Luke Bryan feels like a 30-year-old "mentally".

The country music singer turned 50 in July, but Luke doesn't think his age has really influenced his music.

Luke - who is releasing his new album, Signs, in September - told Billboard: "I don't know if I think about it. Mentally, I think I'm 30 anyway. I don't necessarily know if I think about stuff in that context.

"My biggest challenge as an artist that's been doing this for close to 20 years now is to try not to be overly redundant with your material, but then try not to stray away from what butters your biscuit.

"At the end of the day, I want a song to really touch me and, therefore, I think the odds are that it will do that to my fans.

"That's kind of the way I've approached every album. The bottom line is, I don't necessarily know if I approach it with a 50-year-old brain, I think I approach it with which songs are connecting with me the most, and which songs do I believe will connect with my fans the most."

Signs features a song called Killer, which is written from the perspective of a bullet in a gun.

However, Luke isn't trying to "start some pro-gun or non-pro-gun awareness campaign".

Speaking about the track, Luke explained: "It's really deep subject matter, a really dark song -- and really one of more well-written songs I've ever been a part of.

"These boys [Davis Corley, Mark Addison Chandler and Nate Kenyon] that wrote this song really wrote something very unique and special, and they went out there on a limb.

"Obviously, anytime you bring up guns -- certainly in music and movies and art -- it's a slippery slope, and [there are] so many different polarising opinions. This is just a story told from the perspective of a gun.

"I don't think it's my job to start some pro-gun or non-pro-gun awareness campaign, but when you hear a song like this, I just think the song is so great somebody needs to sing it, and I just said, 'I'm gonna be the guy that does it.'"