It's pretty simple to make, you could use something like this:
_barrel = _this select 0;
_explosion = "Sh_125_HE";
waitUntil {damage _barrel > 0};
_barrel setDamage 1;
_explosion createVehicle [(getPos _barrel select 0),(getPos _barrel select 2),(getPos _barrel select 3)];
Save that as a SQF script and execute it in the init lines of the barrels.