(http://i.imgur.com/xaExqHo.jpg?1)
(http://i.imgur.com/e6gxiGP.jpg?1)
Confirmed, i shot twice every target (on screenshots) and multiple times for testing.
First target 100% chance with lazer rifling. (always hits with 4 bullets)
(http://i.imgur.com/9uZNKPO.jpg)
Second target with 59% chance to hit (always hits with 4 bullets)
(http://i.imgur.com/6KjLd8u.jpg)
Third target with 0% chance to hit (always hits with 3 bullets)
(http://i.imgur.com/iYgnRGQ.jpg)
In the end, your maximum range is almost your effective range for this gun, since the spread of it is so small.