Champfering primer pockets

OK, educate the ignorant, Sorry for being slow. I swage large and small primer pockets and have never had a problem. I am always hesitant in removing material. What am I missing. Thanks!

Blue68f100 said:

But removing brass weakens the base to some degree, all depends on how hard your pushing the pressure.

Click to expand...

I was all with you until you got here as putting a bigger chamfer on the primer pocket can lead to some issues with high pressure loads, but weaken it? No, I don't think so unless an old balloon head case. That little bit of lost brass isn't going to weaken the case head of modern brass.

I use and love the Hornady tool.

One thing I do enjoy about commercial 223Rem brass, as compared to military-esque 5.56, is the generous chamfers afforded to it. Especially the Remington Peters, nice wide curved chamfer.
Easy hand priming, with no binding or snapping that may jostle a primer upside down or sideways.

In my experience, the RCBS pocket swage is not ideal. It may swage the path clear, but there is no realistic way to get it far enough into a pocket to chamfer the stake crimps over.
Believe me, I’ve tried. A lot. It will be stuck when you hit the curve. And the press will have to be pounded to get it back off the pin.
That kills my Zen.

I, too, grabbed a counter sink and cut the remaining edge catchers off in order to have smoother, trouble free priming.
Then an epiphany! Why not just buy commercial brass and not mess a whit with it?
Well, because it’s just setting there being wasted! Just lying in the dirt, discarded, maybe even lonely! That’s why!

So with all the extra I do to my finer target brass, Lapua gets my money, saves time in all sorts of ways.

Then I chamfer the rest and run it through an AR again!

(On weakening the case head.)

I was thinking, one could take a case and sand the head down perpendicularly further and further until the primer protrudes from the pocket and the case begins to slam fire and becomes dangerous. If one is careful to keep the primer in place and continues a rupture could occur, with intent.

A 45° countersink will remove material until the primer begins to rupture and etch the bolt face, which makes it easier to pop the primer out on the unsupported area.
To make the head weak enough to split would be to make it unable to hold a primer at all.

Both of these situations are huge problems that I would never allow in my firearms! Just thinking aloud.

But I figure that Sig and R-P put them on their cases for a reason, whether to our benefit or theirs.
https://www.rcbs.com/case-processing/primer-pocket/trim-mate-military-crimp-remover-2/16-90387.html
This will put a perfect one on.

If your cases are trimmed properly consistently, they can be put in the trimmer backwards with a chamfer tool head on the trimmer. Then, every case will have the same four thousandths deep chamfer.
I also do this for VLD chamfering and de-burring the mouth after trimming for identical as I can make it bullet grip.

I did a bunch with a common chamfer tool for case mouths a little while ago and it is less than ideal. Sometimes, a couple really easy turns and the checker will go in and out of the pocket, but - I think it turns a bit of an edge of the brass and creates a bit of a lip, so - then your into really taking out a good bit of metal, just like the actual little hand tools designed for the pockets, but - you have to do it like 10 times as long - or I just never figured out the technique to it with the chamfer tool, but - for 8$ or whatever, makes sense to have one of the tool designed for the job.

Glad the Pocket Swage II worked well for you.
Interesting that the same company makes both tools...

Have a good day today, it’s spring, and we’re all above ground!

AJC1 said:

S and b brass is just as terrible in 357 as it is in 38. I smashed 3 out of 100 primers the last time I tried to prime some. Planning on using a drill bit to very lightly by hand chamfer the primer hole. Is there a more obvious choice or better way. I could use a countersink.

Click to expand...

I run into that problem with around 40% of my S&B 10mm. I picked up Hornady's primer pocket reamer a while back. It works well, but reaming by hand gets old after a while. I particularly like the way it bevels the outside of the primer pocket which makes primers start much easier. I have yet to use the drill adapter I got for it however. You'd just want to carefully and quickly zap it with a drill. Your primer pockets will be far too loose if you run this tool clear to the bottom.

https://www.midwayusa.com/product/1012762394?pid=804809

I use a Lyman hand held tool that works just fine on my 9mm, 9mm short and 7.65mm calibers. Geez, am I reaming, swaging or chamfering. I dunno. I'm an old man. I just twist it in the pocket a few times and like magic, all the S&B, CBc and other stubborn brass succumbs to inserting my super soft Federal SP primers. Voila!

There seems to be some mis-understanding regarding military cases and the primers in them. Military cartridges generally (with some exceptions) all have the primer crimped in place, or sometimes staked by several punch marks around the primer. The punched stakes are usually found in foreign ammunition. The crimping of the primer is done directly after priming the case and before adding powder and bullet. A machine crimps the primer into place by swaging a small ring around the primer thus displacing (swaging) a small ring of brass around the primer's top which locks the primer in place and it cannot be shaken out by rough handling. What this does in regards to re-loading is that once the primer is removed this leaves a sharp edge around the primer pocket, as well as a small sharp ring of brass that must be either removed or otherwise dealt with.

