Wanaxit,
I will try to answer your questions in detail, but you must help me by finding someone who is technically fluent in English to help with the translation. Google translate is good for basic translation, but when you are dealing with technical issues, you really need something better.
It is good that you are using 4895 powder. That was the original powder used in WW2 Ball ammo. It is very flexible and has worked very well in the M1 for 70+ years. My personal load is 46.5gr. with a 155gr match bullet. This is slightly less than full power and has won matches for me. If you are looking for best accuracy, use match quality bullets. 150gr. FMJ bullets will be OK for general use.
Here are two articles that may prove helpful to you.
This one is instructions for tuning the issue M1 to make it shoot better.
https://www.milsurps.com/showthread.php?t=37215
This one is how to improve the trigger.
https://www.milsurps.com/showthread.php?t=37213
Read these and let me know if you have more questions.