I would agree, those types of weapons seem conducive to long term storage if prepared properly...
When they mentioned “tire” in the article, it probably meant a “tube” that was sealed at both ends to reduce water or other corrosive seepage that would be a problem...
Why they put it by a “road side” is beyond me...
Probably thousands of little cashes like this all over the place over there...
Or when they find the buried remains of the lost Napoleonic French army that died in the Egypt wastelands ....