In the Army they taught me to shoot with an M16A1 (1975/76). In the spring of 1976 I shot an M14 and fell in love with it. TRW 1490317 (you know how it is, you sign it out and back into the arms room every day it's hard to forget the serial number, even after 40 years).
Shot it at Ft. A. P. Hill and knew I had to have one. I've had that M1A since 1978, or early 1979. One month's pay for an E4 in those days. Seems like it was about $495. Mine never did shoot to suit me. Got a lot of experience testing different powders and bullets and doing stuff like weighing bullets (waste of time weighing Sierra match bullets), weighing empty resized and trimmed cases (never figured out if that was worth it), outside neck turning brass to get uniform neck wall thickness, playing with bullet seating depths, using motor mica to make resizing the inside of the neck less stressful on the brass, weighing powder charges, etc., etc., etc.
Killed all my deer with it (one shot kills) in the WV mountains (when you're in your early to mid 20's an M14 ain't too d__n heavy. As one of my wife's uncles said about his Korean War experience with the M1 Garand, "I only remember two things about the M1. It was heavy and it killed good, it killed real good." The M14/M1A is that same story. The rifle goes bang and deer drops right there. Never had one run, never had to track one down (did that for a buddy one day, what a pain in the butt.)
Then I bought a darn rack grade Greek return M1 Garand at the CMP North Store and it shoots rings around my M1A. It's what put the M1A in the safe. The rack grade is butt ugly, but man, with that LMR barrel it sure does shoot good.
You know, they've been "working" on the cartridges for the M16/AR15 since the 60's trying to make them more accurate at long range, make them penetrate better, make them kill better, etc. The M1, M14, M1A have been using the same bullets for decades to do all that (well, maybe not match accuracy but did you ever read about the Marines shooting across those 800 and 1,000 yd. wheat fields in France and wearing out the attacking German infantry? They killed/wounded so many Germans with off the rack iron sight bolt action rifles and issue ammo that the German commanders told their higher command that they were facing a "battalion of snipers."
A lot of people don't "get" the M1A (or the M1 Garand) but there's something there you just don't get when you handle/shoot an AR15.