Stretch Marks on an older crown cap bottle?

[moodorf]

I found a bottle in the woods today. It has these sort of....stretch marks? from top to bottom, all round. I don't believe they're scratches since they're pretty consistent throughout the bottle.

They even seem to swirl around at some points, back in on themselves.

There are similar swirls in my olive green blob top I have, but they spiral around the bottle as they head down from top to bottom. They're not just....straight vertical lines that occasionally make a "J" shape. But the thing of it is, this bottle has seams and a crown cap so it's definitely machine made, not BIM. So the lines/swirls are a curious feature to a newbie like me.

The bottom reads "7 48 4 3" with a maker's mark that is a R in a triangle. So, seems it comes from Reed Glass Company which makes sense cause I'm not too far away from where it was in Rochester. Given all these facts plus the lack of air bubbles in it, my semi-educated guess is, it's probably from 1948. So why the....stretch marks?

 

[Joelbest]

That's the first time i've heard the term "stretch marks " in reference to old bottles and i gotta say i like it a lot.