I discounted the FA factor because of the request was for civilian use. If FA is a factor, the H&K would be the way. For the M14, FA was not very useful and very very hard to control.
Also there is the SR 25 (Stoner), The big negative is the Price. About twice as much as a M1A1.
The G3 is very recoil friendly, but does have it's own unique problem in a dusty enviroment, the recoil blast. Also a little hard on the cases if you reload.
Hollis:
I don't think FA is a big factor, since it is for a civilian's use. As you point out most all FA rifles in 7.62 caliber, suck in FA mode.
Although as I recall there was a FA heavy barreled M-14 (With a different stock.) around at one point. I think the idea was to sort of make a replacement for the BAR in the Infantry Rifle Sqd. (IMO, this was a failed attempt, as the BAR was a better weapon in that role.) I used the BAR in combat in Korea. It was my favorite weapon there, next to the M-1 Garand. As a matter of fact, I think there is also a semi-auto version of the BAR sold on the civilian market in both 30.06 and 76.2. ;)
Yes the G-3 Battle rifle and the HK 91 do handle recoil a little better and your right, they both tend to put a crease in the brass when ejected. Many also complain about the short stocks on both the G-3/91. I also had the trigger worked over on my HK 91. It's more like the M-14 trigger now, which I did like, as it was like the M-1 Garand's trigger.
The other thing I liked about the HK91/G-3 was the HK clip on scope mount. I have both types the HK 91 has the military Zeiss Range finder variable sniper scope and the HK 93 has an Aimpoint Red Dot (Older version) mounted on the clip on. They both kept there 'zero' when taken off and put back on. (I also kept a Redfield wide view 3X9 mounted on a 3rd HK clip on mount for use on the HK 93.) I used the HK93 when I was leading the SWAT team, etc.
It is my understanding that finding a true HK91 or HK93 is difficult and expensive now. I thought they were both VERY good weapons for civilian usage. I preferred my HK-93 over the AR-15s, even though it was a bit heavier. (Note: At the time many of the currant M-4 type weapons and 'goodies' were not invented yet.)
When I did entries I used the HK collapsible stock and the regular fixed stock when on the security element or general use.