Is there really any difference in 100 yd. accuracy between these STANDARD rifles:

M1A (STANDARD no NM parts or modifications!!)
FAL (Standard)
PTR-91 (Standard)

Sights, none of the other two has the quality of sights the M14/M1A has. Even the 1/2 moa service grade sights.

Quoted: Sights, none of the other two has the quality of sights the M14/M1A has. Even the 1/2 moa service grade sights.

Want to run that one by us again?

The HK and FAL have sights that are adjustable finer than 1/2 MOA.  The only difference on the HK and FAL is the sight does not adjust out to 1200 meters with just a turn of the dial. All three are post front/ peep rears (note: the HK can be had with a V slot 100, and peep 200-300-400 rear peep as well)

In regards to the 100-yard limit, all will shoot about the same (2 MOA).  The Fal has an adjustable gas system, so it can be tuned to have less recoil than the M-14. The HK uses a delayed blow back action, so it will produce the most amount of recoil of the three.

Bottom line is they are all battle proven designs, so it just boils down to what tickles your fancy.
And yes, I do own all three types, and then some.

Yes, but KraigWY was probably referring to the fact that the m1a is the only one that has easily/quickly repeatable 1/2 moa adjustments (clicks). The HK and FAL can be fine tuned just the way you want them, but you can't quickly adjust them for windage changes since they have no "clicks" and you have to use a screw driver/adjustment tool instead. I too have all three, and although I'd put the "standard" model M1A up against the standard HK91 accuracy wise, a lot of standard FAL's only do about 4 moa where the m1a and hk will easily average 2 moa or less. Yes, there are some fal's out there that will do 2moa, but there are more of them that won't than will from my experience. YMMV.

all fine rifles, M1As with beautiful wooden stocks are magical though. I know first hand...  

No. I have one of each and thay all average right around 2" at 100 yards. The M-1A sights are easier to adjust, but the FAL is a 1\3 MOA thread pitch. The FAL goes out to 600 meters, but starts at 200. The H&K not only needs a special tool to adjust, but has no elevation markings on the drum. Once you are on target with the H&K at any of the known distances, the sight is calibrated. The main drawback is it only goes out to 400 meters unless you get the 1,200 meter sight.

Quoted: Is there really any difference in 100 yd. accuracy between these STANDARD rifles: M1A (STANDARD no NM parts or modifications!!) FAL (Standard) PTR-91 (Standard)