Strange emonty. Wonder what the problem was. Maybe you poked through the center tube without knowing it. What I have been doing lately is to put a toothpick down in the carto to push the center tube away from the location I am about to drill. Kinda gives me a little back up insurance in case I poke too far. I was thinking about making a little tool to back up the inside of the tube to stop my poker from going too deep on accident. When its your last carto you surely don't want mess up...... Something to slide down between the filler material and the side wall of the carto might do the trick. I have a few 401 batteries that might get cut up because they are the next size tube down from the carto 901 etc. Slice it in half length ways and make it nice and smooth.
yes Keith. I was thinking the same, a pice of very strong metal or something to protect the tube from being pierced....still got enough carto's...lazy