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canuck
06-16-2015, 11:09 PM
Is it ok to use a Sinclair primer pocket uniformer to clean out the carbon from the primer pocket after each firing?

mike in co
06-17-2015, 01:27 AM
yes and you may find that the depth of the pocket changes as you fire the brass...

canuck
06-17-2015, 08:01 AM
thanks for the input....I just wasn't sure......

4 Liberty
06-27-2015, 08:45 PM
Is it ok to use a Sinclair primer pocket uniformer to clean out the carbon from the primer pocket after each firing?
You can use anything that fits without taking any brass off.

mike in co
06-28-2015, 10:07 AM
why would he not want uniform primer pocket depth ?


You can use anything that fits without taking any brass off.

Boyd Allen
06-28-2015, 10:16 AM
It is not that it is not desirable, but that given that primers vary in thickness, even if we uniform pocket depth, properly seated primers will vary in depth. Also, how many shooters have actually proven definitively that their accuracy has been improved by uniforming pocket depth? I think that in most cases it is simply a matter of doing everything that is possible to cases in the hopes that accuracy will be improved. Another example would be turning case necks for use in factory chambers. Years ago I tested this, and found no improvement in accuracy. On the other hand, a light cut does no apparent harm, other than increasing an already generous clearance. There are things that do help accuracy, and there are things that are commonly done that IMO do not.

bill123
06-28-2015, 10:48 AM
It is not that it is not desirable, but that given that primers vary in thickness, even if we uniform pocket depth, properly seated primers will vary in depth. Also, how many shooters have actually proven definitively that their accuracy has been improved by uniforming pocket depth? I think that in most cases it is simply a matter of doing everything that is possible to cases in the hopes that accuracy will be improved. Another example would be turning case necks for use in factory chambers. Years ago I tested this, and found no improvement in accuracy. On the other hand, a light cut does no apparent harm, other than increasing an already generous clearance. There are things that do help accuracy, and there are things that are commonly done that IMO do not.

Would flashhole chamfering fall into the don't bother category?

Boyd Allen
06-28-2015, 11:45 AM
Depends. There was a test of Lapua brass (6BR if memory serves) that indicated that anything done to the flash holes degraded accuracy slightly, but those are drilled holes. For punched holes, that may have various issues at their inside edges, I would definitely chamfer, and make every attempt to do it minimally and uniformly.

Wilbur
06-28-2015, 12:13 PM
Folks surely do a lot of things that neither help nor hurt.

zippy06
06-28-2015, 01:50 PM
Would flashhole chamfering fall into the don't bother category?

With Lapua brass, I found accuracy improved when I stopped flash hole reaming, cutting, or messing with it. The hole is .059" for a reason....

mike in co
06-28-2015, 01:59 PM
the problem i see with some reloaders is failure to seat the primer to the bottom of the primer pocket.
a uniform pocket depth makes it much easier to seat to the bottom of the pocket.
add a small crush and you are done.
if you do not seat to the bottom of the pocket, the firing pin must move the primer to the bottom of the pocket and then ignite the primer...
since it used energy moving the primer to the bottom of the pocket, you have a less uniform ignition.

none of this is new , it has been discussed multiple times.

primer pockets can change depth in use.
if consistency is your goal , then do things that promote consistency.
i seldom see double digit es's

bill123
06-28-2015, 03:15 PM
Boyd & Zippy06-Thanks for the information. Saved me a step next time around!

Wayne Shaw
06-28-2015, 06:02 PM
I use the tool to SQUARE the pocket. The edges have a radius, and I think the pocket should have a square bottom. Usually by the time the tool starts to hit where the flash hole is, I quit. Primers seem to seat better for me.

canuck
07-13-2015, 08:52 AM
Some more invaluable tips..I know you guys probably get tired of what seems like simple questions but this is the only site I trust to get the right answers.....I can't believe how much I have learned on this site in the last few years.....Thank you again gentlemen.....

Lee Martin
07-13-2015, 09:50 AM
With Lapua brass I never prep the pocket. Instead I use an RCBS primer pocket cleaner to knock out the carbon:

http://www.brownells.com/userdocs/products/p_100010244_1.jpg

Never had a need to touch the flash hole.

-Lee
www.singleactions.com

Dave B
07-13-2015, 03:47 PM
Alvin told me" I do 10 different things with my brass prep. Only 7 of these things are important, I just don't know which 7."

Mozella
07-14-2015, 03:17 AM
With Lapua brass, I found accuracy improved when I stopped flash hole reaming, cutting, or messing with it. The hole is .059" for a reason....

Well, Lapua brass is expensive for a reason. Actually, compared to most other brass, it's quite expensive. However, it's also the most long lasting and is literally ready to load.

Not so with something like Lake City. Take a look inside the cases sometime. Lapua has a nice flash hole which appears as if it's drilled. Lake City looks like it was shot with a small caliber rifle and there are often large ugly burrs on the inside.

I haven't tested flash hole de-burring alone as it relates to precision groups but I have spent some time fine tuning my cheap brass to include careful trimming, chamfering, flash hole de burring, primer pocket uniforming, annealing, and sizing in attempt to make a silk purse out of a sows ear. There is definitely an improvement in performance with carefully prepared brass but I can't say what percentage (if any) is attributable to improving the flash hole.

I would say it makes sense that a flash hole without a bit ugly burr would better and since it's only an additional two or three seconds time on my case prep machine, I do it with cheap brass. I already have the case in-hand from chamfering so sticking it on the deburring tool for a second or so is no big deal and I only have to do it once.

But, since Lapua is so well made, it's not necessary to dress it up to this extent. And, as you pointed out, messing around with a perfect flash hole is not likely to improve things.

Bottom line: If your flash hole has a big burr, get rid of it. If not, leave it alone. Now you have my two cents. :cool:

Doug Casner
07-14-2015, 10:08 AM
Lake City brass the primer pocket and headstamp was punched into the head by a big horizontal press. Operation called heading. Ran a bunch of them. That was 20 years ago. I don't know what they do now. Doug

Fretka
07-14-2015, 12:56 PM
I recently prepped a blue box of Lapua .220 and noticed that the cutter for the flash hole would not spin smoothly indicating some small amount of "punch of drill flash" left over from manufacture. IME it is a step worth doing but YMMV.