Wow this got rather complicated quickly.
You don't need a frangible round to avoid puncturing a hull. Most firearms have subsonic rounds available. Also the amount of metal jacket on a round will effect it's ricochet ability.
For example, one plan out there for the use of Air Marshals, basically security guards on planes, calls for subsonic rounds with no metal jacket on the round. The combination of low speed and no jacket creates a round less likely to puncture the body of an airliner. If the bullet hits something hard at full force it has a better chance of splattering then ricocheting, this is dependnat on distance, material density, and a bunch of other technical bits to lengthy to list here. Since the lead is so soft the bullet will deform before it has a chance to bounce. The deformation will effect any bounce trajectory as well as the energy pushing the projectile.
Now the WC bit:
In the movie they used rail guns. The actual composition of the rounds is not known, though usually an aluminum spike is used. You also have nice thick metal walls. So the guns in WCM would create a lot of ricochets. However, movie gunfighting does not always take real world physics into account.
In the game series they would most likely use energy weapons for boarding operations because of the short burst time. The guns used in WC4 were most likely laser systems. The firing of a single laser bolt would not be enough to burn through a metal bulkhead. Once the bolt hits something the photons scatter and the heat will scorch the impact point, or leave a hole as well depending on what you're shooting at.
The problem here is that you have four elements adding to the tech of WC. You have the games, the books, WCA, and the movie. The games have never really done much for explaining weapons, whereas the books and movie have done quite a bit more. I haven't had a chance to watch WCA very much so I can't speak from experience on that. Since there is no true and final source of info on the weapons, except for WCM, then there will probably be no definitive answer to this question.
So my advice, make the smeg up!