Pls explain "staking"

[questor]

Few questions on "staking":

1. What is “staking” and how do you recognize?

2. How is “staking” different than crimping?

3. Why “staking” any benefit or something just done in 3rd world countries?

4. Any difference on the primer discharge into the powder?

[jack404]

Staking is the direct impressioning or denting the cartridge surround instead of a formal crimp between the cartridge case and the projectile , normally found in some former soviet nations ammo , primarily for primers its also found in mujaheddin home made ammo and not a great solution

[Alpo]

These primers are crimped.


These are staked

[Alpo]

Hard to make out in that second pic, but that's Lapua. Not what one normally considered "3rd World Country" ammo. Greek ought-six is staked. I believe US 50 BMG is staked.

[jack404]

Alpo i meant for retaining the projectile primer staking is common in mil and other hi power ammo but for the projectile ??

[questor]

If Lapua and 50 BMG are staked, is there an advantage over crimp primers?

[jack404]

takes more pressure

but makes reloading a hassle

gotta trim the stake marks and align the case so the next lot not overlap the existing ones to ensure a correct seal so this greatly limits the time of safe reloads

you may get 1-2 or 3 reloads only unless you take real care with each one

[questor]

This all started when I ended up with a can full of Egyptian 9mm ammo. My G17 and Ruger P85 was unable to fire them (note: 1st image). My friends Kimber CDP II didn't have any issues with them. That is when I learned a new word "staked"

[Alpo]

I think staking is probably cheaper, and also probably easier. That's why it's used. The purpose of the crimped primer is to keep it in place during full auto fire. If three stake marks will do that as well as a full crimp, for the one time that it's going to be fired, and you can stake it for .001 cent, while a full crimp costs .0015 cent, over millions of rounds that is a substantial savings.

I swage my primer pockets. That pushes both full crimps and stake marks back into the pocket wall. I think that's better than trimming. Some don't agree.

Reloading problems should not matter with that 9, since I'm fairly certain it will turn out to be Berdan, and not reloadable (at least, not easily).

The only reason I can come up with a firing problem with that stuff is it might be sub-gum ammo, and has a harder primer, and your Glock and your Ruger just don't have enough umph in the mainspring to pop 'em.

1911, though --

[LDBennett]

questor:

Primers are staked or crimped into their pockets to avoid rough handling that might make them fall out. It is a military ammo practice. That ammo, after all, is subjected to much rougher handling than any of us would normally give ammo.

Surplus ammo, as you have there, is a crap shoot especially if made in a foreign country. Some is good and other not so good at all.The other countries tend to make the ammo for the guns in their arsenal which are sometimes military special guns with specs sometime different than commercial versions.

Your failures to fire could be bad primers or just that your commercial gun does not have the firing pin mass and velocity or the "correctly" shaped firing pin to set off the ammo's extra thick primer cup primers. Since it appears to be 9mm for use in a semi-auto and is taper crimped, it could be the cases are a bit too short and the firing pin reach not far enough or the taper crimp over done allowing the cartridges to seat too deeply in the chamber. Middle East ammo manufactures do not have a very good reputation, I'm afraid. But the Greek 30-06 ammo CMP sells is very good stuff and the used brass is excellent for reloading (I know, I have used it!).

Another gun might not have any problems with using your ammo but that is not the case if the ammo's primers have a problem.

One reason that I refuse to shoot any surplus ammo is that most has corrosive primers. Old primers were corrosive in nature but lasted much longer before deteriorating than modern non-corrosive primers. Even the USA used corrosive primers until the early 1950's. Foreign ammo is more likely to still use corrosive primers. Guns used with corrosive primers must be cleaned immediately with soapy water then flushed with clear hot water or corrosion will start inside the barrel and internally to the gun. Most regular gun solvents will not stop the corrosion. The salts created by the corrosive primers are water soluable and are anhydrous (draw in moisture from the air to make an acid that attacks the steel). Only water dissolves them and remove them from the barrel and internals during cleaning. The gun should then be re-cleaned with regular gun solvents and re-oiled as the soap removes all the oils on the metal surfaces. This is way too much trouble for me.

LDBennett

[RandyP]

Some milsurp ammo also has 'staking' done to the case/projectile - there are three of these indents on this 7.62x25 stuff.

[aa1911]

I used to trim all my primer pockets until I discovered Dillon's swaging tool; I much prefer to swage now for 1) easier (on the fingers anyway) 2) brass conservation.

I've got a bunch of Israeli mixed headstamp 7.62 NATO, most of it is staked. Surplus ammo is OK in some cases but can be worthless in others. (pun intended)

[LDBennett]

aa1911:

I too have used the Dillon swage tool for primer pocket reforming but there can be a problem with using it.

It relies on brass having uniform thickness of the web of the case. That is, the area between the outside rim area and the inside volume of the case. The mandrel pushes from the inside as the tool head swages the primer pockets to size. if the thickness is different then the tool does not work well. It is spelled out clearly in the instruction sheet that comes with the swage.

You would think that Lake City brass would be uniform at least for the same year headstamp but you would be wrong. There are difference between years too. I found I could not use it on the 1000 cases of various year Lake City brass I got in 308. I had to resort to other means that removed metal. Primer pocket truing and primer pocket reamers did not work all the great either. None would remove all of the rolled over edge of the pocket so that the pocket was a uniform diameter top to bottom. A common counter sinking tools worked the best but did remove more metal than I would have liked.

The Dillon primer pocket swage is a nice tool but does not work on all brass. That is at least my experience. Your experience may differ. My experience matches what the Dillon instructions say can happen, unfortunately.

LDBennett