When I weld a part that is bigger than the player to the players hand on an R15 rig the player bounces around I am guessing because its too big? The part is in its own model inside the player is there any way to fix this issue?

I used this script to weld the part to the player:

function Weld(Weldx, Weldy)
	local weld = Instance.new("Weld", Weldx) 
	weld.Part0 = Weldx
	weld.Part1 = Weldy
	weld.C1 = Weldy.CFrame:toObjectSpace(Weldx.CFrame)
	weld.Name = "Weld"
end
Weld(Part, RightHand)