How old is this variation of the Optimus 300? I have aqquired a similar one but without the adjusting screw on the J-tube. Mine also lacks the enameled top hat. Regards Matti
If it is stamped 300 on the tank and not 300P then it is from the mid 1940s. The top cap on these was nickel plated brass and not the red enamel of the 300P. To my knowledge, the 300 and 300P never had an adjusting screw in the J tube. Optimus only started adding that with the introduction of the 350/550/1350/1550 models.