Sig Sauer ASP20

Quite possibly the sweat from hands has reacted with the finish.
I can be a bit of an acid old man lol.
The finish is faulty. It's forming over the finish not through it.
It starts where I break the barrel, but I noticed it on the metal rings around the barrel screws, had it this time. ( 3 days is the longest it's been unused)
Its got me a bit stumped. If it was a moisture thing, I'd be expecting the 2 crosman to react as well, they all live in the same place. Which brings me back to a sweat reaction as the crosman are both pump up, no real barrel contact with hands.
Not a issue had with tx200 in same case in same place.
I'm open to suggestions at this stage.
Probly have to do more research into the coating. I only have vague understanding of how it works from when I looked it up last time.

Gad think we had enough of quarantines.
It could well be the sweat from hands, but that was wiped and oiled before going away.
The 1322 which sits in the same place, except with just a towel wrapped around it is sweet as. That thing use to surface rust like mad till it had been oiled a dozen plus times.
I've got a packet of moisture absorbing crystals in the sig hard case too.
Guess I'll just keep oiling it Hooe it stops.
Maybe I should write to sig, might be able to get a new barrel in .22. I wish.

Are you serious...!! Wowzers looks like it's had a bath in sea water before being stored...!

Poppy cock! If your at your technical limit, then it's time to start fine tuning.
( Though from a hunting aspect, those are both killer groups.)
A spring change to something that will lessens the kick and by default fpe.
Maybe a small tweek in your hold?
Its really so close hole on hole it would be a shame not to find a way tighten it.

Weight will play part. There is a relationship between the extreme weight ranges and head size. I've found.
Flyers should cut right down. It also gives you time to check for head and skirt damage.
Skirt damage can be a big thing in some tins.
Actual roundness of the head is interesting too. I found a few pellets that measured differnt on one side to the other. The worst was 4.50mm one side and 4.46mm on the other. I imagine that would affect flight chararistics as well.
Skirt damage is a biggie with me I'm pretty hard on my judgement of it, it takes very little to lift the skirt to high for effective seal.