The two more popular methods are to swage the primer pocket with an appropriate tool (sold by RCBS and other die manufacturers) that re-swages the primer pocket to a standard diameter (SAMMI standard of .1745/.1765 for small rifle and pistol primers) and also puts a small radius on the lip of the primer pocket. A bit of lubrication can be used on the anvil of the swager every few cartridges to ease the operation, however I've never had the need to do so after 40 plus years of re-loading and swaging the primer pockets of thousands of different military cases from 9x19 up to 30.06 cases. Swaging the pockets has nothing to do with pocket depth, all it does is remove the crimped part of the pockets edge and move the brass displaced during the primer crimping operation back where it was before crimping. It is easy to do, very consistent, and enables primers to be seated easily. It's also much faster than the following method if done by hand and more consistent in my experience. The second method is to cut that sharp edge off with a counter-sink (not much different than using a de-burring tool from the manufacturers), a drill bit (carefully used but not as good as a countersink), or even a pocket knife. This removes a small amount of brass rather than moving (swaging) it back, and it leaves a beveled corner (chamfer) rather than a radiused corner at the lip of the primer pocket. And actually a radiused edge is better than a beveled edge as it leaves no sharp edge of any kind, but that is up to the mind of the person. All this entire process does is allow a primer to easily start in the pocket while being pressed into place. The depth of the pocket is a different issue and is handled with other tools which are essentially small reamers that cut on the bottom, similar to an end mill but without cutting flutes. Those tools are usually made with a positive stopping edge so the pocket cannot be cut deeper than SAMMI standards, which is .117/.123 in depth. I would mention that all commercial brass cases have a radius around the lip of the primer pocket, not specifically a chamfer. Sometimes that radius isn't big enough, and that causes problems when initially reloading those cases.

Demi-human said:

In my experience, the RCBS pocket swage is not ideal. It may swage the path clear, but there is no realistic way to get it far enough into a pocket to chamfer the stake crimps over.
Believe me, I’ve tried. A lot. It will be stuck when you hit the curve. And the press will have to be pounded to get it back off the pin.
That kills my Zen.

Click to expand...

All you have to do is put a little Imperial on the pin every so often and everything runs real smooth.

rocirish said:

a little Imperial

Click to expand...

... and Unique, OneShot, P’Blaster, MobileOne and Penetro90(which is a fantastic, moly impregnated, spray lube that I highly recommended for most everything else).

Some brass is tight, Perfecta before tertiary acquisition, GFL and S&B.

And the pin only needs to enter the pocket a tenth of an inch to remove the primer crimp, never reaching the bottom of the pin, where the radius begins to put a slight chamfer leading into the pocket.
Just for fun, run a new piece of brass down till there is no gap between it and the pin deck. Does it make a radius? Is it easy to remove when inserted that far?

But a chamfer tool just makes a chamfer to make it easier to find a hole with a primer. It requires no lube, nor press even.

But I, too, feel as though we’re are all talking past each other, as it is not about making a pin tool work.
It is about whether some of us chamfer an edge to a hole, or not.
In fact, I’ve never even seen a military primer crimp on the OP’s chosen cartridge, 357 Magnum.


I’m just glad we have so many tools to do so many different things, and they all work to the same end, safe and fun ammunition.
I simply, personally, prefer to have my primer pocket’s edges chamfered, or radius-ed with the the RCBS cutter I haven’t even gotten to use yet.

I too have noticed the s&b 357 cases need help. I use my cheap lee chamfer tool. It works, and because it is so small you cannot get a lot of leverage so it cuts slow. That's both good and bad. I've used it to remove the pocket crimp from several hundred blackout over the years, and I always wish I had a better tool after about 5 cases.

Demi-human said:

In fact, I’ve never even seen a military primer crimp on the OP’s chosen cartridge, 357 Magnum.

Click to expand...

You won't find a crimp on .38 Special either as neither .38 or .357 were ever used in anything other than revolvers. They would be the "with some exceptions" mentioned earlier. There is no chance those cartridges would find themselves in combat being used in automatic and belt fed weapons.

I've used many primer pocket reamers and like the RCBS Primer Pocket Swagger best... hdbiker

I use a Dillon 600 decrimper to chamfer tight pockets, it’s very fast. Case specific rods are nice (faster) but not necessary. If you set a cardboard box behind the unit it’s easy to just flick the case off into the box and place a new one on in one motion. Guessing 1 or 2 thousand an hour depending on how if the rod fits the case. Just run the plug into the pocket a little deeper and it does double duty as a chamfer tool. No battling getting the case off the plug like some swage tools.