In their objection to Christians who wear a cross, Mormons ask, "if Jesus had been killed by a gun, would you wear that around your neck?" The question exposes the Mormon's depth of depravity and disrespect for the Holy scriptures, as they reduce the cross's significance to that of a mere murder weapon. If I were inclined to wear anything around my neck, and a gun had been used to kill the Savior, then yes, I would wear a gun around my neck. Because, that gun would not be, any more than the cross was, the murder weapon that killed my Savior. 

The cross represents the power of God unto my salvation. 1 Corinthians 1:18 For the story and message of the cross is sheer absurdity and folly to those who are perishing and on their way to perdition, but to us who are being saved it is the [manifestation of] the power of God. (Amplified Version)

Fact is, the cross did not kill the Savior, nor did the nails in his hands and feet, nor did the soldier's spear in His side, nor did the beating and whipping beforehand, nor did the subsequent carrying of His cross through the streets leading to the hill called Golgotha. What killed the Savior was God's love for me that He sent the Savior as my replacement; which place the Savior took willingly to pay the penalty of death, which I deserve.

Romans 6:23 For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.

My sins killed Jesus. The Savior was God's (thoroughly undeserved) gift (grace) of eternal life to me. He saved me from the well-deserved certainty of eternal damnation in the lake of fire. The Mormon's question proves that Mormon's entirely miss the point of the Savior's cross, despite and given the Apostle Paul's proper, and inspired representation of it.