Musings on Primer Pockets – How Obsessive Can We Get Really?

Match Grade M1 Garand in 30-06.

Match Grade M1 Garand in 30-06.

Primer Pockets

There are two types of primers and pockets, one of which is considered to be reloadable and the other not so much, Boxer and Berdan. Boxer Primers are the ones used on US commercial and military centerfire ammunition. Boxer Primed cases feature a single flash hole in the center of the primer pocket and an anvil (the part against which the blow from the firing pin crushes the priming material igniting the priming material and thence the main charge) which is pressed into the primer cup itself and removed and replaced as part of each new primer. The Berdan primer is used in a two flash hole primer pocket with a small nipple located between the holes (part of the case itself) which serves as the anvil. The entire thing for our part simply boils down to the fact that it is much easier to “de-cap” the case by plunging a depriming pin through the single centrally located hole of the Boxer primer arrangement.  Our conversation from this point forward applies strictly to Boxer Primed Cases.

Well, in a different segment of this blog, I promised you that I would talk about crimped primer pockets on military brass, but while I was thinking about it, I kind of decided I’d roll all the primer pocket issues into one seriously boring post.  I really hate primer pockets, but we have to deal with it, so here it is!

First – Dealing with Military Brass:

As I mentioned earlier, most US military brass has crimped primer pockets.  Since military ammunition is designed to be manufactured, and then stored until needed, shot and left behind advancing troops, the cases are treated as disposable.  The bullets are frequently seated into the case with a sealant, and the primers are crimped into place with a pressure ring pressed into the primer pocket, to seal and retain the primer.  In order to reload these cases once fired, we need to remove this crimp before inserting a new primer. Thankfully we only have to perform this task once.  The other things we need to deal with, especially with military brass are, case length, and chamfering/deburring the case mouth.

Crimped Primer Pockets:

There are two basic methods of dealing with pocket crimps, reaming and swaging.  Reaming involves removing material by cutting it away, and swaging uses force to stretch the brass and flow the crimp material back into the case head.  Reaming can be done sitting in front of the TV with a towel or rag on your lap to catch the shavings. Swaging on the other hand needs to be done at your reloading bench, unless of course your significant other doesn’t mind a reloading press mounted into the coffee table. Again the reason for performing either of these operations is the insertion of a new primer which is rendered difficult if not impossible in the presence of said crimp

Reaming:

Reaming is done with a primer pocket reamer, a simple handheld device. Simply insert the end that fits into the pocket and then twist the little bugger until you feel it move freely.

Sorry about this image, It's the only one I found quickly..  Stick the small end in the primer pocket and twist 'til it moves freely.

Sorry about this image, It’s the only one I found quickly.. Stick the small end in the primer pocket and twist ’til it moves freely.

The downside of the PPR is quite simply the potential for inconsistent results, out of round pockets, overly reamed pockets etc.  The other downside is sore thumb and fingers, and a slow process relative to…

Swaging:

Hie yerself back to the fortress of solitude (or wherever your reloading bench is located) after you pick up a Primer Pocket Swaging Combo, available from RCBS and others, and get thyself ready for some noisy fun. This may be the most raucous operation in the reloading process.  The tool (set) consists of a die, 2 swaging nipples, 2 die case rods, and a steel cup that fits over the nipples and performs the removal of the case from the nipple. This seems to me the noisiest part.

RCBS Primer Pocket Swager Combo

RCBS Primer Pocket Swager Combo – The Case rods are not shown.

OK so here’s the dealio, basically you choose either the large or small components depending upon what size primer pockets you are dealing with.  In the case of these ’06 cases we’re going large.  Screw the rod into the die.  The die by the way is totally non specific, it really just holds the rod in place.Case Head SeparationThen take the appropriate nipple (in reality the Primer Pocket Swager) and insert it into the case holder socket on your reloading press ram. Then drop the removal cup over the nipple.

Insert the swaging nipple into the shell holder slot, and drop the removal cup over the nipple.

Insert the swaging nipple into the shell holder slot, and drop the removal cup over the nipple.

Slipping Case over nipple

Slip the empty case primer pocket over the swager nipple and guide the case into the die over the rod.

Next you take the case, whose primer pocket you wish to swage and slip it over the nipple. Straighten the case and slowly raise it into the die around the rod. Next, raise the ram fully forcing the swagger nipple fully into the primer pocket.  Lower the ram and at the bottom end of its travel vigorously “Pop” the case off the nipple. What happens is the cup hits the lower arch of the press while the ram continues down and thus pops the case off of the now firmly stuck nipple.  The result is a nicely de-crimped primer pocket.  The side effect is a great deal of crunching and clanking noise as the ram forces itself past the crimp and clunking and clanging as the case pops off the swager nipple and the cup rings like a bell,  Like I said it’s noisy!

While hard to discern the difference in this image, the case on the left has been swaged, the one on the right still sports the crimp. The most obvious sign of this is the presence of more red primer sealant.

While hard to discern the difference in this image, the case on the left has been swaged, the one on the right still sports the crimp. The most obvious sign of this is the presence of more red primer sealant.

Next up is Primer Pocket Cleaning – Myth or Mystical? Stay Tuned!

Primer Pocket Cleaning: 

As you can see in the image directly above, the primer pocket is kind of grungy.  There’s black gritty soot deposited in the pocket. This can be removed with a steel brush made for the purpose called, would you believe, a pocket cleaner by RCBS, of course everybody makes them.

Image of Primer related hardware

Some assorted Primer Pocket related hardware including reamer and pocket cleaning brush

If you are not aware of a thing called RSI, this is a perfect way to find out what it is. You take the brush, shove it into the hole and “Turn, Turn, Turn.” The pocket comes out kind of clean. By the time you are finished with say a hundred cases, your wrists will be screaming, your fingers will be sore, and you’ll wonder whether or not this is actually worth it, Frankly, the jury is still out. Some folks clean their primer pockets, some don’t.  I don’t unless I am making up match ammo, or working up loads with a chronograph. Some guys do it religiously. You decide.

Next Up, “Priming Cases The First Step in Making Great Ammo”

Or for the truly obsessive compulsive, “Case Prep The Easy Way and The Hard Way”

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About Gary L. Miller

I have many hobbies and spend a fair amount of time playing at them. I'd love to spend more, but there's this earning a living thing... So I often fill my idle hours spewing forth ideas and opinions, unsolicited or not. This is merely an extension of that propensity.
This entry was posted in Reloading for the Rifle!, The Arts of the Fusilier and tagged , , , , , , . Bookmark the permalink.

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