The only pellets I had to sight in with were Cph 10.5 grn. which I'm told are too heavy and might wear the spring to soon, I was told to use pellets in the7.9 to 8.6 weight area so I will obtain some this weekend FTS I believe along with some other brands.
The Mk III does not feel heavy to me, I would guess its a balance thing and its always a good idea to obtain the steadist rest available kneeling is good, resting against a tree if one is about, etc.
I see fun in our future!
Cheers