My posting was only meant to attire the attention of the specialist in artillery matters and I believe the best one on this forum is Kevin.
The above mention is flemish - it means "honour to the one who deserves it"
Or in management terms (and I have a Master Degree in Management of public organisations since last year so I may make that comparaison) - the right person on the right place
On the other hand your answer is also good, although I would suggest that firing cannister with a howitzer will not have the same effect as firing cannister with a gun. All depends on the range you are aiming at. The effectiveness of a howitzer firing canister at 300 meters is practically nil in comparaison with a gun firing cannister at the same range, due to the ballistic qualities of both howitzers and guns - the shorter the tube, the wider the cannister will be spread of and the shorter the effectiveness will be.
You can compare it with a hunter shooting ducks with a rifle where the barrel has been sawn off.