Several days ago, I stumbled upon this site and posted it... I'm assuming, 2015 came across this, or similiar information and tried to implement it in this game. This obviously doesn't explain the failure to hit when your at point-blank range (outside of lag causing your image of the enemy being several milliseconds to late...
For you gun fanatics, found this neat site
http://www.saf.org/LawReviews/PSharpe1.html
Some of the statements about the weapon....
Tests indicate that accuracy and penetration is very good, even at the longer ranges. A few feet from the muzzle the 230 grain bullet, tested on 3/4-inch yellow pine boards spaced one inch apart, ran 6 3/4 boards. At 100 yards it would plough through six boards; at 200 yards through 5 1/4; at 300 yards, 4 1/2; at the 400 mark through four boards, and at 500 yards it would still stumble through 3 3/4 [Page 1107] boards-sufficient to cause very unpleasant sensations in the body of a victim.
The accuracy of the sub-machine gun is decidedly interesting. File records of the Auto-Ordnance firm indicate that in a Mann rest test fired at Hartford, Conn., May 2, 1921, the mean radius using a Remington Standard 230 grain bullet at 100 yards ran 1.89 inches. At 200 yards mean radius was 4.92 inches; at 300 yards 7.63 inches at 400 yards it increased to 18.31; while at 500 yards it jumped to 20.45 inches. Accordingly, one can assume that the accuracy of the more or less spent bullets is quite uncontrolled at the longer ranges. This writer suggests that the effective range of the weapon is under 300 yards.