The NT stands for Non-Toxic. it's ammo meant to be used at indoor ranges to keep the lead toxicity down. I'll be damned if i can figure out why they didn't just use a clean large pistol primer, but they didn't.
Now Winchester says you should not reload them, not because the brass is unsafe, but because the of the small primer pockets. As you found out, large pistol primers don't squeeze down too well. However, if you use a small pistol primer, they work just fine. I've done using my normal loads and they are OK. No pressure probems or anything like that. The big caveat is to NOT MIX THEM UP with regular brass that has large primer pockets. i realize that if you only have a few, keeping them separate can be a PITA, so whether you save them and load them is worth the trouble is something only you can decide.
In my case, no pun intended, I have so darn much regular .45 ACP brass that I just now throw them , the NTs, into the scrap brass bucket. When the bucket gets full, I head to the recyclers. Either way, they're not a total loss.
Paul B.