Guys, I need some advice as a new FAL family owner.  I recently purchased a complete (not kit) STG 58 Carbine (18") from DSA, while ordering it I asked: "what kind of accuracy to expect, is 2 MOA a reasonable expectation?", and was told "oh, absolutely". Good to go, order made, carbine delivered. Nice looking, trigger on the heavy side, but I can manage. I install a Redfield 5 Star 6X on an ARMs #3 mount, along with a DSA hooded apperture rear sight as a backup, and off to the range I go, high hopes in hand, along with a selection of LC ball, M 852 match & M 118 LR ammo on board.  First couple of shots, good to go, grouping a tad left, 9's at 9:30, adjust right, an 8 out at 1:00, followed by a 7 at same, followed by a 6 in that area as well. In other words, vertical stringing along the order of minute of paper plate accuracy at 100 yds, a wee bit off of that 2 MOA spec. Changing ammo (of course) had no effect, neither did shifting to irons. To establish a baseline, let me add that I have points towards Distinguished, earned with the M14 as well as the AR, so this ain't my first trip to the rodeo. I started searching on "vertical stringing" and have discovered that this is not at all unusual for a FAL series weapon to exhibit!  I called DSA and was told to test it by: shoot with mag installed but empty, single load only. Remove sling swivel and shoot. Try different ammo and repeat above.

 Guys, I thought they meant 2"-3" MOA WITH a loaded mag in place and utilized, otherwise I've got a really cool looking single shot, or a really inaccurate semiauto (that STILL looks cool). Is this "the deal" with FALs? Is this what they all do? I need to know, preferably from those that have real experiance with these rifles, and also possible causes and fixes as well.  To me, an honest 2"-3" MOA would be acceptable, but not 2" X 10"! Let me know!

R/OMC

Vertical stringing is common with F A Ls, but it isn't usually as drastic as what you described.
If you have those steel hand guards, then ditch them as soon as practical and replace them with surplus synthetic or the DSA sythetics. "Sometimes" vertical stringing is caused by the steel hand guards heating up.

I have built 8 F A Ls and only had one that exibited vertical stringing. In my case, it was caused by excessive "slop" between the bolt carrier/bolt/ and carrier rails in the upper receiver. I was able to add metal to the inside of the bolt carrier and mill it down until everything fit snug. The vertical stringing disappeared after these mods were made.
Most often the vertical stringing is caused by the barrel heating up and warping. This is a result of poor metalurgy during manufacture or the barrel being produced in too big of a hurry.

If you are using the surplus StG 58 bipod, then either stop using it or accept the vertical stringing. Most folks think that the bi pod was added to increase the accuracy of the rifle. It wasn't. These rifles were designed to be used in semi and full auto fire. In full auto fire, the bipod is used to aid in controlling the rifle. When used in semi auto mode, it causes the barrel to flex and string the rounds vertically. (It does the same thing in full auto, but in full auto, it doesn't matter)

"Bipod"  Yep, roger that, I haven't used it either, and it's completely off now, so it has no chance of screwing up the harmonics. I hope this works, I want to keep this thing.
OMC

Actually...

You would WANT the extreme shot distribution in Full Auto Mode against the waves of godless Commie Heathen Invading Hordes!!  More Distribution means a larger "beaten area" of fire!

However for accurate marksman shooting, the bipod works against you!  (same as M-14!)

BIGGER_HAMMER