Herbie--When you try to put a piston with the ring on it into the cylinder, you should use lots of 30 or 40 weight lubricating oil on the cylinder and on the ring and piston. If it is possible to insert the piston from the bottom of the cylinder, then you should machine a slight tapered lead in at the bottom of the cylinder and polish the entry to break any sharp edges with some 200 grit carborundum paper while the cylinder is still in the lathe. If you have to insert the piston from the top of the cylinder, where a tapered lead is not acceptable, then at least break the sharp edge at the top of the cylinder bore with a bit of 200 grit carborundum paper. you can't just push the piston straight in, or you get the results you have already seen----shearing the outer diameter off of the ring and ruining it. It is a bit of an art.---I always make it a point to have the connecting rod attached to the wrist pin in the piston to use as a "handle". Insert the piston from the bottom of the cylinder, and "wiggle" it a bit as you try to get the ringed area into the cylinder bore. ---Brian