Tips for swaddle transitioning

Megan
My son will be 5 months at the beginning of February and we still swaddle him at night. He's not rolling over yet, but he's close and I know we can no longer swaddle him once he does.
We've started to try swaddling with one arm out, but he only makes it an hour or two before he wakes himself up by pulling out his pacifier. 
Any tips?