2017 F350

The inside corners are radiused more than some other receivers. This will cause the stinger to hang up if its edges are too square. The difference is very little and will probably be worn away after initial use, but inserting for the first time may be difficult.

I had similar problems before when I lent one of my stingers to a friend, but it was due to corrosion in the receiver tube from infrequent use.