Reference: MTA
Muzzle thread insert
FX Barrel end insert.
Caliber .177 or 4.5 FX 10332 - .177
Caliber .22 or 5.50 FX 10332 - .22
Caliber .25 or 6.35 FX 10332 - .25
Caliber .30 or 7.62 FX 10332 - .30