When did Marlin Introduce Micro-Groove Rifling?

[BarkeyVA]

I just bought a Marlin Model 81-DL this week. It has a conventional forearm that Marlin apparently used between 1945 and 1957. My rifle also has conventional rifling with 6 grooves.

I have a reprint of the 1954 Marlin Catalog. It describes Micro-Groove Rifling, and states, "This new and novel type rifle barrel is now available on Marlin .22's."

Was 1954 the first year for micro-groove rifling? If so, then that would indicate my rifle was likely made between 1945 and 1953.

[Regnier (gunrunner)]

BarkyVA;

1954 would be correct for the Marlin .22 caliber rifles. Marlin then made the Micro-Groove rifling available to all of the product lines in 1956.