These three coins has the same "S" mint mark design according to variety vista. There was only one design for these years. The pics show the condition of the coins. Why are these mint marks so obviously different?
The amount of wear will increase the width slightly as the base of a number or letter is larger than the top so the coin has some slack when separating from the die when minting. As wear and any physically force will flatten the lettering, numbers, inclding the mintmark. Thus thicker. Also die chips may be produced as the 'S' mm punch or any other may chips on the edges of the letter and may be between close portions. The S is known for chips that make it appear to be doubled or at least very different with connections between the upper loop and middle bar, or middle and lower loop. On uncirculated coins, the mint mark are usually same size for year/mint, unless it is an official change. Jim
The 1968 S appears as mms-004 trumpet tail, not mms-008 variety vista. The 1969 S appears as mms-005 ball serif inverted, not mms-008. The 1971 S appears as mms-007 sans serif , not mms-008.
