The Effect of Modified Eye Position on Shooting Performance

Report No. ARL-TR-5518
Authors: William Harper, Frank Morelli, Samson Ortega, and Patrick Wiley
Date/Pages: April 2011; 50 pages
Abstract: This study was conducted as part of an Army Technology Objective (ATO) called Helmet Electronics and Display System - Upgradeable Protection (HEADS-UP) which is a program to leverage science and technology efforts to design a modular-integrated headgear system. This is one of several programs aimed at improving personal protection systems, many of which include adding facial protection from blast and ballistic threats. The addition of facial protection to helmet systems will likely cause a change in the way Soldiers cheek a weapon, directly causing a change in the natural position of the shooter's eye, thereby affecting the way Soldiers align the sights of a weapon when aiming. This study examined the differences in shooting performance for a Soldier firing a weapon using various eye positions due to changes in butt stock height and width. These eye positions simulated the effects of different helmet and facial protection systems, which may interfere with the normal cheek-to-stock weld between the shooter and the weapon, thereby altering eye position relative to the sight. The shooting tasks encompassed firing at targets between 10 and 300 m under time-pressure, using four different eye positions with 2 different sighting systems (iron sights and M68). In summary, hit percentage and shot radial error data showed that a 3 cm eye position offset degraded performance for both sighting systems compared to the baseline. However, with the M68 sight, shooting performance with the 1 cm and 2 cm offsets were not significantly lower than in the baseline condition, whereas the 2 cm and, to a lesser degree, the 1 cm offsets for the iron sight showed degraded performance over the baseline condition. Results from this study will allow developers to estimate shooting degradation that may be caused by facial protection systems that influence the normal cheek-to-stock weld.
Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2011