Will - Steel Case vs Brass Case - Test

[orly152]

Awsome thread...thanks WILL for taking the time to repost this and making that experiment.

[WILL]

Jun 4, 2012 12:03:35 GMT -7 USCGME2 said:

thanks for the info Will, good effort my man. I personally shy away from the steel ammo just cause I like to reload and thats obivously out of the question anyway with that stuff. If one were to store some up for a rainy day, would it be practical to coat the steel lightly with some oil and vaccum pack ? that should let it keep even in humid environs until needed. Just thinking out loud here....

Thanks. I'd be concerned that the steel ammo would cause problems in a situation where you and your gear are consistantly outdoors in the rain, especially in an extended situation. Think check point, OP, roving patrols, day after day, weeks, months on end. For about 4 months a year, you can plan on getting daily rain here in Florida.

[USCGME2]

Good points WILL, I'll just keep buying brass. Good work, worthy of a Mythbusters episode I's say.

[Cwi555]

For the record Will, copper washed steel cases don't work either.
Still going to wait seven days, but they are already enough to cause feeding issues.

[WILL]

Jun 5, 2012 15:15:22 GMT -7 Cwi555 said:

For the record Will, copper washed steel cases don't work either.
Still going to wait seven days, but they are already enough to cause feeding issues.

Wow, they've only been out there for like 3 days, right?

[heysmithy]

This was a really interesting test, I'm glad WC talked you into reposting it because I don't think I saw this before.

[Cwi555]

Jun 5, 2012 15:24:54 GMT -7 WILL said:

Jun 5, 2012 15:15:22 GMT -7 Cwi555 said:

For the record Will, copper washed steel cases don't work either.
Still going to wait seven days, but they are already enough to cause feeding issues.

Wow, they've only been out there for like 3 days, right?

That's correct. The body of the casing is standing up well, but where the neck meets the bullet is going fast. The bottom of the bowl has copper particles in it. That tells me there is a galvanic issue between the bullet and casing. One of theme has .003 swelling at the case mouth, so it has to be galvanic welding the bullet to the casing.
I am going to cross section one at 7 days but given the early results I don't think they will feed right and I am definitely not going to shoot them.
I am a surprised at the results, I thought they would fair better.

[woodyz]

So basically the moral of the story as they say is; KEEP YOUR POWDER AND YOUR CASES DRY!!!

I know the testing is still ongoing but I'd like the members to come up with how to avoid this situation.

I have stored steel, brass, shot shells powder and primers in PVC with rice underground and under water for six months with no issues and every round worked as designed. I used rice with the idea that I could still eat it in a pinch as well. Metal weapon parts were stored in transmission fluid, in separate plastic bags from the non-metal parts also in rice. Storage always includes a small gun cleaning kit and a spray can of brake, shotgun or electronics cleaner which dries without residue.

So the difference here is I'm on a seven day key-hole mission wading through rivers and in the rain all the time. Doing nothing special with my magazines, ammo and rifle resulting in all coming down with a case of rust by the second day.

As I remember on a keyhole mission gun solvents and even gun oil were considered an odor problem just like sweat and food.

Keeping ammo and weapons in working order in the field is a matter of cleaning and lubing them at every opportunity which I think should/would/could be the first choice in a SHTF situation.

It needs to be part of the plan and enforced.

However, as in a keyhole mission (a sneak and peek while remaining invisible and not engaging) as I remember we used liquid/powdered graphite, every place you would oil, used graphite instead. Very easy to get too much, but very good lube for any moving parts even under water. No odor and one super glue sized tube lasts an entire mission.

I think I have some liquid graphite but if not I can get some and repeat the test, unless Will or cwi555 want to do it to make sure it follows the same events.

In the field conditions described by the post I think a daily breakdown, dry and clean of weapons, magazines and ammo should eliminate the problem.

Having said that I would think our current military people probably have input and maybe have something they used instead of graphite. I would think there are some differences based on heat and humidity, heat and no humidity and heat and water.

[Cwi555]

The concern with copper washed cases are not the same as the polymer. As you can see, the main body of the casing is holding up well.
It is the case mouth / bullet where the problem is.



On one part we have a galvanic corrosion cell that has been created. The electrochemical difference between two metals when combined with an electrolyte (water) has created an ionic transfer current as depicted in the above graph.

On the other part, we have crevice corrosion.


It has created a "differential aeration cell". I used tap water to simulate the same conditions Will would have in a salt water environment as humidity near large bodies of salt water typically have some chloride content. (another reason ocean air smells different to those who don't live in it)

A differential aeration cell (read crevice pit/corrosion) is created when the chlorides get underneath the protective coating (copper wash) The chlorides in this case came from the purification process of the tap water.

This also tells me the bullet alloy is not the same as the casing alloy, as the difference between crevice and galvanic corrosion depended on whether or not the corrosion initiated from the case mouth case junction from the copper wash being exfoliated, or the junction from the bullet to the case mouth from the same exfoliation. This also tells me the copper wash thickness is inconsistent as that is the only possible way these two conditions could have been created in the same round.

The red arrows are pointing towards areas of crevice corrosion The black arrows are pointing toward galvanic corrosion.

Either condition would be sufficient to make the rounds unsafe to fire for different reasons.

In the case of the crevice corrosion, the bullet could fracture the moment the chamber pressure gets up to peak. This could cause excessive drag in the rifling and build up of pressure to unsafe levels.

Alternately, the galvanic cell appears to be creating a galvanic weld. The case lip is being eaten by the cell as depicted in the galvanic graph above. That metal is being transferred to the cathodic side. and after some build up, is effectively seal welding the bullet to the casing using the anodic side (case mouth) to transfer the metal.
It is also corroding the metal under the case mouth as two of the rounds now display some minor swelling of the over all case mouth.

In all, the copper wash is no better than the polymer coated steel casings. If anything it is worse for the reasons above.

[northernbc]

so how would a fellow do with stainless firearms , and nickel coated brass ammo

[Cwi555]

Jun 6, 2012 6:29:23 GMT -7 northernbc said:

so how would a fellow do with stainless firearms , and nickel coated brass ammo

The stainless contains nickel. For that matter, all of constituent metals are very close to each other on the anodic scale. It should not be an issue.

[woodyz]

Amazed!

[stmtrn]

problem with nickel cases, they are real hard on reloading dies. got to use lots of extra lube. they are also brittle and crack much easier.

[rickL675]

Very good and vital information here. Thanks for posting this Will.

Also, thanks to CWI for his test and info.

[karatediver]

Awsome tests! Thank you for sharing. I've always considered steel and aluminum cases to be throw away target ammo anyway but in a long term situation it is good to know which will hold up better.