SUNRISE, Fla. — As Eddie Pereira helped his 15-year-old nephew fire a semiautomatic assault rifle for the first time, Mr. Pereira’s son, a more experienced shooter, snapped pictures of the rite with a phone.

Mr. Pereira, 45, is a regular at the target range here at Markham Park, a county-run recreation area outside Fort Lauderdale that offers family camping, boating, biking, a dog park, a nature trail and, at the far end, a 100-yard shooting range.

Arguments over gun control may boil in some quarters. But here, canoers, bird-watchers and even the dogs paid little heed to the distant crackle of gunfire. On the range itself, dozens of people practiced shooting with the very kind of rapid-fire, high-capacity weapons used in recent mass murders in California and Colorado and others before — the kind that President Obama and many others say should be banned.

Mr. Pereira, his brother and their two sons were trying out his new AR-15-style rifle, the country’s best-selling style of long gun, which looked as if it came straight out of a commando movie. He bought it for $600, then personalized it with $400 worth of accessories like different sights and grips. He has a 30-round magazine so he does not have to reload too often.