During the production of Starship Troopers, the actors used a variety of different weapons as a part of their role as 'Cap Troopers'.  The most prominent weapon carried was the Morita Rifle (see Weapons).

The actual rifles came in three versions -

Fiberglass shells containing actual firearms (called 'Live fire' props)

Fiberglass shells with replica resin cast firearms

Rubber full-scale casts

The basic rule was the fiberglass versions were used for close-to-camera work, and the rubber versions were used by background talent further out of shot, and for stunt purposes (where a fiberglass version may be damaged).

Here are a few occasions in the movie where you can spot the different types being used by the actors!

These are a few simple ways to spot a stunt rubber Morita gun from a fiberglass one.

On the fiberglass Morita rifles the ventilation vents along the barrel and above the triggers are drilled and cleaned to allow ventilation and cooling for the firearms.  You can see this marked in blue on the diagram.  On the rubber Morita rifles these ventilation holes are solid rubber and cannot be 'seen through'.  Also, the triggers are black and slightly reflective to light on the fiberglass versions.  This is indicated in red on the diagram.

Here you can see the fiberglass triggers from the front (marked in blue).  In addition, you can see the resin mini-14 in the ejection opening at the rear of the shell.  It is a resin cast of the actual firearm and is extremely highly detailed (marked in red).  The rubber Morita version has this replica firearm sculpted into the rubber finish and is VERY low detail in comparison.

Here you can see again in close detail the ventilation openings in the fiberglass Morita barrel.  The openings are completely open and you can see through them (and also see the inserted silver firearm barrel).

Finally, here is the tip of the fiberglass Morita.  It is fitted with an actual metal 60-cal Flash supressor.  This is held in place by a black metal "A" clamp which fixes it firmly to the lower shotgun barrel.

Here is the rubber Morita version.  You can clearly see the flash supressor is solid rubber and is simply moulded into the body.

Here you can see the rubber Morita tip again (marked in red), and you can also see the ventilation holes (marked in blue).  You can clearly see that the openings are NOT drilled and that the entire piece is solid rubber.

Here is the rear of the rubber Morita version, and the ejection opening.  You can see clearly that on the rubber version, the replica firearm is simply a low-detail extention of the rubber body (marked in red), rather than a 3-dimentional cast as seen with the fiberglass Morita.  You can also see that the triggers are not black as with the fiberglass Morita: they are simply moulded into the body and left the same olive green as the rest of the body.

Those are just a few simply pointers on how to spot and distinguish the rubber stunt Morita rifles from the fiberglass versions!

Rico makes his Flip-6-3-hole jump in the lazertag game. He is carrying a rubber morita fitted with a fiberglass Morita Lazertag tip.

You can see the rubber mould seam along the top of the Morita as Rico makes the Flip-6-3-hole jump.

Dizzy takes aim on the bugs with her rubber Morita on Tango Urilla.

I'm sure the bugs wouldn't be too afraid of a rifle with solid rubber barrels!

Another shot of Dizzy with her rubber Morita.

Rico jumps clear after firing the tactical nuke...

...and lands safely in the trench...

Lucky he was using a rubber rifle and not one of the Live Fire ones - I don't think a fiberglass rifle could take that kind of impact!  Be more careful Trooper!

Dizzy takes cover from the nuke blast in the trench - she still has her rubber Morita from the previous scene.

Rico, Carmen and Ace run from the iminant nuke blast in the bug tunnels.  Here you can see Ace has replaced his fiberglass Morita for a safer rubber one, and Rico also appears to have a rubber Carbine.