I don't wear hearing protection when hunting, but always do when shooting from bench, etc. Noise above 85 decibels will eventually result in a hearing loss. Just guessing (since I don't have a chart), an 06 (with you behind the muzzle as opposed to even with or in front of) is probably in the neighborhood of 130-145. If you experienced any pain, you likely caused some damage in the cochlea. In some cases, your body will heal the damage. In others, or when you persist in exposing your hearing to repeated high decibel levels, some hearing is lost. Protect your hearing. When it's gone, it's gone!