Hey Tim,
I'll try to give you a few pointers, advice, and personal experience with the M1A(M14). As a retired Master Gunsmith, I have retained all the fond memories of the firearms I feel are the best in the world. First, IMHO, there is no combat rifle that can hold a candle to the M1 Garand(30-06). It was the finest combat weapon a soldier could have, with a kill range over 1000 yards. Its only complaint, by very few, was its weight of 11+ pounds. Only the "little" guys really complained, and very few of them.
The M14 was an improved M1 Garand receiver, modified for a detachable magazine, and shortened and lightened. It was chambered for the 308 Winchester (NATO standard). It is also gas-operated as the Garand. The M14 would be my second choice as a combat weapon. The 308 is also capable of a kill at 1000 yards, but the ballistics are diminished more than the 30-06. The 308 Win. is an unbelievably accurate cartridge. Of course, handloads make it even more accurate.
The M1A is the civilian version of the M14, and is closed bolt design for semi-auto operation only. The M14 is an open-bolt design for the selective feature of full auto. The rifles are identical other than that feature.
I used to shoot, back in the early-mid 70's, at Williamsport, Pa in the 1000 yard competition. I have a National Match M1 Garand I got in '69 from the DCM. Still shoot it. It will still put 5 rounds in a 1/2" hole at 100 yards with the original peep sights. I have a healthy supply of 30-06 National Match ammo I got in '69-'70. The M14 (M1A) will also print groups like that. What was fascinating back then was watching the 308 bullets at 600 yards in flight on their way to 1000 yards. You could see them as their velocity was really falling off, but not their inherent accuracy. We were looking thru 60X-100X spotting scopes to spot the target hits.
Anyway, I can only suggest that if you have a hankering for a rifle such as the M1A, by all means, get one. It will never let you down. As with all firearms(and welding), practice makes one better and better. If you have the option to handload your own ammo, you will see how the M1A will really shine with accuracy. Remember though, the M1A, like the M14, is rifled for the heavier 160+ grain bullets, and they love the 168 grain Matchking bullet.
Ok, youngster, hope I helped you a bit. The smart investment is the cranial investment with research and any literature on firearms and ballistics. Feel free to query my residual knowledge base, as I have fairly well retained the firearms/ammunition information I acquired in 30 years....Keep us posted....Good Luck...Denny