TargetTalk

As a "newbie," would someone help me with these questions:
(1) Will the placement of the sliding barrel weight (on an air pistol) affect group size?
(2) re 4.49mm vs 4.5mm pellet size for an air pistol: is this really important?
(3) How does one go about finding the best shooting pellet for an air pistol?
Thank you for your help !!

As a "newbie", don't worry about the barrel weight.
Shoot any of the pellet sizes 4.48 to 4.51 and don't worry.
After you can shoot better than 93 out of 100 then worry
about pellets, learn how to shoot first.
Just use good quality pellets made for target shooting.

I agree with David. As a "newbie" the difference between 4.49 and 4.5 does not mater. The pellet brands available to me are mostly the European brands. RWS, H&N and JSB. Would be happy to use any of them in competition. I shoot around 570 level and I cannot tell the difference between a pellet that goes into a test target sized group and one that shoots a 3mm group. Testing is waste of shooting time.

"Testing is waste of shooting time."

I second that emotion, but testing has saved me considerable cash.

From what I understand, the accuracy variation between brands of match pellets is smaller than the AP hold.
What I mean is look at the small size of a 10m AR target vs. the much larger size of the 10m AP target.
So testing makes sense for the small AR target, but may not make much difference for the larger AP target.
However, if it will make you feel better, that in itself may be worth it.

Personally, I bought a couple sleeves of the Vogel Sport/Training pellets.
Cheaper than the match grade pellets, and good enough for me, at my level.