Blast Rod
This mod adds a single block, the Blast Rod, that breaks every movable block is pushed into.
It can only break blocks that a piston can move, and only if the direction it is pushed is the same as it is facing, i.e. the opposite of where the iron part is.
Recipe
You can place the ingredients in any column of the 3x3 Crafting Table grid.
Compatibily
I haven't met any incompatibility issue with the test I've done. However, to implement this, I had to reimplement the algorithm that calculates the blocks pushed or pulled by a piston. So any other mod that interacts with the vanilla algorithm may not work properly. Let me know here if you find any issue, and I'll see what I can do.