The Colorado suspect used an AR-15-style pistol. Here’s what it looks like and how it differs from an AR-15-style rifle

Ahmad Al Aliwi Alissa purchased the weapon six days before the shootings in which 10 people were killed, according to his arrest warrant affidavit. The weapon had been modified with an arm brace, according to a law enforcement source.

The Ruger AR-556 is a type of AR-15, the military-style rifle that has been used in many other mass shootings. The pistol version is essentially the same weapon as the rifle but with a shorter 10.5 inch barrel and an adjustable stabilizing brace on the back — held against the shoulder — “to aid in accuracy, balance and recoil management,” according to the