The new dlc unit for the Astra Militarum the Devil Dogs, they have Melta Cannons and the tooltip says they deal 6 Dmg (1 attack, 8 armor pen, 2 range, increased armor pen at half range).

If you fight against units single model vehicles with 6 or less armor (and no damage reduction) you deal your full 6 dmg, but anything past 7 armor will cut your dmg in half. For example:


-War Buggies (6 armor) you deal 6 dmg
-T7 Devilfish (7 armor) you deal 3 dmg
-Dreadnought (8 armor) you deal 3 dmg
-Leman Russ (9 armor) you deal 3 dmg at 1 range, and 2.7 at 2 range
-Bane Blade (10 armor) you deal 3 dmg at 1 range, and 2.5 at 2 range

Is this a game mechanic I'm not getting or a bug?

Nvm, I forgot blast could hit multiple units even if they are not infantry. All the 6 armor units I founded had multiple models (sentinles, warbuggies). Because of the 50% accuracy is doing flat 3 dmg