This is the proper way to hold and fire a rifle - note fingers of firing hand curled around stock.
Firing from windows, firing elbow is on ledge for greater stability. Kneeling riffleman has his firing elbow pointed directly to right, which is proper.
Firing a heavy weapon with a pistol grip results in this position. The elbow tends to point down. This applies to the M60 machine gun and German MG38 and 42 types.
Proper stance for throwing grenade, as taught in basic training.
Troops in combat tend to look disheveled.
Note grip on the stick grenade.
Elbow extended when firing rifle is the proper stance.
Note positions of kneeling riflemen here.
Unusual placement of legs for sitting stance, probably an old method. Note proper grip on rifle, firing elbow extended, hand wrapped around stock. Kneeling and sitting riflemen place the non-firing shoulder on their front knee for stability in aiming.
Fixed trench, WWII. Note sandbags and trench's zig-zig shape