Is uniforming primer pockets for functional or accuracy.

[AJC]

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.

 

[Mad_Charlie]

I shoot a lot of semi auto, I do it mainly for safety reasons after a few firings, don't want any high primers. Some folks claim enhanced accuracy, but I don't shoot good enough to tell.

 

[Straightshooter1]

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.

Guess it would depend on what level of shooting you do.

I know that the amount of crush a primer gets effects the flame going through the flash hole. Getting a consistent ignition of the powder from the flash hole tends to affect the interior case pressure's consistency. If one doesn't have uniform primer pockets, there can be issues with inconsistent seating/crush of the primer. Some shooters, especially some competitive shooters, will go to extremes to get uniform pockets AND primer seating as part of getting a well tuned cartridge.

 

[XLR308]

For the most part I only use Lapua brass when it is available in the calibers I shoot and all I have ever done is just debur the inside with a K&M tool and done.
I have spot checked primer pockets on them with a uniforming tool but have never found an issue with them that required any attention and no I don't shoot benchrest matches.

 

[AJC]

It depends on do you want to win or just shoot ?

I'm curious as to which discipline you refer to

 

[1shot]

Guess it would depend on what level of shooting you do.

I know that the amount of crush a primer gets effects the flame going through the flash hole. Getting a consistent ignition of the powder from the flash hole tends to affect the interior case pressure's consistency. If one doesn't have uniform primer pockets, there can be issues with inconsistent seating/crush of the primer. Some shooters, especially some competitive shooters, will go to extremes to get uniform pockets AND primer seating as part of getting a well tuned cartridge.

I am firmly in this camp.
I would recommend NOT squaring the primer pockets until after the first firing. There will be a dimensional change when fired (no matter how slight) on new brass.
I hope this helps,

Lloyd

 

[ebb]

yes

 

[JimSC]

both

 

[JMayo]

I don't grind on primer pockets and do well in br.
I have 30 firings on some 6mm.

 

[rsmithsr50]

the problem with asking a general question instead of a specific question.
the further the distance, the more attention to the details.

I don't grind on primer pockets and do well in br.
I have 30 firings on some 66mm.

 

[Bill K]

It can help in both ways. Just part of working up a good accurate load for a given rifle/handgun.

 

[6MMsteve]

I quit primer pockets 6 yrs ago, I uniform the flashole and that's it,,I moved to other details that has improved my shooting a bunch...mainly from reading and listening on this great site..finding a routine and sticking with it has made my groups smaller and more consistent..mainly good barrels and bullets..brass primers & case dimensions..plus shooting a lot

 

[BoydAllen]

Guess it would depend on what level of shooting you do.

I know that the amount of crush a primer gets effects the flame going through the flash hole. Getting a consistent ignition of the powder from the flash hole tends to affect the interior case pressure's consistency. If one doesn't have uniform primer pockets, there can be issues with inconsistent seating/crush of the primer. Some shooters, especially some competitive shooters, will go to extremes to get uniform pockets AND primer seating as part of getting a well tuned cartridge.

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.

 

[rsmithsr50]

the entire world does not revolve around short range br.
(the problem with asking a general question instead of a specific question.
the further the distance, the more attention to the details.)

 

[BoydAllen]

the entire world does not revolve around short range br.
(the problem with asking a general question instead of a specific question.
the further the distance, the more attention to the details.)

I never said that it did. I still maintain that for most shooters it is a waste of time. Certainly, I agree that long range has different requirements, but the latest developments in that sport, glue-ins and doing some loading or load adjustment at the range, have come from short range haven't they? Have you seen any research on whether uniforming the best brass makes a difference for long range?

 

[AJC]

I never said that it did. I still maintain that for most shooters it is a waste of time. Certainly, I agree that long range has different requirements, but the latest developments in that sport, glue-ins and doing some loading or load adjustment at the range, have come from short range haven't they? Have you seen any research on whether uniforming the best brass makes a difference for long range?

I was hoping that one of the top shooters here had some test data, because they seem to test everything. If your weighing primers and sorting them, you just may have some primer pocket data.....

 

[Ralph Littlefield]

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.

 

[mikecr]

Well, I happen to set specific crush with primer seating.
Fed/Win/Rem at 2thou crush, CCI at 5thou, as standard.
I didn't go there because I wanted to, but because it makes a difference with hunting capacity cartridges.

My seating to crush accounts for varying primer heights (via indicated K&M).
I set pocket depths with Sinclair pocket tools, in hopes that striking distance would then vary only by primer height(minus crush) to pocket bottom.
Good to less good striking is a window way bigger than this, but it doesn't hurt provided I'm not taking much material from pockets.
I watch all fired primer appearances, and I want them all the same, barring 1st indication of problem.

What I do not do is mess with flash holes. Guess that makes me an outlier, but my testing showed either no improvements or worse performance in doing so.
I only inspect them, and toss off-center holed and pronounced burrs.
And I hold an eye tolerance for this much.

 

[Straightshooter1]

Well, I happen to set specific crush with primer seating.
Fed/Win/Rem at 2thou crush, CCI at 5thou, as standard.
I didn't go there because I wanted to, but because it makes a difference with hunting capacity cartridges.

My seating to crush accounts for varying primer heights (via indicated K&M).
I set pocket depths with Sinclair pocket tools, in hopes that striking distance would then vary only by primer height(minus crush) to pocket bottom.
Good to less good striking is a window way bigger than this, but it doesn't hurt provided I'm not taking much material from pockets.
I watch all fired primer appearances, and I want them all the same, barring 1st indication of problem.

What I do not do is mess with flash holes. Guess that makes me an outlier, but my testing showed either no improvements or worse performance in doing so.
I only inspect them, and toss off-center holed and pronounced burrs.
And I hold an eye tolerance for this much.

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?

 

[danny]

I slammed off about 5-6 or so rounds in my AR many years ago. I was using a primer pocket uniformer from Sinclair International that proved to be defective (too short). In my experience in those days, I was seating the primers in below flush, though they were crushed in, in too short of a primer pocket. I use a primer pocket uniformer for safety only and don't give one thought to any accuracy gain. After uniforming A LOT of brass since then, I have almost never seen a Primer Pocket Uniformer not removing brass, re-establishing the depth set by the uniformer (which is set ny manufacture and can't be changed).

Danny