It is good practice to always 'gap' new rings. Push the rings into the barrell while its off the bike, and use the piston to square it in the bore at point near the top of the bore where there is least wear (this is the narrowest part of the bore so you need to take this measurement here). Now measure the gap between the ends of the ring with a feeler gauge. There is no definite measurement for this, but 0.1mm -0.12mm per inch of bore is a good rule of thumb (e.g a 54mm bore would need 0.2-0.25mm gap). If there is not enough gap then when the rings expand with heat they will touch, forcing the ring out and onto the barrell wall, increasing wear, and possibly ring breakage...you don't want this!. Use a V fine swiss file or whetstone to take material off the end of the ring to achieve the correct gap, and finish off the work with a final slight chamfer (because your removing material has created a sharp edge to the ring end which may dig into the barrell wall or chip off electroplating). Job done :-)