Hitbox offset not working

Help and Feedback Scripting Support
#1

Basically I am trying to offset the hitbox but the max offset I can get is somewhere around 5-6?
Heres the script :

function Combat:CreateHitbox(char, size, offset)
    local Hitbox = Instance.new("Part")
    Hitbox.Transparency = 1
    Hitbox.CanCollide = false
    Hitbox.Anchored = false
    Hitbox.Material = Enum.Material.ForceField
    Hitbox.BrickColor = BrickColor.new("Really red")
    Hitbox.Size = size
    Hitbox.CFrame = char.PrimaryPart.CFrame * CFrame.new(0,0,-offset)
    Hitbox.Name = "Hitbox"
    Hitbox.Parent = workspace.Debris

    Combat:Weld(Hitbox,char.PrimaryPart,1)
    return Hitbox
end