August 27, 2012: The U.S. Army is introducing a shorter and lighter version of its M110 SASS (Semi-Automatic Sniper System). SASS has been in use, first in Iraq and then Afghanistan, for four years. The CSASS (Compact Semi-Automatic Sniper System) will use a collapsible stock and a removable flash suppressor to get the length down to 91 cm (36 inches) long and the weight under 4.1 kg (9 pounds) unloaded. This will be done by modifying existing M110s (starting at 125 a month and increasing to 325). The CSASS is addressing demands from the troops for a more compact sniper rifle for the many snipers who are part of infantry units, not special sniper detachments.
The M110 has largely replaced the bolt-action M24 and provided commanders with much more effective snipers. That increase in numbers (of snipers) and their effectiveness has changed the look (less random fire from U.S. troops) and feel (the U.S. troops appear more in control) of the battlefield. It's also easier to spot the enemy. He's usually the guy firing on automatic. The fellows firing one shot at a time are the Americans and they are usually the last ones standing.
The M110 was not itself a big technological breakthrough. It is based on the older AR-10 rifle. The U.S. Navy had already been buying a similar weapon, the SR25 (also known as the Mk11) since the early 1990s.
All of these are 7.62mm semi-automatic sniper rifles based on basic designs developed by former marine Gene Stoner in the 1950s. This led to the M-16 and many other rifles. The basis for the M-16 was the AR-15, and a 7.62mm version of that weapon was called the AR-10. About half the parts in the SR25 are interchangeable with those in the M-16.
The M110 achieved its high accuracy partly by using a 20 inch heavy floating barrel. The "floating" means that the barrel is attached only to the main body of the rifle to reduce resonance (which throws off accuracy). The M110 weighs 7.9 kg (17.3 pounds) in combat and about 32 kg (70 pounds) with all components of the system. The M110 can use a ten or twenty round magazine. The 1.03 meter (40.5 inch) long rifle can have a 15 cm (six inch) tube attached to the barrel, which reduces the noise and flash made when the rifle fires and largely eliminates nearby dust rising into the air, which often gives away the sniper's position.
Previously, many snipers have had success using tuned up M-14s (from the 1960s) as sniper rifles. While semi-automatic and rugged, the M14 wasn't designed to be a sniper rifle. The AR-10 was a better model for a semi-automatic sniper rifle, since it is inherently more reliable and accurate.
As far back as World War II it was known that there were many situations where a semi-automatic sniper rifle would come in handy. But it's taken over half a century to solve the reliability and accuracy problems. The CSASS is also meant to satisfy users of the M-14s, whose size (118cm/46.5 inches, same as SASS) was always a drawback. The SASS, however, weighed a third more than the M-14. With the lighter and shorter CSASS, plus a reputation for accuracy and reliability, M-14 users should finally be lured away from their 1950s era sniper rifle.