Guns in build 4939 seems to be bugged

Basicly upon loading a world I revise so much debug messages that it takes a full minute or so of holding space to clear them. They all seem to be related to guns.
Sure enough the guns are broken, I would attach a picture if I could, but I keep on running to problems posting them here,

I have an open bugfix PR that fixes this. if you want to fix it yourself I posted the bugfix code here:
http://smf.cataclysmdda.com/index.php?topic=12669.0

I assume this is related to https://github.com/CleverRaven/Cataclysm-DDA/pull/16906
But I Am playing on 4939…
I finally got the images: http://imgur.com/a/31T7n
Yes I do have mods on, I have cataclysm ++ and many monster blacklisting mods, but none of them seems to directly affect guns.

4939 is derived from 4938, the difference is that ants were changed somewhat.

This is caused by JSON typos. It is easy to fix, as long as you use save instead of save as.

A bug fix has been merged. The new experimental is 4940