Internet BS Alert!!!
However, I've heard from long-range shooters that a M1 will be good to 1000yds while an M-14's 7.62mm will play out just past 800yds. How many of us actually shoot that far? Don't know, but wouldn't it be fun to try?
Yeah, yeah, heard it here and heard it there. Well, what I read was based on highpowered statistical analysis of literally thousands of shooters at Camp Perry right after the M14 appeared there in accurized form. Anyone can verify in various [usually September?] issues of _The American Rifleman_ just about every year through the 1960s.
1. The 173-gr Match ammo was measurably more accurate in 7.62 x51 M118 than was the M72 in .30-06, almost every year if not every single year.
2. Shooters' scores tended to go up when they switched to the M14.
3. Shooters tended to get a few more points offhanding using the M1, believed to be because of a more muzzle-heavy weight distribution. Shooters picked up MORE points at the other stages in the course b/c of better overall accuracy.
Now, regarding this "hits harder" nonsense--I HAVE fired both at extended ranges and your M2 Ball in .30-06 is going subsonic at only 600 yards. I've pulled targets for the poor sods shooting that stuff and it wasn't pretty. Anything more than a 5 mph breeze with any variability and they were lucky to hold the 7 ring, shooting prone slowfire with a sling. M80 Ball in the 7.62x51 is still supersonic and hits harder at longer ranges. I don't recall where it crosses over and catches up with the 100 fps and 3-4 gr bullet weight "advantage" of M2 Ball, but youse wit' ballistics programs can calculate that for us.
With 173-gr M72/M118 Match ammo, both are good to 1000 yards, but the M118 is virually guaranteed to group better, often a difference on the order of 1 MOA groups vs. 2 MOA groups. In my experience, it was more like 1.5 MOA in the M1 and 1 MOA or better in the M14 type rifle, with Sierra Matchkings.
The M1 *can* be topped off to 7 rounds easily, but it's a clumsy trick. Hit the "puke" button with your right thumb and your palm over the bolt. Keep the ammo and clip from coming out. Pull the oprod handle back until it locks, but just to keep pressure off your hand. Stuff rounds between the feed lips of the clip like it's a bolt gun's internal mag. (Stuff too hard down and your will unlock the oprod and it'll want to go forward.) Thumb down the clip/ammo with your right thumb and pull the oprod handle back 1/8-inch or so with the edge of your hand. You will feel the clip latch engage. Remove Thumb. Re-check that thumb is REALLY removed! Let oprod handle go.
To top with 8 rounds, it takes much more diligent holdback of the oprod with the edge of your hand because the oprod will, WILL be forced unlocked before you pull it back, and it takes a lot more thumb to cram round #8 into the clip.
As far as an accurized M1 in 7.62 being more accurate than an accurized M14 type in 7.62, well, I've never seen any large-sample studies. I do, however, believe that bedding on and M1 will tend to last longer than on and M14 because of the larger bearing surfaces on the receiver legs. However, proper care seems to make that not matter, since the barrel will shoot out before the bedding lets go, and you typically have to re-bed after putting in a new barrel anyway.
I'd take prone slowfire scores at 600 yards, across the Palma, and at 1,000 yards as evidence of which rifle shoots more accurately.
As for discounting bench accuracy with this tough trash-talk about "combat"--
Bah-HUMBUG!!! So you think that quick and dirty aiming at speed, when you cannot reliably hit better than 12 MOA, negates the utility of accuracy?? Here's where I'm at. If I take a fast shot at 300 yards which breaks at the neck of my target instead of COM, which will serve me better--the 2 MOA [insert your choice of "combat" gun/"combat" ammo combination], or the 1 MOA gun/ammo combo that's available in the M14 or HK 91 style of rifle if fed good ammo? If you'd be plenty happy with a 6-inch area where that shot *could* hit, instead of a 3-inch area, you might be interested in this bridge I have for sale back east....you'll get a LOT of income from those toll fees you can charge!