Some of the best selling Unertl scopes were the MST-150 10x for .50-caliber rifles and the MST-100 10x for 7.62 x 51mm rifles. These scopes achieved regarded status because they were used by the U.S. Marine Corps, the Federal Bureau of Investigation and Canadian forces.
The Unertl Optical Company produced target scopes from 8x to 24x from 1934 to 2008. In the 1950s and 1960s, these scopes were some of the best-known and lauded target scopes. The company also produced hunting scopes and spotting scopes, but it was best-known for the two scopes that the Marine Corps used. The Marine Corps used these two scopes until the early 2000s, when it began phasing them out for more technologically sophisticated scopes.
The 8x Unertl target scope used by the Marine sniper Carlos Hathcock in the Vietnam War was perhaps the most famous of any of the Unertl scopes because of Hathcock's notoriety as the sniper with the most confirmed kills in U.S. service history.
Unertl scopes have been said to decrease the value of some collectible firearms; installation of the unusually long scopes required the user to drill extra holes into certain firearms. The best way to obtain a Unertl scope as of 2015 is to find one installed in a classic firearm, checking to make sure no extra holes have been drilled in the rifle.