imho, if the gun tips over on the table and is still pointing downrange, it's not a dq. OTOH, if the gun falls off the table, or ends up pointing uprange, then it would probably be a DQ.Tipping over is not the same as being dropped. Falling off of a table imho *is* the same as being dropped.
You need to read 10.5.3.1. I would argue that setting the gun so that it could tip over does not qualify as being placed "firmly and securely on " the object. A propped up gun that moves uncontrolled is a dropped gun.
I can see where certain types of people would argue that, but it certainly doesn't fit the definition of 'dropped' that is commonly understood in english. Using the same 'logic' you could say it was dropped if you set it down on it's side and it just moved a liittle. Imho, 10.5.3 pretty clearly backs me up, and suggests to an english-speaker that the gun would have to fall, not just tip over.
What happens if you knock your beer glass when reaching for your steak knife and the beer glass tips over wyile remaining on the table (and spills beer)? Do we say the glass 'fell'? No we say it tipped over. It didn't get dropped and it didn't fall. Otoh, if you knock the glass off of the table so it hits the floor, then you would say it 'fell' or was 'dropped'. The same linguistic nuances apply to a gun on a table.
Oops, I bumped the glass and caused it to fall over...