Why do objects stutter when my character throws them?

Ok, so my place has flashbangs, and when you press G, the animation plays. When the animation is done, the weld that attached the grenade to the arm is destroyed, and the grenade is thrown. But for some reason, after 1/10th of a second, the flashbang sort of stops in mid air then resumes flying a split second later. I have no idea why it's doing this, I tried disabling the scripts to isolate the problem, and I figured out it happens 1/10th of a second after the Weld is destroyed. Any suggestions as to how I would go about fixing this?

EDIT: Added Code

function ThrowGrenade(Grenade)
	_G.MainGui.CrossHair1.Visible = false
	_G.MainGui.CrossHair3.Visible = true
	Humanoid.WalkSpeed = 16
	local Grenade = Grenade:Clone()
	Grenade.Parent = game.Workspace
	for _,v in pairs(Grenade:GetChildren()) do
		if v:IsA("BasePart") and v ~= Grenade:WaitForChild("Center") then
			local Weld = Instance.new("Weld")
			Weld.Part0 = Grenade:WaitForChild("Center")
			Weld.Part1 = v
			Weld.C0 = Grenade.Center.CFrame:toObjectSpace(v.CFrame)
			Weld.Parent = v
			v.Anchored = false
		end
	end
	Grenade:WaitForChild("Center").Anchored = false
	local Weld = Instance.new("Weld")
	Weld.Part0 = FakeRArm
	Weld.Part1 = Grenade:WaitForChild("Center")
	Weld.C0 = _G.GripC0
	Weld.Parent = FakeRArm
	_G.TweenJoint(_G.LWeld2,CF(),CFANG(0,RAD(80),0),_G.Linear,0.25)
	_G.TweenJoint(_G.RWeld2,CF(),CFANG(0,RAD(-80),0),_G.Linear,0.25)
	_G.TweenJoint(_G.LWeld,_G.ArmC0[1],CF(-0.2,0.8,0.1) * CFANG(0,0,RAD(-30)),_G.Linear,0.25)
	_G.TweenJoint(_G.RWeld,_G.ArmC0[2],CF(0.2,0.8,0.1) * CFANG(0,0,RAD(30)),_G.Linear,0.25)
	wait(0.3)
	
	local Ring = Grenade:WaitForChild("Ring"):Clone()
	Ring.Parent = _G.TextureFolder
	Ring:BreakJoints()
	
	local RingWeld = Instance.new("Weld")
	RingWeld.Part0 = _G.FakeLArm
	RingWeld.Part1 = Ring
	RingWeld.C0 = _G.FakeLArm.CFrame:toObjectSpace(Ring.CFrame)
	RingWeld.Parent = _G.FakeLArm
	Grenade:WaitForChild("Ring").Transparency = 1
	
	_G.TweenJoint(_G.LWeld2,CF(),CFANG(0,RAD(45),0),_G.Sine,0.2)
	_G.TweenJoint(_G.RWeld2,CF(),CFANG(0,RAD(-45),0),_G.Sine,0.2)
	_G.TweenJoint(_G.LWeld,_G.ArmC0[1],CF(0,0.8,0.1),_G.Sine,0.2)
	_G.TweenJoint(_G.RWeld,_G.ArmC0[2],CF(0,0.8,0.1),_G.Sine,0.2)
	wait(0.2)
	
	Ring:Destroy()
	_G.TweenJoint(_G.LWeld2,CF(),CF(),_G.Sine,0.3)
	_G.TweenJoint(_G.RWeld2,CF(),CF(),_G.Sine,0.3)
	_G.TweenJoint(_G.LWeld,_G.ArmC0[1],CF(0,0.5,0.1) * CFANG(RAD(90),0,0),_G.Sine,0.3)
	_G.TweenJoint(_G.RWeld,_G.ArmC0[2],CF(0,0.4,0.1) * CFANG(RAD(-80),0,0),_G.Sine,0.3)
	wait(0.3)
	
	repeat wait() until (not _G.Keys["g"])
	
	_G.TweenJoint(_G.RWeld,_G.ArmC0[2],CF(0,0.8,0.1) * CFANG(RAD(-10),0,0),_G.Sine,0.1)
	wait(0.07)
	
	Weld:Destroy() --This is the weld that holds the grenade to the arm
	Grenade.Center.Velocity = Grenade.Center.Velocity + ((_G.HeadBase.CFrame * CFANG(RAD(10),0,0)).lookVector * 150)
	Grenade.Center.CanCollide = true
	Grenade.Main.Player.Value = Player
	Grenade.Main.Parent = Grenade
	Grenade.Main.Disabled = false
	
	wait(0.4)
	
	_G.SwapAnim(0.2)
	_G.MainGui.CrossHair3.Visible = false
end