I hate to rain on the M14 love fest but......
The M14 was never that successful of a weapon. It was plagued with production problems from the start. We never did produce enough to equip the Army. It was a major scandal during the Berlin crisis (not the airlift, but in about 1960 when the Soviets once again closed the highways) that our forward deployed units, those at the tip of the spear were still armed with the M1 even though the M14 had been the "standard" for about 4 years.
Some units never did see the M14 and went right from the M1 to M16A1. When the NATO countries were looking for a new standard cartridge and rifle in the early 1950s, everyone but the US wanted a small caliber. The US wouldn't budge off of .30 caliber so the Brits dropped the Enfield Bullpup (looked surprisingly like the early SA-80s) and the FN-FAL was upscaled to take the 7.62x51 round. The FN-FAL went head to head with Springfield's M14 to see which would be the new US service rifle. The M14 won in what many considered a rigged test. Basically the rest of the free world adopted some version of the FN-FAL and we adopted the M14. By about 1973 the M14 was pretty much gone from Army inventory and everyone was carrying the M16A1. The US had the small cartridge that it had so opposed in the 50s. NATO had the 7.62x51 cartridge the US Ordnance Dept. forced on them and it soldiered on until the mid-80s with the rest of NATO.
Nodakmarine,
I think the M25 is a commercial designation by Springfield Armory for an M1A variant. To my knowledge the only place in the Army (besides maybe some SOF arms rooms) you'll find the M14 is in the Old Guard, the ceremonial unit that serves DC. The Army is still discussing the designated marksman concept and from what I've read in the professional journals, takes a totally different view of the concept then the Marines.
I voted for the M16 which has served me well for 27 years. Next would have to be the M1, then the 1903 Springfield. I have an M1A and really enjoy it, but as far as history goes, I think the M14 is just a bump between the M1 and the M16.
Jeff