Thanks for the help mate i had the attachment.uc file but i had no idea that i had to refer it in the rifle's code.. that was class! everything is fine now

Here's the mutator's code

[code:1:d39c8059ca]class zOmMutator extends UTMutator; 

function InitMutator&#40;string Options, out string ErrorMessage&#41;
&#123;
	if &#40; UTGame&#40;WorldInfo.Game&#41; != None &#41;
	&#123;
		UTGame&#40;WorldInfo.Game&#41;.DefaultInventory&#91;0&#93; = class'zOmMutator.UTWeap_zOmRifle';
		UTGame&#40;WorldInfo.Game&#41;.DefaultInventory&#91;1&#93; = class'zOmMutator.UTWeap_zOmXloc';
        &#125;
Super.InitMutator&#40;Options, ErrorMessage&#41;;
&#125;

function bool CheckReplacement&#40;Actor Other&#41;
&#123;
	local UTWeaponPickupFactory WeaponPickup;
	local UTWeaponLocker Locker;
	local UTAmmoPickupFactory AmmoPickup;
	local class&lt;UTAmmoPickupFactory&gt; NewAmmoClass;

	WeaponPickup = UTWeaponPickupFactory&#40;Other&#41;;

	if&#40;WeaponPickup != None &amp;&amp; !Other.IsA&#40;'UTVehicleWeapon'&#41;&#41;
	&#123;
		if&#40;WeaponPickup.WeaponPickupClass != None&#41;
		&#123;
			WeaponPickup.WeaponPickupClass = class&lt;UTWeapon&gt;&#40;DynamicLoadObject&#40;&quot;zOmMutator.UTWeap_zOmRifle&quot;, class'Class'&#41;&#41;;
			WeaponPickup.InitializePickup&#40;&#41;;
			return true;
		&#125;
	&#125;
	else
	&#123;
		Locker = UTWeaponLocker&#40;Other&#41;;

		if &#40;Locker != None&#41;
		&#123;
			ReplaceWith&#40;Locker, &quot;zOmMutator.UTWeap_zOmRifle&quot;&#41;;
			return false;
		&#125;
		else
		&#123;
			AmmoPickup = UTAmmoPickupFactory&#40;Other&#41;;

			if &#40;AmmoPickup != None&#41;
			&#123;
				NewAmmoClass = class&lt;UTAmmoPickupFactory&gt;&#40;DynamicLoadObject&#40;&quot;zOmMutator.UTAmmo_zOmRifle&quot;, class'Class'&#41;&#41;;
				AmmoPickup.TransformAmmoType&#40;NewAmmoClass&#41;;
				AmmoPickup.AmmoAmount = 20;
				return true;
			&#125;
				
		&#125;
					
	&#125;

	return true;
&#125;

DefaultProperties
&#123;
	GroupNames&#91;0&#93;=&quot;WEAPONMOD&quot;
        GroupNames&#91;1&#93;=&quot;WEAPONRESPAWN&quot;
	GroupNames&#91;2&#93;=&quot;HANDICAP&quot;
	GroupNames&#91;3&#93;=&quot;POWERUPS&quot;&quot;
&#125; 
[/code:1:d39c8059ca]

Really appreciated mate :)