Speaking on EBRs-
They suck, period. All the ones I saw were 3-4 MOA guns, aka couldn't reliably hit a head size target outside of 200m.
Head shots are what you need in the outside-of-CQB-range marksmanship game. Bad guys don't offer full exposure/broadsize target presentation- the ones that do are already dead.
600m headshot on a 12" head is a 2 MOA target, now figure for winds, ranging error, and stress- I would want a 1 MOA .300 win mag at a minimum to feel confident in a first round hit.
Which brings me to another point- first round hits. You usually only get one try. If you get pretty close once, close enough to call a correction, the dude is generally going to move to find a different place to stick his head out of- especially in an urban environment.
As for the 7.62 argument- I wouldn't want to carry a gun that weighs twice as much and ammo that weighs 3x as much to only extend my super sonic range by 15%. That's bad math, even by common core standards.
ETA-
Honestly, I don't think the M14 is nor ever was a good weapon. Sure, Camp Perry and NMA M14s are great, but the ones they field as EBRs are junk. I think the Army did a good job not sending them to Vietnam, and are making a sound choice today not reintegrating them.
You can't realistically do CQB with a scoped M14, a match quality M14 would rival an M2010 or SR-25 in cost, and the user still wouldn't have sufficient training.
3-4moa with M80? My experience with the M14's, the EBR's, the SDMR, and the M110 were very different.
1) I carried a rack grade M14 in Iraq, shitty beat up wood stock, duct taped field expedient cheek piece, shitty Springfield optic mount, topped with a shitty MK4. With M80 ball yeah you had a pretty nasty group, use m118sb or lr, and that gun was 1-1.5 MOA all day. I had an issue with the mount, so I just zeroed Irons and kept rolling with it. As long as I did my part is was more than capable. Now that was 2003-2005, how beat up they are now (Joe and his fucking dental tools on the crown of the muzzle), I'll cede to your wisdom.
2) The EBR is a sub-moa gun, I've taken them out of the box, grouped and zeroed them, and taught 17 classes, specifically on that weapon. Now I personally fucking hate the stock they put on them, but its got a NM barrel and trigger. So I'm honestly confused with your responses.
7.62 argument) I agree with the weight comments, but its the NATO round. I'd much rather a 6.5Creed or the like.
M110 is a over priced POS, another one I unboxed and group and zeroed, 2.5moa all day. My cheap Armalite SASS with a Noveske barrel is sub-moa all day long. I can't believe the Army took it in the ass on the M110 the way they did. Not against a semiautomatic precision rifle, actually for it, but think the Army could have done it cheaper and better.
As for the M14's, we got them, there paid for, rebarrel as needed and give soldiers a case of M118 and a few days on a KD range every couple of months and its done. I'm all about new cool shit, but just like the "pistol" the Army gay's the hell out of it, makes a several million(billion) dollar project out of it, and you end up with an ACU pattern uniform in the end. I'd rather spend the money on bullet's.
That said, the SDMR is basically an M16A4, with a NM barrel/trigger and free float rail. With mk262, it will shoot 1(sub) moa all day long, its cheap, easy, no retraining, and same same, case of ammo, KD range every few months and done. But it lacks the range/lethality at distance that a heavier round would offer (6.5 creed would be a good round IMHO).
As for the headshot's, I fully agree, and wonder where you were when I preached that same shit years ago and got told to shut up and color. lol I also agree with trying to CQB with a scoped M14, and would say the same for M110, SR25, etc. SDMR, toss a 45degrees off-set mount and Aimpoint micro a collapsible stock and you're GTG. But anyway this is getting too long, I didn't and I'm not saying you are wrong, things are always changing, but thought i would voice my much different experience with regards to the M14 & EBR.
$.02
