How to add damage radius where a bullet impacts

Just like the title says, I need a simple line to create a damage radius where a bullet impacts

Part of the code if anyone needs it



function SWEP:PrimaryAttack()

game.AddParticles( "particles/hunter_projectile.pcf" )
PrecacheParticleSystem( "hunter_projectile_explosion_1" )

if ( !self:CanPrimaryAttack() ) then return end
 
local bullet = {} 
bullet.Num = self.Primary.NumberofShots 
bullet.Src = self.Owner:GetShootPos() 
bullet.Dir = self.Owner:GetAimVector() 
bullet.Spread = Vector( self.Primary.Spread * 0.1 , self.Primary.Spread * 0.1, 0)
bullet.Tracer = 1
bullet.TracerName = "AirboatGunHeavyTracer"
bullet.Force = 0 
bullet.Damage = 10000
bullet.AmmoType = self.Primary.Ammo 
bullet.Callback = function( attacker, tr, dmginfo )

dmginfo:SetDamageType( bit.bor( DMG_AIRBOAT,DMG_BLAST,DMG_DISSOLVE,DMG_SHOCK,DMG_BURN,DMG_PLASMA,DMG_DIRECT,DMG_GENERIC ) );

end
 
local rnda = self.Primary.Recoil * -1 
local rndb = self.Primary.Recoil * math.random(-1, 1) 

self:ShootEffects()

self.Owner:FireBullets( bullet )
	local tr = self.Owner:GetEyeTrace()
		local Pos1 = tr.HitPos + tr.HitNormal
		local Pos2 = tr.HitPos - tr.HitNormal
	util.Decal("FadingScorch", Pos1, Pos2)

	 if SERVER then
        local hitposent = ents.Create("info_target")
        local trace = self.Owner:GetEyeTrace()
        local hitpos = trace.HitPos
	local explosioneffect = ents.Create("env_explosion")
        explosioneffect:SetOwner(self:GetOwner())
	explosioneffect:SetPos(hitpos)
	explosioneffect:Spawn()
	explosioneffect:Fire( "explode", "255", 255 )
        end