Leupold pretty much set the standard of what it is "tactically" correct with their MK6 scope. The MK6 1-6 and MK6 3-18 ( purchased by the socom) pretty much smack down the spec for tactical scopes of this category. Many manufacturers try to make something in the same vain, but none of them could get to the light weight achieved by Leupold.
Sig Sauer pretty much creates their own lower cost version of the MK6 with the Tango6. With the cheaper Leopold MK6 goes at over 2000 USD at street price, there is a large market where compromised can be made and keep the price between 1000 to 2000 USD. The Sig Tango6 scopes are packed with features. The 3-18X44mm comes with FFP reticle , Locking turret, cant indicator, illumination...etc, for the price difference, the Tango6 is 13 oz heavier than the MK6 and have about 10MOA less in adjustments.
3-18X44mm -34mm tube
The biggest competitor to the 1-6 is probably the vortex Razor HD Gen2. Without holding both scopes side by side I cannot offer much opinion, but the spec sheet shows that the Tango6 is about 5 oz lighter than the Razor HD Gen2. So if price is about the same, it will be a reason to go for the lighter one. In fact, Tango6 offers a horseshoe dot reticle that is similar to Trijicon's ACOG and VCOG, including 300blk reticle , this is a plus point for a scope in this category.
1-6X24mm-30mm tube
Sig Sauer pretty much creates their own lower cost version of the MK6 with the Tango6. With the cheaper Leopold MK6 goes at over 2000 USD at street price, there is a large market where compromised can be made and keep the price between 1000 to 2000 USD. The Sig Tango6 scopes are packed with features. The 3-18X44mm comes with FFP reticle , Locking turret, cant indicator, illumination...etc, for the price difference, the Tango6 is 13 oz heavier than the MK6 and have about 10MOA less in adjustments.
3-18X44mm -34mm tube

The biggest competitor to the 1-6 is probably the vortex Razor HD Gen2. Without holding both scopes side by side I cannot offer much opinion, but the spec sheet shows that the Tango6 is about 5 oz lighter than the Razor HD Gen2. So if price is about the same, it will be a reason to go for the lighter one. In fact, Tango6 offers a horseshoe dot reticle that is similar to Trijicon's ACOG and VCOG, including 300blk reticle , this is a plus point for a scope in this category.
1-6X24mm-30mm tube
