I am making final preparations for Zim in Aug. I not used to shooting when it is very hot. Is it unusual to get vertical shot groups when it is hot 85-95 degrees and 70-85% humidy? Both guns that are doing this the 416 is worse then the 375. Both guns are in plastic stocks and freefloted. I shoot 3 shot groups, I takes me 2-5 min. to shoot a group. The groups run perfectly vertical between 1 3/4" to 4 3/4" it seem that I have something going on as the are so strait. Very little difference side to side. This makes me think that these guns could do much better. Any incite would be good.