Beginning in 1959, the ArmaLite company designed and developed the very first ArmaLite Rifles. Soon after, the company sold the rights to Colt, which continued to manufacture the rifle under the “AR” name, and redesigned the rifle by relocating its charging handle to the rear of the receiver, which was then marketed to, and adopted by, the U.S. Military as the fully-automatic M16 rifle.

Flush with the success of the rifle, Colt developed an alternate version that could be used by civilians, a semi-automatic near-replica they called the AR-15. While they closely resemble each other externally, the AR-15 and M16 differ greatly in their functionality. The hammer and trigger mechanisms are designed differently, and the bolt carrier and internal lower receiver of the semi-automatic versions are milled differently, so that the firing mechanisms are not interchangeable. Firing a semi-automatic firearm requires the owner to pull and release the trigger after each shot.

Despite manufacturing regulations – and in light of the 1986 passage of the Hughes Amendment to the Firearms Owners Protection Act that banned the manufacturing of fully-automatic firearms for the general public – there is now a conversion device on the market that allows the owner to shoot an AR-15 continuously until the trigger is released. It costs about $500, and it promises owners that it will turn a basic AR-15 into a nearly fully-automatic rifle. Civilians also have the freedom to customize their AR-15 with the use of barrels, stocks and optics.

Each rifle can be wrapped in several varieties of covers and colors, suitable to the owner.

Sales of the AR-15 semi-automatic rifle are soaring. The National Rifle Association has called the AR-15 the “most popular rifle in America,” proclaiming that “AR” really stands for “America's Rifle.” The organization estimates that 8 million are currently owned in the U.S., and it's been attached in its marketing campaigns to heroism, political resistance and enjoyment, and in some parts of the U.S., it is marketed to children for use at target shooting competitions.

On July 20, 2012, James Eagan Holmes entered the Century 16 movie theater in Aurora, Colo. During a midnight showing of the film, The Dark Knight Rises and, with multiple firearms including an AR-15 semi-automatic rifle, he shot into the audience and killed 12 people and injured 58 more.

On Dec. 14, 2012, 20-year-old Adam Lanza, using a Bushmaster XM-15 series semi-automatic rifle, fatally shot 20 children at the Sandy Hook Elementary School in Newtown, Conn.

On Dec.  2, 2015, Syed Rizwan Farook and Tashfeen Malik, using AR-15-style rifles, killed 14 people and seriously injured 22 others at the Inland Regional Center in San Bernardino, Calif.

On June 12, 2016, Omar Mateen, a 29-year-old security guard, killed 49 people and wounded 53 others in a terrorist attack inside Pulse, a gay nightclub in Orlando, Florida, United States. Orlando Police Department (OPD) officers shot and killed him after a three-hour standoff. He was armed with a semi-automatic rifle.

On Oct. 1, 2017, Stephen Paddock fired more than 1,100 rounds from semi-automatic rifles from his hotel room on the 32nd floor of the Mandalay Bay Hotel, in the direction of the Route 91 Harvest Musical Festival going on beneath him. He killed 58 people and left 851 injured.

On Nov. 5, 2017, 26-year-old Devin Patrick Kelley drove to the First Baptist Church in Sutherland Springs, Texas, wearing tactical gear, a ballistic vest, and a black mask that featured a white skull. Wielding a Ruger AR-556 semi-automatic rifle, he entered the church where a service had just begun, opened fire and killed 26 parishioners and injured 20 others.

On Feb. 14, 2018, using a semi-automatic weapon, 19-year-old Nikolas Cruz entered Marjory Stoneman Douglas High School in Parkland and opened fire, leaving 17 students and staff members dead and another 17 severely injured.

On Oct. 27, 2018, armed with an AR-15 semi-automatic rifle and three handguns, 46-year-old Robert Bowers, entered the Tree of Life Congregation Synagogue in the affluent Squirrel Hill neighborhood of Pittsburgh and opened fire, killing 11 people and injuring six others.

In the days that followed each of these shootings, hundreds of elected officials sent their thoughts and prayers to the families of the victims.

While there is no masking the fact that these murders are isolated incidents, they have become a forever burden on the manufacturing of a rifle that nearly all of its owners use responsibly and lawfully for marksmanship training and competition, or at shooting clubs.

And yet, these isolated incidents are increasing in number in the U.S. and together, they have formed a continual and now unbroken chain of violence that gives our talking head society license to point anywhere and everywhere for blame: a growing lack of civility; paper-thin gun legislation and an even weaker system of background checks; the selling of fear as a commodity; the meddling influence of the National Rifle Association on our elected officials; the need for increased funding for mental health services; and the endless rancor between pro-gun and anti-gun advocates.

While there are no easy solutions to this raging debate, there is no side-stepping the fact that the one constant in all of these mass shootings has been the presence of the AR-15 – America's Rifle. Something in this deadly equation that has caused these senseless murders must change, before that fateful day arrives when the members of the editorial department of this newspaper arrive at a crime scene in Chester County that becomes the next Aurora, the next Sandy Hook, the next Parkland, the next San Bernardino, the next Orlando, the next Las Vegas, the next Sutherland Springs, and the next Pittsburgh.

In light of these senseless deaths, can even the most hardened of gun owners, tethered to the fractious and interpretive wording of the Second Amendment, not be able to ascertain whether the continued protection of a semi-automatic rifle is worth more than a human life?