Most likely due to a loose screw, specifically the loading gate screw. Many 336s have lever jamming problems and the majority are traced back to loose screws.
Look under the lever of your Marlin rifle.
100-1000 USD or so
1955
It's a version of the Marlin 336 lever action rifle that was made for KMart back in the day.
U is for 1961
Your serial number indicates that your Marlin model 336 lever action rifle was made in the year 1974.
Your serial number indicates that your Marlin model 336 lever action rifle was made in the year 1980.
Is this a trick question? I thought Marlin made the model 336. I didn't know Winchester made one.
The Marlin 336 RC 32 Special rifle with lever action is offered for sale at prices between $350 and $450. The price depends on the condition of the rifle and any accessories that may come with it.
The rifle is a marlin 336. Serial number is located on the lower tang under the lever.
1965, as indicated by the AA prefix of SN
your marlin is valued at between 200-350 dollars depending on the overall condition of your rifle.