Kel-Tec has found that there has been a substantial problem with key-holing (bullets tumbling rather than spinning) from their new and popular PMR-30s. Consequently, they've temporarily halted production to work on a barrel redesign. They will be making those new barrels available to those who have had key-holing problems.
Blog post with some additional info
Original Kel-Tec news release
Blog post with some additional info
Original Kel-Tec news release