CAPT OF A DC9-50 MADE A 30 DEG BANK TURN AT FL350 AND EXPERIENCED A BRIEF ACFT BUFFET AND WAS NOT SURE IF IT WAS CAUSED BY INSUFFICIENT AIRSPD OR TURB.

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WHILE INBOUND TO MEM ON FLT WHILE LEVEL AT FL350; I MADE THE TURN TO JOIN THE STAR ARR AS I PASSED OVER POCKET CITY VOR. CRUISE SPD WAS ABOUT .760 OR .770 MACH. I HAD BEEN EXPERIENCING INTERMITTENT LIGHT CHOP. TO MAKE THE TURN; I USED THE HDG BUG AND AUTOPLT; WHICH RESULTED IN A BANK OF ABOUT 30 DEGS. WHEN IN THE TURN; I FELT ABOUT 3-5 SECONDS OF WHAT I THOUGHT WAS MORE LIGHT TURB. JUST AS THE DESIRED HDG WAS ACHIEVED AND THE BANK RETURNED TO ZERO; I REALIZED THAT THE 'LIGHT TURB' I EXPERIENCED SEEMED SOMEHOW DIFFERENT THAN THE EARLIER TURB. I THINK IN RETROSPECT THAT I EXPERIENCED NOT 'LIGHT TURB' DURING THE TURN BUT INSTEAD A BUFFET. FURTHER; I THINK IT MAY HAVE BEEN A HIGH SPD BUFFET; THOUGH I HAVE NEVER EXPERIENCED A HIGH SPD BUFFET BEFORE AND I AM THEREFORE NOT CERTAIN I KNOW WHAT ONE FEELS LIKE. IT FELT LIKE A SLOW SPD BUFFET; BUT WITH A HIGHER FREQ TO THE BUFFETING. NO ACTION WAS TAKEN ON MY PART BECAUSE OF THE SHORT DURATION OF THE EVENT. BY THE TIME I BEGAN TO SUSPECT THAT IT WAS SOMETHING OTHER THAN LIGHT TURB; IT HAD ENDED.