Corrosive primers - Milsurp ammo

[Tempest455]

Great article on this topic:

7.62mm ammunition primer corrosivity test

[ttocswob]

Thanx, good info. The results from commercial Wolf are eye-opening, to say the least.

[peejman]

An interesting study, though I'm suspicious of some conclusions that might appear obvious... Don't jump to the conclusion that your barrel will look like that 2 weeks after shooting Wolf ammo.

There is no "control" identified in the study. Perhaps that's what the Wolf (a known non-corrosive primer) represents. If you do assume the Wolf is the control, then it is the baseline against which all the others should be evaluated.

I think the fact that the Wolf showed some corrosion is due to the method of application, which has little correlation to actual use. You don't blast a flat plate with combusted primer products inside a barrel. The size, velocity, and hardness of the combusted primer particles likely has as much influence on the apparent amount of corrosion as anything else. When those particles hit the flat plate, they may create micro-pits in the surface due to impact. Those micro-pits are where corrosion begins. The presence of corrosive residue would accelerate the pitting, but the impact gave it a big head start. A primer that produces very hard particles will pit the surface more heavily and may show more corrosion for that reason alone and have little to do with how corrosive the residue is.

It's also hard to tell if the plates themselves have corroded or if its the impacted residue on the surface. You'd have to look at the plates with a magnifier and clean them to tell what's really happening.

[I_Like_Pie]

The study was great in intent and I am sure very fun to perform, but like peejman I am not sure if it accomplished much with respect to a controlled study. He left a piece of steel out in the elements for 14 days after blasting it with a nasty primer.

Do people consider water corrosive?...let it sit on one of those plates for 2 weeks and see what happens.

[Tempest455]

The study was great in intent and I am sure very fun to perform, but like peejman I am not sure if it accomplished much with respect to a controlled study. He left a piece of steel out in the elements for 14 days after blasting it with a nasty primer.

Do people consider water corrosive?...let it sit on one of those plates for 2 weeks and see what happens.

I agree with many of Peejman’s comments about the flat surface, mico pits etc. Also a plain steel control was needed.

With regards to letting them sit outside: By letting the plates sit out for 14 days, his was a simple method of replicating a corrosion test. ASTM salt spray tests basically just speed up the corrosion process by using elevated temp, humidity and corrosive salt. By blasting the plate with a corrosive salt (as in this test), leaving them all outside under the same conditions would just speed up the oxidation process.