TargetTalk

I do 2 kg weight pack training for an hour often. (the training that you have 2 kg pack hanging on the barrel and remain aiming for 5 min.)

Everytime I finish the training and start shooting, my left leg trembles a lot. As a result, I get to shoot 9 and 8.

Does anyone know why I am having trembling left leg after the 2 kg weight pack training?

why the weight training?

Weight training causes trembling.
weight train after shooting...

You need to train with the rifle in the same condition it will be used in matches. If you need strength training see a personal trainer and explain you are focusing on the needs of rifle shooting (core strength).

Most likely you currently have very contracted muscles in your legs while using the extra weight on the barrel, and when removing the weight your leg relaxes and the tremors begin. You may be able to get rid of the tremors by strongly contracting the leg muscles for a short time, then relaxing them.