this is the code i use , but it does just about nothing to terrain, as mutch as a ostriche sticking his head in the sand
and bouncing off stone surfaces.
could a misplaced centre of gravity be the problem ?
Edit.
last ditch effort would be to set it prettty high, just to test its working at all.
Edit.
shapness will not work so could someone explain deepgroups to me if that could help

Last I checked, sharpness doesn't do anything for MOSRotatings. If you want it to dig, mess with the deepcheck and deepgroup settings.

ive set deepcheck to 1 , helps a litte though im not familiar with deepgroup to really know what im doing there.

especially.

Resolution
Depth

Well, Deepgroups just eat the terrain. Any terrain. And they don't collide with actors. But, what i think might help a little would be to set the deepgroup depth equal to the atomgroup depth. Or, if that screws things up, add 1 to the deepgroup depth. This will only have a limited effect though, because mass and surface area (size of projectile) are the primary factors in how well an MOSRotating penetrates terrain.

So anyways, a bit more in-depth explanation of the two variables: Depth is how many pixels in from the outline that the group lies. This means that with a depth of 2, the group in question exists 2 pixels within the outline. Atomgroups are for collisions, and deepgroups are for terrain erasing. Resolution is a bit odd though, and i don't quite understand it myself, though here's how i think it works: With a resolution of X (a random number), only every X'th pixel is counted for the group. I think this mainly is for optimization, but a higher number in resolution might give you better terrain penetration, though the hole won't necessarily be very pretty.