Make sure you have the correct gas piston in place. Light piston for 1 1/8 oz down, and heavy piston for 1 1/4 oz up. If you are shooting a target load with the heavy piston in, it will behave exactly as described. Mine is 6 yrs old and has never failed to cycle....not even once (with the right piston in place). I can shoot 7/8 oz loads all day long.
Failing that, check the gas ports. Used guns can have carbon build up, while new guns may have grease in the ports restricting gas flow. (A new Remington 1187 taught me that lesson). I use a small drill bit twisted by my fingers only to clean the ports. Do not use and power tool for this under any circumstances.