I've heard that young soldiers at Ft. Benning are being taught a tripod, elbows and magazine with legs spread straight out instead of leg being drawn up. Also has the use of the sling as a stablizing unit been emphasized lately.
Re: How has body armor changed prone rifle technique?
The current official position of the United States Army Infantry Center and School is there is no problem with the M16 rifle, body armor, and helmet regardless of the Soldier's build, height, or gender (despite official findings back in 1985 that the M16A2 is too long).
The G3 of the US Army Training Center at Fort Jackson, South Carolina reported in 2005 he was using way more ammunition to qualify Soldiers through basic training, averaging 75% "Go" on the first try through, with most Soldiers qualifying by the fourth try.
Almost 50% of Infantry trainees failed on the first try through.
The US Army G3 tasked Picatinny Arsenal to research a collapsing-stock option for the M16A2 and M16A4. After four years of screwing with the problem still nothing.
Bottom line -- Infantry School tells short troops "Work around it."