A OpenShotgun2

A_OpenShotgun2 is a code pointer used in the attack animation for the Super Shotgun.

just plays the sound effect DSDBOPN. The sound source is the player that triggered the function.

Uses
The  code pointer appears in the following states in Doom's state table:

Example
The following is an example of how to set the  code pointer in a Dehacked file:

Pointer 21 (Frame 34) Codep Frame = 39

Or using BEX syntax:

[CODEPTR] Frame 1234 = OpenShotgun2