B's are found on 1937 - 1964 proofs and some business strikes from Philadelphia in years 1956 - 1964. The more rare ones are 1956 and 1964, although all are worth quite a bit in MS67. The only type C in the silver series is 1964 from Denver, and is also worth a big chunk. The type C is found starting with all 1965 quarters.
Type Bs are common in 1959 mint sets. I've also found a number of B quarters in the 1960 mint sets. I've heard that they have been found in other years as well but have not come across those.
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AWESOME ! thank you very much !!
Type C 1964d Washington quarter with striations on tail feathers
For type C, I always look at the tail feathers first. More detail on type C than typical 64 quarter. See the post above.
Which types/dates are worth looking for? I got quite a few silver quarters to look through.
B's are found on 1937 - 1964 proofs and some business strikes from Philadelphia in years 1956 - 1964. The more rare ones are 1956 and 1964, although all are worth quite a bit in MS67. The only type C in the silver series is 1964 from Denver, and is also worth a big chunk. The type C is found starting with all 1965 quarters.
Here is a type B reverse found in my 1959 uncirculated mint set. I have yet to find a type C reverse on any 1964-D quarters.

Type Bs are common in 1959 mint sets. I've also found a number of B quarters in the 1960 mint sets. I've heard that they have been found in other years as well but have not come across those.