I currently have the AA battery core for my MIAD grip, but I will be switching to an ACS stock soon so I can store the batteries in the stock and won't need to keep them in the grip. I was thinking I'd switch back to the original 3 round core, remove the rubber insert and store a small bottle of gun oil in the grip instead. I planned to try to find a small bottle (like an eye drop bottle) and clean it out and fill it with oil. Then, close the bottle in a zip-loc bag in case of a leak. So, my questions are... 1. If you are doing this, what size bottle are you using and where did you find it? 2. Have you ever had an issue with leaks? 3. Have you ever had an issue with heat causing a problem like melting the ziploc bag?