Shop › Springfield Armory Hellcat PRO OSP 9mm Image 1 of 1 Springfield Armory Hellcat PRO OSP 9mm $698.00 BARREL: 3.7"/ RATE-OF-TWIST: 1-in-10"/ CAPACITY: 17 + 1/ Add To Cart Added! BARREL: 3.7"/ RATE-OF-TWIST: 1-in-10"/ CAPACITY: 17 + 1/