Umarex T4E HK416 help

Hello to the forum, i'm Massimo from Italy and i dont speack german so sorry i'v to post in english hope is not a problem. I just bought an umarex hk416 T4E and i'm so upset by the accuracy because i cant keep the spread of the bullets (powerballs or rubberballs is the same!) in 20-30 cm at 10 mt.
From 15 mt it start to be quite impossible to hit a targhet of 40x40 and around 20 mt on a targhet of 60x60 is a miracle if i hit it on or 2-3 times on 14 shots of the magazine.

First i'd like to know other owners of this gun if have the same explerience, and i'd lke to know if the other guns of this serie are the same (tm4 and tm4 ris).

And last i'd like to know if there is something i can do to modify the gun and imporove the accuracy.

Grazie and Ciao to all..;)

i'v havent used the blue balls but i just ordered them on internet. I'm using the umarex fast balls (the rubber darck grey ones) and the umarex battle dust powderballs (yellow/red) do you have this gun you too? how long can you shoot with an accettable accuracy?

hei i confirm the best accuracy of the blue rubber balls, the difference is big, now finally i can hit the targhet at 20 mt, 100% of loader 14 shots, with a 50 cm accuracy and 10 cm accuracy at 10 mt...now is possible to play..:D so...blue balls!