sight adjustment

[56 kodiak shooter]

I was shooting my 1944 ex-sniper today, all of a sudden it is shooting low, it was almost dead on at 50, maybe a little left or right but right on line now its shooting low same ammo, whats going on, could it be it was a bright sunny day, some people say lighting condition , has a lot to do with it, im baffle

[Longcolt44]

Let it cool down longer between sets. Shoot 1 or 2 others then come back to it.

[steelbuttplate]

Are you sure the back sight is staying locked in.? If dirty, rusty, or weak spring they can slide when you fire......You had it set on 100 M before? I've got one M-44 I have to keep on 200, also an SKS, same way........SBP

[walnut red]

Are your action bolts tight?

[56 kodiak shooter]

thanks guys I found problem, this rifle has shims in it , I took out to see if shot any better or worst, it shot about same just low