All the rifle calibre FA shooting I remember doing was at 200m or longer range.
A BREN gun in good repair would keep 3-to-4 shot bursts in a 4" group at 200m, using the iron sights, of course, until the barrel got too hot to touch, then the groups grew a little, maybe 6" (that's one nice thing about the quich-change barrel).
The FN-C2A1 produced (for me) very linear groups from the prone position, the first shot going to POA, the next round impacting 10"-12" away at a 45° angle (I'm right handed, so the line extended up and to the right), the third round continued up and out another 10"-12". Any succeeding rounds just hit the berm. If I could use my C2 from a standing supported position (IE in a trench, the groups were much better owing to the ability to absorb the recoil in a better manner, at 200m, clusters in the 10"-14" were pretty much the norm.
The FN-C1A1 with a C2 trigger group was a lot of fun but at 200m it was all one could do to keep all of the shots on a 4" target, if shot from the standing-unsuppoted position, which was all we ever tried, because had we been caught, I've no doubt we'd have been in some trouble.
The belt fed M1919, in both original .30 cal and 7.62 NATO would sort of triangular groups with the base quite flat and about 6" wide and the group would be about 10" tall; but only about 2"-3" wide at the top. The sights are quite crude and of a very short radius, 30-40cm IIRC. This was with 5-8 round bursts, on the tripod. Firing from the hip with a sling over one's shoulder seemed quite accurate. it was easy to keep even quite long busts centred on quite small targets; but you also have to remeber that it was a 35 pound gun (IIRC).
The C1 SMG was capable of firing long bursts into 10" clusters at 25m. With short bursts (2-3 rounds) fried from the shoulder, using the sights, 4" groups were often obtained.
The only STEN gun I ever fired was a Mk2-S, with the suppressor. It was quite heavy, about 8 or 9lbs as I recall, and recoiled very little. It had a newish barrel. I shot some 4" groups at 50 yards with it, although the sights were crude the radius was reasonably long ( nearly 3 feet I think).
I got to try and UZI and although I didn't shoot any paper with it, my impression was that at 25m you'd be looking at groups in the range of 24".