So, I use this
One day I'll buy an APP they look awesome but I am poor. Like you I drastically needed something than my standard deburring tool in a drill, honestly it fuckin sucked it got incredibly dull after a few cases and by the time it made an adequate cut to remove the crimp the case would heat to 1000 degrees and my hand would cramp. Try the above if that sounds at all familiar to you and you don't wanna spend the money on an APP (However if you can, do it, I've only heard really good things about it).
It looks like the same thing as a deburring tool but doesn't suck ass and dull.
Hey OP, chuck this in your power drill.
It's literally almost the exact same thing as a deburring tool, however it's made with much better metal than any of the deburr/chamfer stuff I've ever bought from proprietary reloading companies. The shit straight CHEWS through crimps like nothing. I mean like you run the drill, touch the casing lightly to the bit for ~ 1 second and you're done. I saw that you mentioned needing a glove to grip the cases as well using your deburring bit, and that reminded me all too well of what you are going through. When I would decrimp w/o the countersink (using the deburring bit), I would have to grip the casing uncomfortably firm with my hand, typically have to press it REALLY hard against the bench, and slowly grind out the crimp as the casing heats up to 700 degrees Celsius because the bit just seemed to dull after like 5 casings and would cause crazy friction. You might not think the countersink bit will be that different, but this ten dollar part has literally changed the game for me. I decrimped the last 100 cases of 5.56 I was reloading in about 8 minutes with the countersink Saturday. With the deburring too it would take me over half an hour at least, and my hand would be cramped, burned, and a bit raw lol.
One day I will spend the money on a swager, but I am likely going to use the countersink for a long while due to how easy it is (and that it was $10, and a good swager is much more than $10)
Hope you try this out man and I hope it helps. Decrimping my brass was one step that genuinely took a lot of the fun outta reloading for me, now it's just as easy to me as any other step and it's all because of a ten dollar part lmao.