I hacked a 302 and it was attacking a 249 (moving towards it). The 249 fired at
it, but the 302 wasn't slowed down by the 249s bullets. Usually bots are slowed
down if they are being hit.

r4897

This is because the 249 bot does 1 damage (see map/item_archtypes.dat).

According to lines 997-1006 of src/enemy.c, only hits that do greater than 5% of
the max target health have a chance to stun. So a 302 (with max hp of 30) cannot
be stunned by this. Bots like the 296 Sawmill (max hp 300) will rarely be stunned.

A 249 bot therefore can only stun bots with a max hp of less than 20.