I started Basic with the M-14. went to the M-16, Bought my own Browning semi auto and carried it, LT FO, but then I had a whole Infantry company to guard me
I have used a ton of weapons and really like my Mini-14 that was converted to a folding stock and shortened two inches one inch muzzle and One inch chamber then rechambered and re-crowned with a four power Burris scope it worked well in my role a scout on SAWT.
I have an m1a1 with scope and I assume it is very similar to the m-21 in service. I like it a lot and have made one shot kills of Elk here in Colorado at three hundred plus.