	<weapon type="M4">
		<data slot="RIFLE" firetype="INSTANT_HIT" damagetype="BULLET" group="RIFLE_ASSAULT" targetrange="100.0" weaponrange="165.0" clipsize="100" ammomax="300" timebetweenshots="88">
			<damage base="30" networkplayermod="2.5" networkpedmod="1.25"/>
			<physics force="42.0"/>
			<reload time="2066" fasttime="1166" crouchtime="2066"/>

			<aiming accuracy="0.55">
				<offset x="0.14" y="1.0" z="0.55"/>
				<crouchedoffset x="0.08" y="1.0" z="0.12"/>
				<reticule standing="0.6" ducked="0.5" scale="0.3"/>
			</aiming>

			<pickup regentime="600000" ammoonstreet="15"/>

			<controller>
				<rumble duration="90" intensity="0.1"/>
			</controller>

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

		<assets model="w_m4">
			<anim group="gun@ak47">
				<rates firerate="2.0" blindfirerate="2.0"/>
			</anim>
			<effects>
				<muzzle fx="muz_machine"/>
				<shell fx="weap_ejected_rifle"/>
			</effects>
		</assets>
	</weapon>

Credit goes to GTAIV_Dark_Vade for weapon script line, modified by Naruto 607.
You must first have the MG36 mod from Push first before using this line (I recommend it for 4 weapon versions).
This is supported for Carbine Rifle Fallout NV Configurations, just copy the required lines only.

Link: http://www.gta4-mods.com/weapons/push-hk-mg36-plus-sight-options-f14092