Primer pocket uniforming

[tcoz]

Until very recently I had never reamed or uniformed a primer pocket in any of the rifle calibers that I reload. I used an RCBS wire brush to clean them but that's as far as it went. Priming (on a LCT or Redding T-7) was never my favorite step in the process just because primers didn't always seat easily even though I had developed a pretty good feel for seating them.
Recently though I had a problem with a few FTFs in 30 carbine which I traced back to primers not being fully seated even though they felt OK.
I decided to buy an RCBS primer pocket uniformer and attach it to my FA case prep system in place of the wire cleaner brush. The difference it's made is unbelievable. Every single primer seats easily (but not loosely) and there's no mistaking that each one is fully seated.
If you don't already uniform your primer pockets, consider doing it. If you already clean the pockets, it doesn't add a step, it just replaces the cleaning. Some people say it also removes military crimps but I haven't tried that yet. It would definitely be an added bonus if it does.

 

[mmorris]

I uniform all primer pockets, but it only needs to be done once.

I think it improves the fit of the primer, and I don't agree that it's preferable to bend and crush precision parts when they can be made to fit perfectly.
You can do it... but I don't agree

 

[Rule3]

I don't clean or uniform them. I am no bench rest shooter but have no primer failures on 556 or 308. Bolt or semi auto, I used Wolf, CCI and Win primers.

But if it helps go for it.

 

[macgrumpy]

Bench rest shooters aren't the only people that like to have uniform and clean primer pockets, anybody that wants precise and safe hand loads do it too.

Uniforming the pocket will ensure that the primers seat in the same place relative to the base of the case, if you don't mind that your primer cup heights vary by a few thousandths of an inch then I guess it doesn't matter. Those of us with free floating firing pins are foolish if we don't do it, a primer that is seated a few thousandths of an inch higher could cause an out-of-battery ignition.

Primer pocket uniformers are not made to remove a military crimp on the pockets, sometimes the crimp can be removed but it depends on the hardness of the brass and the finish of the uniformer. Buy the correct tool for the job, they leave a uniformly shaped radius to the pocket that actually helps center the primer when you seat it. Unlike the uniformer, the crimp remover is a one-time activity.

Those that think that the uniformer is removing the crimp don't understand whats really happening. The uniformer is simply acting like a swaging tool, it is pushing the brass out of the way to make room for the tool. This creates a lot of heat and stress on the brass, it can harden it needlessly and leave a rough interior lip on the pocket.

Uniforming isn't necessarily a one-time event, it depends on how hot your loads are and how many times you've used the brass. The bottom and the sides of the pocket move during the ignition process. If you use hot loads I'll guarantee that the pocket dimensions have changed after two or three reloadings.

 

[tcoz]

My comment about the uniformer removing crimps was just informational. I use a military crimp remover and don't plan to change anything. Based on reports I thought I'd check it out of curiosity.

macgrumpy, are you saying that running the uniformer through each time instead of using the cleaner isn't a good idea? I realize the primer pocket doesn't need to be uniformed each time but the tool does a better job of cleaning than the cleaner does. The RCBS uniformer has a hard stop so you can't overdo it.

 

[LiveLife]

I buy military .308/5.56 brass with crimped primer pockets.

After much research, I thought the Dillon Super Swage 600 was what I was looking for but found the $35 C-H Swage Kit to be faster - https://www.ch4d.com/products/equipment/case-tools/psk

Video of C-H in action - https://youtu.be/oFD3jJ9AEXk?t=250

 

[cheygriz]

I've been reloading since 1965, and I've never seen the need to clean or uniform a primer pocket.

Not even on my 1/4 inch group ammo for my heavy barrel 6MM Remington and .22-250

If using a free floating firing pin, such as in the M-1, just use MilSpec primers like the Remington 7 1/2 or 9 1/2, or CCI 34 and 41.

 

[Rule3]

Scroll to post #10 Uncle Nick

https://thefiringline.com/forums/showthread.php?t=462309

 

[macgrumpy]

macgrumpy, are you saying that running the uniformer through each time instead of using the cleaner isn't a good idea?

Nope, I was just pointing out that the primer pockets always change dimensions, personally I always use a uniformer when I prep my brass.

As for those that justify not uniforming their pockets by saying that they've never had a problem, I hear that answer all the time, even from guys that complain about the poor design of the M1 Garand causing slamfires. It sort of reminds me of one of those "hold my beer and watch this..." jokes. People get away with doing a lot of stupid things but every once in a while it'll bite 'em.

As for primers being MilSpec, no commercial primer is a MilSpec item unless the military inspected it and approved it for their ammunition and any primer lot that has been inspected for military use isn't available to public, it's used by the military. If you're going to conclude that those primers are MilSpec then you have to include the Federal 205MAR because it was also used by the military. Regardless, there are a lot of people that believe that using these 'MilSpec' primers is the answer when all they have to do is make sure that the primer is seated to SAAMI specs and they won't have to worry about primer problems...and a uniformer tool will ensure that they seat to SAAMI specs.

 

[tcoz]

I have to confess that I was one of those people until I was able to determine that a few FTFs I had weren't due to a problem with my carbine or my use of CCI41 NATO primers. Uniforming the primer pockets not only cured the problem but also made primer seating easier and much more consistent.

 

[Rule3]

Off the topic but was brought up.. Kinda like cleaning primer pockets,

How many manuals or online powder data call for a Military primer say a #41?

What did people use before the folks marketing those primers "convinced" us that we needed them?

My Speer. Hornady. Layman all use regular SRP or LRP
None of those manuals make any mention of pocket uniforming? If the brass fired properly the first time the pocket must have been OK? If reloading MAX loads distorts the pocket then maybe that is a concern, or perhaps it is problematic with the M1, I do not know as I don not shoot one.

Shall we uniform pistol brass also? My SW 460 Mag has more PSI than a 30-06.

 

[Nature Boy]

THR member "Slamfire" would be the one to answer that question.

 

[spitballer]

I uniform all primer pockets, but it only needs to be done once...

Excellent image mmorris, illustrates reason for time needed to clean primer pockets: the pocket is not flat on the bottom and doesn't lend itself to a flat scraper-type pocket cleaner! However, it occurred to me that the existing pockets with the bowl-shaped center area might actually channel the primer blast a little better.. have you noticed any difference in performance after this modification?

 

[tcoz]

How many manuals or online powder data call for a Military primer say a #41?

What did people use before the folks marketing those primers "convinced" us that we needed them?

I was using CCI 41 primers because I had an over abundance of them and wanted to use some before changing over to the standard SRP.
This isn't the place for another discussion on the merits of using NATO primers but I just want to say that I've never seen any advertising or marketing materials that are trying to "convince" me that I need them. I use them in my ARs and my M1 Garand because they can offer an extra level of protection and because my LGS sells them for the same price as standard primers.

 

[cheygriz]

According to the NRA dope bag the Remington 7 1/2 primers and 9 1/2 are the exact primers used in Remington military ammo.

CCI states in the literature that their 41 and .34 primers MEET MILITARY SPECIFICATIONS, IOW, they're MilSpec.

I'll believe the NRA and CCI before some "internet expert."