They don’t want you to reload them becuse most will split upon a 2nd firing becuse they are barely good enough for one.
I know a guy that bragged about reloading them for around 3 months, he realized non reloadable didn’t mean you couldn’t reload them, rather one shouldn’t reload them. Only cost him a Kart barrel to figure it out.
I found a bunch of Federal aluminum cases at the range one day. I always thought they were like the old Blaser, and berdan primed. Noticed these were boxer, and wondered just out of curiosity if they could be reloaded. So, as "test", I loaded up 50 and started shooting them to failure, just like I do my brass cases.
I treated them no different than my brass cases, and I had no troubles reloading them. I used the same load I use with my brass cases. Bullet tension seemed fine all along. They all shot fine. First reload (second actual loading), I lost a couple to split cases. A lot better than I was expecting. That seemed to be about the loss rate all along too, although the last couple of times, I was losing more, 3-5 an outing. I quit after 6 or 7 reloads, and still had over half of what I started with.
I had no damage to or problems with the Glock I was shooting them out of. The failures were all split necks, and they all occurred on firing, not while loading. The first couple of times out, I also checked to see if the bullets were setting back on chambering, and of the couple I checked, saw none.
Im not advocating doing this as a replacement for brass. I simply wanted to see if it was feasible. I think they more than passed that test. In a pinch, if they are all you had, they should work fine.