are they still available?

I have been collecting for 70 years and inherited about 800 pennies. I have finally decided to catalogue my collection. You know, I have often wondered this same question. We must be awful dumb on this subject that nobody wants to answer us or it is so obvious. I would have thought there are tons of...

Finally cataloguing my coins after sixty years and I have a numerous (15)1997 pennies that in various grades (what I would estimate at EF - MS 65), that are rippled or pebbled. Is this a common thing. I don't see any listed.

I've been in is for a long time but I'll be damned if I can figure out what causes these. They are on quite a few of my MS pennies. Some pennies I would even rate at MS65 except for this. Can anyone help out?