So while assembling M77 magazines we found one that was completely unserviceable, so we did a rust test vs our old standard finished Vepr .308 magazine also unserviceable.
So here are the results of three months outside. All of October, November and December these sat outside. I flip the magazines every few days to allow all sides equal exposure. The block is set at a low angle to allow eventual drainage and drying. We started the test by wiping the black nitride magazine with alcohol to remove any oil coating. The bare steel is marked 9-30 the day the test started, I intend to leave these out one year.
Black oxide on left Black Nitride on the right. Steel plate below is marked 9-30 which is the day the test started.
Showing the pair of steel jacket round loaded at the start of the test. The rust stains inside the magazine wipe off, finish is still holding out.
You can see the damage to the feed lips, that is why this magazine was used.
You can see the rust washed into the magazine from the top and residue was left on the bottom, again it wipes off.
The spring seems to be rust free still, the rust on the follower and retainer plate is from the ammo.
Follower with the rust wiped off.
I started a new pair of magazines on 1/1/16 one steel G3 magazine and one of our new style Vepr .308 magazine. G3 is already sprouting rust scale.