Quite possibly. I did not have my SLR at that time. Had to use P&S camera. Not much control.
But not sure whether I could achieve that using SLR too since I had to keep the camera lens just next to the opening because there was a glass covering the end. So with such a short distance from subject, might need to use macro. Then DOF will be narrow.
hmm...but just maybe if you lowered the exposure a little, the muzzle will be more defined =P
so since playing with the aperture will produced an undesired DoF, lower ISO?