Lilja site info for .22wmr dropin barrel
Lilja site:
(Our .22 rimfire barrels are available in four different twist rates: 9", 15", 16", and 17". The 9" twist is available as a 3-groove only, the 15" as a 6-groove only, the 16" as either a 3, 4 or 6-groove and the 17" as a 4-groove only...