Most bullets you can requisition during ship to ship combat will be light weight for low grav to no grav combat closer to the center of the ship, and other types of ammo are handed out depending on whether or not its needed. During ship to ship combat, we could indeed say that hollow points would be issued.
Since this isn't the far future, you can expect the shot gun, though with some enhancements, to still be the same brutal yet effective close range weapon its suppose to be. You can also expect the same depending on what bullets or shells you load your weapons with. Shotguns are shotguns, rifles are rifles. They just fire weaker bullets when onboard a vessel. Plenty enough power to punch through weak armour. Not enough to wreck starship material.
Inalucts idea seems right enough, but as for the walls and windows, let me give you the information.
The inner ship is made from a Titanium A and some variation of steel material, while the outside of the ship is a Ceramic mix, folded metal, and then plated armour to protect from heat, cold, mass, and speed. The main idea is that an attacker would have to break off each seperate plate of armour, but then penetrate hard hull.
And since it may be asked, The Retribution is a large, heavily armoured vessel, but it isn't a battleship, at least, not in its own arms. It has a few High Velocity Cannons, which can punch through armour and pretty much ignores all but plasma shields, and even then can break through them, but not enough for a large scale engagment on its own. It also maintains several torpedo batteries, has a small stockpile of nuclear weapons, and is also armed with a small craft defense system, though its computer controlled, and mostly spits out metal junk collected in space by drones.
The Retribution has no shields to speak of, and neither to any other ship besides perhaps alien vessels(This raises the question if there are various alien races! Haha! Now your all paranoid).
Sounds like an impressive armoury for ship-to-ship combat, yes? Against a single vessel? Yes. It can be a deadly opponent.
But the as a Expedition vessel, it has no chance against more then say, three opponents with out proper support. Which by the way is where fighter-bombers come in.
A proper flanking attack and we can be pinned down by one vessel, while two others attack our sides or behind until we fall apart. But we're not really meant to engage enemies, which is where the story may divert at somepoint.
Otherwise, our vessel is capable in that it has a small, but impressive array of weapons.
Has a large armoury, armed with new weapons.
Has a moderate sized force of Marines aboard.
And has several squadrons of Fighter-Bombers to engage other enemy vessels.
More on defense:
The hull of the starship can be seperated from the rest of the vessel and locked down until EVA suited engineers can fix the tear in the hull.
Every glass window is made of strong material, including the observation deck, which is pretty much on the bridge deck. Should any window break, it will be sealed almost instantly to prevent explosive decompression.
The Observation deck is sealed in a thick layer of Titanium A when the ship is in combat.
More later.