Movie shotgun question

[Slater]

I was watching the movie "Commando" on TV recently (you remember, the one where Arnie single-handedly wipes out a Third-World army). What's the shotgun that Arnold is using toward the end of the movie? Synthetic stock and extended mag; I didn't get a good look, but it appeared to be an extended mag Mossberg 500 with Ghost-Ring sights. Is this accurate?

Heck, that mag musta held 20 rounds :D

[Kevlarman]

Got a pic? I always thought it was an 870?

[Slater]

Could've easily been an 870. Didn't get a clear look at it.