PC Auto Mag Light Gun - Lag after off-screen reload

[egregiousguy]

Not sure if there's a specific light gun sub therefore I'm posting this question here and hopefully someone has come across this issue before with a possible solution.

I've recently acquired a PC Auto Mag, yes this is the one with a VGA Box, ps/2 KB and mouse inputs and a passthrough VGA cable, and got everything squared up.  It works so much better than the Guncon2/Wingun setup, sans tracking though.  Calibration is spot on and off-screen reload works perfect but there's one catch.  Whenever I shoot the screen after an off-screen reload there's a bit of lag before the shot registers.  After days of trying to figure it out I finally figured out that the cursor always wants to jump to 0,0 from where the cursor currently is then to the trigger point.  I tried writing an ahk script with "MouseGetPos" and "MouseMove" or "Click, right" to save and recall the last onscreen shot and go back to it whenever the "right click" was triggered.  While this worked perfectly with the mouse, it didn't with the gun; the next onscreen shot would still jump from where the cursor currently is, then to 0,0 and then finally to the point creating the lag between trigger and input.  But after that one shot lag the gun works flawlessly until the next off-screen reload. Been trying to play some House of the Dead on M2 but the lag is killing the game play.

Anyone have any thoughts on how I'd be able to fix this via software or hardware?
Thanks in advance.