I have used 4 different crimping machines from cheap to ratchet crimping machines from different brands. I tried every possible way to get the fitting to curl, not stretch, and it was impossible. I've used red eyelets on 16 gauge wire and a red slot on my crimping tools and not once have I been able to get a crimp that won't pull out. I sat down on my bench and tried at least a dozen times. I've never tried shrinking them because that's the wrong way to make crimp connections. I even have a cheap wire cutter that cuts a hole in the heat shrink tubing and the connectors pull together almost effortlessly and should hold with a very strong pull. These suck. It is true.