The original article was at SIG SG 550. The list of authors can be seen in the page history.
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The SIG SG 550 is an assault rifle manufactured by Swiss Arms AG that chambers the 5.56x45mm NATO round.
The SIG SG 550 is a weapon that was supposed to be featured in both Tom Clancy's Rainbow Six: Vegas and Tom Clancy's Rainbow Six: Vegas 2, but was later cut from the final product. This weapon was found among the files of the PC versions of both games. There seems to be a Rifle Scope on it, so the weapon is presumed to be the SIG SG 550 Sniper.