NEW ORLEANS - We now know many of the shots heard in video of Wednesday's attack were from a rifle.

Witnesses say James Hodgkinson began his attack near Eugene Simpson field in Alexandria near the left side of the fence. They say he carried a handgun and a rifle, and began firing with the higher powered weapon.

The FBI has released the bullet caliber used in the rifle was a 7.62 x 39 round. It's a high-velocity caliber; and it's designed to penetrate with accuracy.

"Congressman Scalise sustained a single rifle wound that entered in the area of the left hip it traveled directly towards the other hip, in what we call a trans pelvic gunshot wound," said Dr. Jack Sava, Dir. of Trauma Services at Med Star Washington Hospital Center.

Doctors say the bullet caused substantial damage to Rep. Scalise's bones and organs.

To better understand how a rifle caused so much damage, we traveled to Gretna Gun Works. It's reported the rifle was an SKS.

"These are military surplus rifles; they can also be called curio or relics depending on their age," Ryan Murphy, Gretna Gun Works Store Manager.

The SKS was a Soviet-designed rifle. It was notably the gun used by the Viet Cong against American troops during the Vietnam War.

"The average muzzle velocity of a muzzle of the 7.62 x 39 is typically around 2400 feet per second," Murphy said.

That's much faster than a hand gun and even faster than the speed of sound. On impact, it should take down large game.

"It can obviously be life threatening," Murphy said. "It depends on the hands of the shooter, the skill set and level of the shooter."

Witnesses say the attack went on for about 10 minutes before Capitol Police were able to take down James Hodgkinson.

And in light of how long it lasted, and the weapon used, it was remarkable more people weren't hurt.