Why Does My Hat Instance All Over The Place?

I have a hat giver script that places a hat on a character when you touch a brick. It instances the part, and it works all fine, except for the fact that the position of the hat isn't consistent.

What I mean by this is that the hat wont always instance exactly where I want it to, it'll just instance a little to the right or a little to the left.

Here's the script:

01  h2.Name = "Vest"
02  p2.Parent = h2
03  p2.Position = torso
04  p2.Name = "Handle"
05  p2.formFactor = 0
06  p2.Size = Vector3.new(1, 1, 1)
07  p2.BottomSurface = 0
08  p2.TopSurface = 0
09  p2.Locked = true
10  game.Workspace.Hats.Ammovest:clone().Parent = p2
11  h2.Parent = hit.Parent
12  h2.AttachmentForward = Vector3.new (0, 0, 1)
13  h2.AttachmentPos = Vector3.new(0, -0.871, 0.768)
14  h2.AttachmentRight = Vector3.new (-1, 0, 0)
15  h2.AttachmentUp = Vector3.new (0, 1, 0)
16  p2.Position = p2.Position + Vector3.new(0.5,-3,0.82)