Proton Cannon set-up problem

For those familiar wit Iron Man’s/War Machine’s combo crouching LP, MP, Repulsor Blast (LP) I can cancel the last hit Of Iron Man’s into Proton Cannon but I can’t with War Machine ? what the hell! But I can set it up into War Destroyer.

this is what i use

inf till you get to the corner right when your gonna land the up/fp S.hk to hk super which works and does super stupid damage…

hope this helps

scrubkiller 4 life…