Why don't criminals who get rid of guns rasp the inside barrel rifling? Have they already tried this?

The marks on a bullet from the riflings are called lands and grooves, as well as pin markings from the firing pin and other metal things that came in contact with the bullet. IT would be easier to just throw away the weapon after using it in a crime rather than try & mess up the riflings (what if you missed some part?). The riflings are there to give the bullet projectory and distance--so you would probably render any sort of aim useless. Look at this web for some great pictures & info on Lands & grooves: www.firearmsid.com/A_bulletIDrifling2.ht…