diff --git a/src/mame/drivers/ssv.cpp b/src/mame/drivers/ssv.cpp
index 32a5847e324..6f2dee36d59 100644
--- a/src/mame/drivers/ssv.cpp
+++ b/src/mame/drivers/ssv.cpp
@@ -1335,13 +1335,13 @@ static INPUT_PORTS_START( gdfs )
 	PORT_DIPSETTING(      0x0000, "Heavy" )
 
 	PORT_START("GUNX1") // IN5 - $540000(0)
-	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(1)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(1) PORT_INVERT
 
 	PORT_START("GUNY1") // IN6 - $540000(1)
 	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_Y ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(1)
 
 	PORT_START("GUNX2") // IN7 - $540000(2)
-	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(2)
+	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_X ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(2) PORT_INVERT
 
 	PORT_START("GUNY2") // IN8 - $540000(3)
 	PORT_BIT( 0xff, 0x80, IPT_LIGHTGUN_Y ) PORT_SENSITIVITY(35) PORT_KEYDELTA(10) PORT_PLAYER(2)