I never tried a full shotgun rush on the alien hive to win the game, and I probably never will because I want the game to last longer and be more fun... but anyway, I used a strategy several days ago that let the marines win.
What I did was build two spawns and an armory, then gave about 3 of my 5 marines shotguns. "Huh, shotguns?" "STOP WASTING OUR RES YOU IDIOT COM!" "WHAT ARE YOU DOING" "WE'RE SCREWED!!!"
Oh, but we were not screwed my young padawans. I convinced them to trust me, and they did. We went out, RT after RT, capping capping capping. Before long, it was 5 rts vs 5 rts. Then I got into base building mode, upgrading the armory, observatory, arms lab, proto lab, the works. I think one of the marines there never lost his shotgun. Anyway, after we prevented the aliens from getting multiple onos (one or two came, but quickly got owned. ^_^), I told all of my marines to take the phase back to main base... where I suited them with HMGs, GLs, Shotguns, and Heavy Armor. No one wanted a jetpack *sniffle*. Ah yes, and we secured a hive before the heavy armor already. Now that we had heavy armor, we moved on to the second hive, bang bang dead, build up a base with the hundreds of res we made... then off to the third, bang bang bang, build a siege to have some fun then rush in, boom, Team One Wins!
Now, this could easily be countered by the aliens, sadly, if several skulks decided to rush the IPs, which didn't happen that game, but to be on the safe side, next time I try a strategy like this and if I have enough marines, I will keep one shotgun marine defending the base. ^_^
And yes, I actually made this strategy up on my own before I learned of all of the shotgun rushing techniques, and completely forgot about how strong shotguns were.