Ensure that you are using the original default.ide for the mod to work.

First, import new gun@baretta.wad to pc\anim.img with SparkIV or OpenIV.

Second, with SparkIV, export your WEAPONS.ivaud from resident.rpf (find it in
pc\audio\Sfx). Open the WEAPONS.ivaud with GTA IV-aud and import all sound files
to here (match the names):

PUMPACTION_SHOT_L
PUMPACTION_SHOT_R

Save once done and import back to resident.rpf, Save and close.

Now install the new WeaponInfo to Baretta line below:

	<weapon type="BARETTA">
		<data slot="SHOTGUN" firetype="INSTANT_HIT" damagetype="BULLET" group="SHOTGUN" targetrange="30.0" weaponrange="188.0" clipsize="12" ammomax="96" timebetweenshots="433">
			<damage base="100" networkplayermod="5.0" networkpedmod="1.0"/>
			<physics force="150.0"/>
			<reload time="2933" fasttime="2933" crouchtime="2933"/>

			<aiming accuracy="0.05" pellets="32">
				<offset         x="0.15" y="1.0" z="0.55"/>
				<crouchedoffset x="0.15" y="1.0" z="0.05"/>
				<reticule standing="1.0" ducked="1.0" scale="0.0"/>
			</aiming>

			<pickup regentime="480000" ammoonstreet="15"/>

			<controller>
				<rumble duration="200" intensity="1.0"/>
			</controller>

			<flags>
				<flag>GUN</flag>
				<flag>CAN_AIM</flag>
				<flag>CAN_FREE_AIM</flag>
				<flag>ANIM_RELOAD</flag>
				<flag>ANIM_CROUCH_FIRE</flag>
				<flag>2HANDED</flag>
				<flag>HIGHER_BREAK_FORCE</flag>
				<flag>ARMOUR_PENETRATING</flag>
			</flags>
		</data>

		<assets model="w_pumpshot">
			<anim group="gun@baretta"/>

			<effects>
				<muzzle fx="muz_shotgun"/>
				<shell fx="weap_ejected_shotgun"/>
			</effects>
		</assets>
	</weapon>