Accuracy values for the main guns - MBT's.

[JaM]

I found those:
1000/1500/2000
105mm M68 with M735 98/87/74 (M60A3 in 1980)
105mm M68 with M111 95/81/67 (Merkava mk1 during Lebanon fighting)
120mm M256 with M827 98/84/70 (M1A1 during tests in 1985)
125mm 2A46 with APFSDS 87/66/46 (T-72 with laser rangefinder in 1980)
115mm 2A20 with BR5 86/60/43 (T-62 with laser RF 1980)

120mm M256 with M829A1 80% at 2500m stacionary,75% at 2000m moving

I posted some data from Slovak military buletin where T-72 had accuracy 57% at 2000m with 2A46 firing BM-15 round