I have a mec 650 loader and I seem to be getting a lot of elbow and shoulder pain after loading about 6 to 8 boxes of shells. I sit kind of low and was wondering how high you have your bench.
My Spolar sits at 26 1/2" from the floor, my chair is at 21 ", everyone is different, hope this helps.
I reload both metallic and shotshell using progressive and SS presses. FOR ME . . . the higher my arm has to reach to pull the lever down, the greater the shoulder/elbow issues. I have two chairs, an adjustable stool and an adjustable drafting chair that is taller . . . and sometimes I stand. Which approach I use depends on which press I have mounted. Dunno if your experience is the same, but regardless I would advise altering your seated/standing height any way you can using whatever you have on hand until you find the heights that are best for you. Then adjust the bench or press mount or chair etc to keep your arm movement within the range that works best for you.
Had the same issue. Get a 9000 H and set up your seat for grabbing hulls and wads so your hands stay below your shoulders. You're shooting career will last longer.