>>Talking of which, what are those red things at the end of the barrel when on exercise? The British army use yellow ones. I presume they're to prevent the rifle from firing live ammo (but of course blanks can be fired) by some means, but I don't see how they work.
>
>No, they are blank adapters. Blank rounds are all powder, no projectile. The M16 is gas-operated, and without a projectile, the gas from a blank escapes too rapidly to load another round. The adapter restricts the escape of the gas enough to work the bolt.
>
>Firing a live round with a blank adapter on would be disastrous, which is why they are brightly colored (to remind the soldier that it's attached).

Thanks Daniel

That complements Tracy's explanation. I figured the bright colour was to remind the squaddy that it was there! :-)

Terry