All Machine Doubling. The only area to search for doubled dies is on the central devices on the States and AFB quarters. To see where to look for doubled dies on these, check out this link to find out where to find the doubled dies on each years coins. On the obverses, it is mostly the earlobe area 99.5% of the time.
States:
http://doubleddie.com/179401.html
ATB Quarters:
http://doubleddie.com/719755.html
Again almost always the doubled dies are on the central areas on these quarters. Take a look and see what you are missing on these coins.
States:
http://doubleddie.com/179401.html
ATB Quarters:
http://doubleddie.com/719755.html
Again almost always the doubled dies are on the central areas on these quarters. Take a look and see what you are missing on these coins.





























