[Argonians Rule]

I found this glitch (for halo1) to have three weapons

When you come out of the cutscene with Keyes, from the time you can move, you'll have a directive onscreen - '>>Get off the Pillar of Autumn'>>. That stays onscreen for roughly 5 seconds (from the time you can move after the cutscene). You have to round the corner of the bridge (pass the doorway out) BEFORE that directive fades from the screen in order to avoid triggering the checkpoint. If you succeed, your pistol won't load... so the game engine won't realize you have it. You can go pick up two other weapons... and then head back to the bridge. Somewhere between the doorway onto the bridge and Captain Keyes, you'll trigger a checkpoint - from here, head back out; you should have access to your pistol. (It won't show up automatically, but you can cycle through your weapons to get to it.)

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