Punk rock is not what it used to be. Co-opted in the grand American tradition of cultural co-modification and repackaged for easy consumption by Warped Tour, iTunes and Hot Topic, the punk of today – sanitized by the blowtorch of commerce – is a fuzzy caricature of what it once was.

It is easy to forget how a quarter century ago the first generation of suburban children born of suburban children reacted to the social and political confines of Reagan's “Morning in America” like a magnesium strip to a match, creating music and a culture that forced together their collective anomie and fused it into something productive: American Hardcore.

The movie of the same name is an insider's take on this truly unprecedented and radical culture. Director Paul Rachman began chronicling the scene a week after seeing his first hardcore show as a college student in Boston during the early 1980s, he remembers “recording it because it was a way of being a part, we didn't know that 20 years later this was gonna be anything”

And now, more than two decades later, it is something, the foundation and touchstone for generations of people and bands with an aggressively independent mindset. Hardcore took a certain idea of punk rock and distilled it over and over again, creating songs that didn't need more than three chords and a minute-and-a-half to make their point and bow out. The movie makes the case for hardcore as an important counter-cultural movement according to Rachman, “It was a true subversive underground youth movement with a message”

And that message? Don't fuck with me, don't bother me, leave me alone, let me decide for myself. Hardcore was a lightning speed battle cry of affirmation to a generation of the disenfranchised. Rachman explains the basics of the ethic as “don't take any shit from anybody, do what you want, and do it all yourself. Those were very strong, bold ethics for 16-17-year-old kids to have.”

Although the music petered out in its original form by 1986, its ability to inspire continues to this day, from local scenes to major labels.

But what made this explosion possible? Rachman speaks of Hardcore with the same teeth-grinding intensity found in the music, saying, “It was a loud cry of frustration, and it wasn't coincidental that at the same time Ronald Reagan had just been elected president. There was this sweeping phony conservatism happening that we just didn't want any part of.”

The film traces the spread of hardcore, starting with its birth in the beachside dystopia of Southern California, then across the country to Washington, D.C., Boston and finally New York. It takes pains to show the regional differences of each scene, exposing fracture lines of class and ideology held together by an overall attempt to shield from the many indignities and rejections of teenage life in 1980s with slam dancing, anti-Reagan show fliers and self-glued 7-inch vinyl singles.

Hardcore is a culture predicated on an uncompromising sense of self-determination, so it is no surprise that filming the movie was an independent venture for Rachman and writer Steven Blush. When asked if the film could have been done through a studio, Rachman doesn't hesitate to respond, “Absolutely not, not this film. Some company could have made a film about hardcore but they're not gonna get the real story. These interviews were not interviews with questions; they were conversations. They knew who we were.”

Using their personal connections, Rachman and Blush assembled an impressive cross section of personalities from the original scene, getting interviews with scene patriarchs from Black Flag, Minor Threat and Bad Brains, to smaller players on the scene like Flipper and SSD. Fittingly, the film is a product of the very ethic it depicts: DIY.

“It was one camera, one mic, Steven Blush and I out on the road,” says Rachman. Just as good as the interviews is the live footage, showing bands flailing and shredding in veteran's halls and boarded up buildings, exhibiting the sort of testosterone-heavy violence that would eventually lead the scene to burn itself out.

Rachman sees hardcore as a forgotten era in American music and culture, yet one that whose influences were vital, “You look at these big rock documentaries they kinda skip from the end of '70s rock or new wave, and go right to Nirvana.” There wouldn't even have been any successful ‘grunge' or ‘alternative' groups if it wasn't for the missing link influence of hardcore.

The film tells its story without any sugar coating, taking a bunch of men in their 40s and allowing them to look back on the mess they made, sometimes proudly, sometimes with melancholic nostalgia. Rachman looks back and almost allows a laugh, “This was something that was so ahead of its time in a way, that nobody was paying attention.”

With American Hardcore , maybe more people finally will.

American Hardcore releases in theaters Sept. 29.