What is the difference between an XM8 and a SM8?

Question

What is the difference between an XM8 and a SM8?

Answer 1

both the XM8 and the SM8 are very similar in design. the XM8 was designed to replace the legendary M-16 assault rifle but the idea was eventually scraped and so was the rifle. it was designed to be a multi-purpose weapon used as an assault rifle and soulc be adjusted to act as a sniper if needed. A famous variant of the M-16, The M4 carbine, is just a shortened version used for close quarter combat. so the M4 is to the M-16 as the MX8 is to the SM8, only differnce is has a slightly extended barrel that would be used soley for sniping

hope this helps