Saithan; it is not hard to guess 300mm and 600+mm weapons would carry a lot of explosives.(really lots of explosives)
Generally with explosive amount those weapons carry have large effective pressure diameter.(if you are in that diameter, possibly you die) That makes them really destructive for human body in large areas. So, there is no need to say "anti-personel".
For example; 9K720 Iskander is a 920mm SRBM. Iskander-M is capable of carring 800 kg warhead. Lets say 600-700 kg of that warhead is explosive. That destroys any personel near to explosion, who is far away from explosion looks like that: