So because I have never, should I be checking and uniforming pockets for reasons other than functional reasons.

Primer Pocket Uniformers do nothing to or for crimped military brass.

Danny

 

[mikecr]

Pocket changing (dimension/rate) depends on a lot of things.
Likely a little different for each of us, with each chamber & load.

 

[memilanuk]

Question for you: I use the same uniforming tool to clean the pockets and find I get a little bit of brass shavings and a shinny pocket. This indicates to me that after firing, the bottom of pocket moved due to the pressure. Have you found this to be so too?

I've noticed in the past when shooting Winchester brass that the first pass with a primer pocket uniformer (on virgin brass) would typically only cut in the corners of the pocket. On the next couple firings, the cutter would touch (clean up) a spot right around the flash hole. After that, the two areas getting cut would grow closer together, and eventually, about the time the brass was due for the recycle bin, they'd finally touch and the uniformer would hit the entire bottom of the pocket.

More recently, on Lapua brass... I've had some in .223 that I get a little more contact each time - not quite as distinct of a pattern as with the Winchester, though. On my .308 Palma brass... a lot of it the cutter never even scrapes the bottom, even with multiple 'warm' loads thru 'em.

Definitely interesting.

 

[danny]

I know that uniform cases in every aspect is the goal. But I have never had a piece of brass that required modifications of the primer pocket in any way. I dont use crimped brass. So because I have never, should I be checking and uniforming pockets for reasons other than functional reasons.

The reason why you never had a piece of brass where the primer pocket needed modification is because:
A) You never used brass that had crimped primers installed.
B) You have probably never uniformed flash holes (I don't).
C) You have never put a Primer Pocket Uniformer in a piece of brass to see that it will remove material, or have never measured any pockets.

Danny

 

[rsmithsr50]

try buying a simple tool like a Sinclair carbide uniform/depth tool.
you have to read the tool title carefully

I think it would be hard to improve a primer pocket with some of the tools that are sold for that purpose. I simply clean out the residue.

 

[AJC]

The reason why you never had a piece of brass where the primer pocket needed modification is because:
A) You never used brass that had crimped primers installed.
B) You have probably never uniformed flash holes (I don't).
C) You have never put a Primer Pocket Uniformer in a piece of brass to see that it will remove material, or have never measured any pockets.

Danny

B and C. I started as simple as possible and am evaluating details as I get more experience. This seems very low cost but I have no data to evaluate the return on effort.

 

[Coyotefurharvester]

I had purchased a couple cases of Nosler varmint 22-250 ammo during a bogo promotion. I shot some this summer, I found that Rem 9 1/2 primers would seat a couple thousandth proud, I had to use a uniformer or CCI primers. I choose to use the uniformer.

 

[K22]

I started uniforming pockets about 5 years ago w/ a Sinclair uniforming tool mainly because it was impossible to remove all the residual primer compound with a standard primer pocket cleaning tool. Uniforming provided a square, shiny, flat bottom making it easy to remove all the primer compound.

I also hoped that a uniformed pocket would improved the precision of my reloads - it didn't as far as I can determine so I'm wondering why I'm still doing it. - probably to justify spending the money on the Sinclair tool.

 

[Sandstorm]

Yea me too...

 

[Scott Harris]

I know that uniform cases in every aspect is the goal. But I have never had a piece of brass that required modifications of the primer pocket in any way. I dont use crimped brass. So because I have never, should I be checking and uniforming pockets for reasons other than functional reasons.

Hmmm, check em, yes. With Lapua brass, I can't remember having to do any work on primer pockets. My .02, this task is way down the list of important things to do...i.e. it's on the un-important task list. I only speak for Lapua brass though.

 

[AJC]

Is this chore mostly avoided by using premium brass like Peterson, lapua, ADG and more necessary with high volume brass like Remington,Winchester, or foreign imports like IMI, CBC, etc. Does anyone have experience that a certain clambering is more problematic than others.

 

[rsmithsr50]

the longer the distance,, the more attention you pay to details.
short range bench rest skips a lot of things that are common at 1000 yard bench rest.
if your particular shooting is not "precision", then there are lots of things you can skip.

 

[Sniper338]

I do it.. its shown a tad improvement on paper for me. I do it to new brass, then a second time after the first fireing just for any clean up. The brass flows a tad bit after the first firing and a bit more is cut out. I use the sinclair hand tool. I cant say ive seen a difference with everything... 6xc, 6.5 grendel and 260 lapua yes... 6br and 338 lapua no. 6br lapua brass is usually hella good from the get go. Never decided on my 308. I do have a primer tool that sets each primer at the same depth, but its all possibly my theory or in my head. I saw the most improvement with lapua grendel brass.

 

[Brians356]

All of the many short range group benchrest competitors that I know seat primers by feel, not to a specific depth. I have never seen any on target evidence that uniforming pockets enhances accuracy, even at the highest level. Even if the pockets are of uniform depth, primers are not. IMO there is a lot of untested assumption going on in this area.

I uniform pockets, but not to produce some specific seating depth. I seat by feel, using the venerable (discontinued) round Lee Auto Prime thumb exerciser. Uniformed pockets (in non-premium brass) gives me a more consistent feel of the primer bottoming out, that's all. It may be imaginary, but as Sammy sang it "I gotta be me!" I don't bother touching up Lapua cases.
-

 

[jimmymac]

I use this right out of the gate on new brass then every firing thereafter for clean up. It’s fast and simple chucked on a cheap 4v cordless driver.

https://kmshooting.com/small-pistol-rifle-primer-pocket-correction-tool.html

Does it improve accuracy? I don’t know, but it hasn’t hurt accuracy so I’ll continue with this easy to use tool.

 

[Coyotefurharvester]

I have a bunch of new Rem nickel 17 rem brass, I grabbed a couple and the Lee Auto prime could just seat flush or slightly proud with 7.5's. Measuring some pockets around at several spots I found some are short of .123(Rem 7.5 primer). I had CCI 450 they were .120-0.1215. BR4 0.120. I will have to get a small primer uniformer, not sure if it is a plating issue or irregular manufacturing(probably a combination). I could seat below flush with the RCBS press primer attachment, but took a firm push.

 

[GSS]

I know that uniform cases in every aspect is the goal. But I have never had a piece of brass that required modifications of the primer pocket in any way. I dont use crimped brass. So because I have never, should I be checking and uniforming pockets for reasons other than functional reasons.

I think we may be missing some relavant info in your question;

Are you loading for and asking about primer pockets on reloads for;
A 30-30 hunting rifle for 100 yards an in Deer hunting ?
or
A 1000 yard benchrest rifle ?
or
Something in between ?

I justread the whole threrad and I'm still unsure of what rifle / application YOU are actually asking about.
George

 

[AJC]

I think we may be missing some relavant info in your question;

Are you loading for and asking about primer pockets on reloads for;
A 30-30 hunting rifle for 100 yards an in Deer hunting ?
or
A 1000 yard benchrest rifle ?
or
Something in between ?

I justread the whole threrad and I'm still unsure of what rifle / application YOU are actually asking about.
George

It was a general question. I am not trying to gain anything but knowledge. I currently do not do anything to primer pockets on any of my reloads from 9mm to 308. If there was a significant improvement I would be interested in my 223 and 6mmbr that I shoot out to 600 yards for steel siloette. This is an area of case preparation I see covered as important but I have yet to see anything published in articles or any testing. I totally understand the practical reasons for fixing pockets to shallow to function properly. Where does pocket uniforming fall on the list of important things to do.