Since the reeding is full and complete it's not a broadstrike. You'll need to measure the coin's diameter precisely with a caliper or micrometer, from east-to-west and north to south. If the diameter is the same as a normal dime, then that's what it is. If the diameter is greater, there are two possibilities. One possibility is that the perimeter was flattened in some manner outside the Mint. If the coin is out-of-round, that would support this hypothesis. The other possibility is that this is a rare "wide collar" error. Such errors occur when the collar is very worn and has expanded fractionally. It can also reflect the use of the wrong broach to produce the ridged working face of the collar or the use of a collar for a foreign denomination. A wide collar can also occur when two or more vertical collar cracks are present. I've only encountered a few wide collar errors among
US coins. One was worn and the other had four collar cracks, which allowed the collar to spread in all directions.
Error coin writer and researcher.