Give it a rest, you are simply trying to jam this conversation to win the point by splitting the molecules holding a hair together. Motor canon are fixed to the center line of the motor, pulling G changes the IP point due to an increase in the force of gravity. None motor mounted nose cannons could be harmonized to an IP point and was never an issue with this post.
Give it a rest?
Seriously?
The purpose Bustr, of forum discussion is to derive useful information by the banter-like critical analysis of what other people say (me included) until you arrive at some useful information. You are stating it wrong when you say lateral G is influencing IP. The G force experienced by a rifle bullet going down the barrel is something around 100,000 G according to a brief Google search. Over what, a two foot barrel? So the lateral influence on internal ballistics exerted by the aircraft must be negligable to the point of hardly registering. Surely I need not prove the aircraft cannot influence the external ballistics of the shot? Pulling G does not change the IP - it changes the aiming point because you need to pull alpha to pull G. It's an aircraft issue not a gun issue.
Here are some pictures showing ground crewmen bore-sighting the cannon.
I think that fine-feathered gentleman might in fact be doing something else Devil. Note that the three-footed spider on the end of his device is touching the sides of the blast tube, not the barrel. The cannon mounts to the engine with a fixed 2 x 4-bolt mount.
You can see it here in Bustr's picture. Coplanar with the rear, blue frame ring:-
You can see the mounting position here on the back of the engine, just follow the airscrew centreline to the back:-
Here you can more clearly see the proportions of the blast tube:-
Tilting the cannon at the mounting point even slightly would very quickly violate the front hub's tube which is thinner than the one through the cam drive gear.
