The weapons are part of the item sets that are still very much work in progress, as with any kind of "new" thing in KSP whether it be a weapon or a boat part for example there are many problems that can arise, such as error spamming which causes game crashes and game breaking (ie. the weapons are part of a set/group of parts that is no where near release. They are still very experimental). Also can you give us any more details as to "how" our mk4 carrier broke your game? ie. computer specks possibly a error readout (alt+F2) without anything to go on we really cant help you.