In preparation for the opening of his new film, “Shooter,” Mark Wahlberg took some time off to catch up with his college fan base. “Shooter” tells the story of a sniper (Wahlberg) wrongfully accused of an assassination attempt. With his career exploding, an Oscar nomination under his belt, and two young children, Wahlberg discusses his training with some serious weapons, his troubled childhood and the possibility of retirement.

What kind of weapons did you train with to prepare for this role?

Well, I had fired other weapons in other movies, obviously, but I had never done something as intense as sniper training. So we shot 50-caliber, which was the big weapon that we used. That’s the one that supposedly I assassinate the Archbishop of Ethiopia with. But that was the biggest of the weapons that was shot.

What was the biggest challenge in filming this new movie?

The physical and mental demands of the movie. You know, I knew going in it was going to be tough, but actually making the movie, the stuff was pretty rigorous.

How did you prepare for this role, and how different was it than your preparation for “The Departed”?

Well “The Departed,” I basically lived; my whole childhood was developing that character. And with this, I had no previous sniper training, so we went to sniper school, and physically I had to really transform before I was much heavier from “The Departed.” So I had to get into physical and mental shape.

Can you elaborate more on your childhood?

Well, you know, I grew up on the street and getting into a lot of trouble. I’d spent a lot of my childhood in and out of Boston Police Stations and dealing with cops and crooks and, you know, I just had a pretty tough upbringing.

But it was all things that I was able to use in playing that part. I really didn’t have to do much preparation. I was more familiar and comfortable with that world than anybody else involved, including Martin Scorsese. So I was glad that, you know, after causing my parents all that grief that I was able to put it to good use.

What’s your favorite character that you’ve played so far?

I’d have to say it’s between this character, Dirk Diggler [from “Boogie Nights”] and Sergeant Dignam from “The Departed.” But Dirk’s high up there. They’re all extremely talented and good at what they do.

You’ve said that you plan on retiring when you reach age 40, and you are 35 years old now. Why and how do you choose projects from here on out?

Well, I said it for two reasons. At the time, I was pretty frustrated with the kind of movies that I was being offered and the kind of movies that they were making. So we committed to only making the kind of movies that we would want to go and see, which has certainly revived my passion for filmmaking. I also have two small children and, you know, I’ve been focused on me for a long time and at some point, obviously, my attention is going to have to shift to them. But hopefully I’ll be in a position where I can still make a movie every year or two and be able to work from time to time.

You’ve done a lot of various roles recently. How do you choose which ones you’d like to do?

Basically, now we choose by which films we want to go and see in the theater, which roles we think people would want to see us in. You know, for a good portion of my career, it was all about the filmmaker, and we necessarily didn’t focus on the part or the script itself. And, you know, I think we’re at the stage of our career where we got to start satisfying the audience and ourselves.

How has your Oscar nomination affected these roles you choose?

Well, I certainly can’t just start looking for like English period dramas and stuff that’s going to get me nominated again. I got to just continue to make the kind of movies that I want to see and that people want to see me in and really not change much. But, you know, I’ve certainly gotten a lot of offers since the Oscar nomination. But you just to kind of do what we’ve always been doing.

Any last minute advice to college readers?

Well, you get out what you put in: hard work and determination and 110 percent commitment can take you wherever you want to go.

“Shooter” opens everywhere tomorrow.