Why are the "John Wick" movies so great? A big reason is the collaboration between Keanu Reeves and director Chad Stahelski, who co-directed "John Wick" and worked solo on "John Wick: Chapter 2" and the upcoming "John Wick: Chapter 3 -- Parabellum."

Chad was a successful stuntman in the 90s and was Keanu's stunt double on "The Matrix." He continued with Reeves on the two more films, "Constantine" and "The Replacements;" worked with the Wachowskis on "V for Vendetta" and "Speed Racer;" and oversaw the first two "Hunger Games" movies. That list just scratches the surface of his credits.

This is relevant because Chad and Keanu have brought an expert crew's sensibility to making action pictures. They're building their action sequences into the script from the beginning, and it's not a situation where a director who doesn't know a thing about fights or weapons depends on experts to stage his movie and pits them against producers who are (always, by necessity) looking to shave some dollars off the budget.

The plots match up with a thousand other straight-to-video action pictures. It's the execution that elevates them into the creative, critical and box office successes they are.

That attention to detail extends to the weapons. Military.com met with some of the John Wick experts at SHOT Show 2019 and got some amazing details about how they've been allowed to practice their craft.

Taran Butler of Taran Tactical Innovations modified the Sig Sauer MPX rifle that's prominently featured in the new "John Wick: Chapter 3 -- Parabellum" trailer. Butler is a legendary competitive shooter who's made a career as a tactical weapons trainer on movies such as "Black Panther" and "13 Hours" and the TV series "S.W.A.T."

He talks about the custom work he did on the weapons and how seriously Reeves takes his tactical training. Butler is interviewed by Eli Crane, who's a Navy SEAL Team 3 veteran, chief executive officer of Bottle Breacher, and a Sig Sauer brand ambassador.

George Thompson from Benelli USA shows off a modified version of the company's Marine Corps-issue joint combat M4 shotgun. Butler handled the mods on this one as well, and Thompson gives the rundown on the changes below.

What the filmmakers are doing in "John Wick" seems obvious, but it's most definitely not easy. Check out "John Wick: Chapter 3 -- Parabellum" in theaters May 17 and watch the trailer below.

And check out this training video from "John Wick: Chapter 2" with Keanu Reeves and Taran Butler.