When I work up a new load with a new bullet type, I load up 10 dummy rounds (no powder, no primers), with the lightest taper crimp I can manage. I start with 1.300" OAL (quite long), and then adjust the seater incrementally back in .005 until they chamber reliably.
When chambering make sure to lock the slide back, insert the magazine, and release via the slide lever to make sure it gets the maximum force. Don't baby it forward - this can work for or against you. Sometimes if you do it by hand, rounds will stovepipe when fed "hard and fast", sometimes it'll make a round that otherwise stovepipe "glide in". So, lock the slide back and drop the slide lever. That way all variables are removed.
After you go through a cycle of them, check the OAL again for setback, and any noticeable rifling marks (and keep in mind, difficult extraction is a key indicator that you're seating your bullet IN to the lands, which isn't good). If you find any setback, it's pretty likely that your taper crimp is off. Each time you deepen the seating on your dummy rounds, the taper crimp will be applied to a "fresh" part of the bullet and it should have plenty of grip for additional testing.
When you're done, if the bullets are deformed (possible due to crimping), might want to discard them.
This also works for multiple firearms in the same caliber - just run the same batch through all of them. If it works for one, it may not in another. Sometimes you can't keep them all happy at once. (I.e. I have some loads with truncated cone bullets that feed in everything EXCEPT a Springfield XD45). If you have multiple handguns and find a scenario like that, when you load it, mark on each box "NOT FOR XXXX" - even if it's safe to run through it, you don't want your range practice ruined with FTF drills. (Well, MAYBE you do!).
Anyway, the logic behind the practice above is it will give you reliable cycling with the most case capacity. If your firearm is designed for +P loads, and you are adventurous enough to play a hair beyond max, that extra capacity could come in handy if you are using Unique...
(Note, I regularly run all of my loads at max in 45 ACP, and have gone a tad beyond on occasion, but everyone has to make their own decisions on risk vs. reward, and whether your firearm will stand up to it. I also have loaded and shot 40,000 45ACP reloads with Unique. I'm currently
cautiously working up loads in Bullseye because it's quite a bit more potent of a powder!)
