Fact – Touching the magazine of a many firearms, especially AR-15/M16/M4 –series rifles, has no adverse effect on functioning and has been PROVEN to be reliable and stable for decades.
FM 3-22.9, Page 7-3, Figure 7-5
“Once the basic firing skills have been mastered during initial training, the soldier should be encouraged to modify positions, to take advantage of available cover, to use anything that helps to steady the rifle, or to make any change that allows him to hit more combat targets.”
Certain detachable box magazine-fed, self-loading firearms may be susceptible to stoppages if the magazine is touched. The AR-15 series, including M16/M4s, is NOT one of them.
Since the introduction of Commonwealth-style International Combat shooting to the US Army in the early 1990’s, military teams have been adapting the good skills learned in National Match-style shooting to more freestyle events shot with rack-grade gear. Being a combat match, no alibis are granted. Any stoppage has to be cleared on the clock, therefore, equipment and technique must be reliable.
If touching the magazine caused stoppages nobody (at least not any winners) would use it because any risk of malfunctions would cancel the stability benefit. For about two decades the winning technique has been to use the magazine as a base of support when possible. From a tactical perspective, Mag Prone puts the shooter in “Helmet Defilade”, the lowest possible shooting position where the shooter’s helmet and muzzle are the most prominent things an enemy target can see.