| THREAD SPECS | MAJOR Ø | PITCH Ø | MINOR Ø | |
| 1/2-28 UNEF-2A (MODIFIED) | .4989 / .4924 | .4757 / .4737 (MOD) | .4563 MAX | Download Barrel Thread Guide |
| 5/8-24 UNEF-2A (MODIFIED) | .6238 / .6166 | .5967 / .5947 (MOD) | .5742 MAX | Download Barrel Thread Guide |
| 3/4-24 UNS (MODIFIED) | .7488 / .7419 | .7217 / .7197 (MOD) | .6992 MAX | Download Barrel Thread Guide |