IF it is a new gun, I'll relate my story with the UC2.
Mine, new out of the box, would not fire Sig Sauer or Sellers ammo. The first, and many other rounds, would FTF and jam no matter the brand of mag or how clean it was or wasn't. FYI, I have found that the WC mags are far worse than even the cheapest cheap mag out there. I like the design, but the plastic feed gets sticky/jumpy over time.
The gun would feed GA Arms factory reloads all day long with no issues whatsoever. After many complaints here, and some very nasty remarks, I contacted Kimber. Note: this was during the height of the Covid craziness. They shipped me 3 new recoil spring units. I stiped the gun, soaked everything overnight in Hoppes 9, wiped and scrubbed it down, lubed and reassembled with the new recoil spring unit.
The gun has fired everything I've put through it except when I use a Wilson combat mag. They fail to feed on the 4 or fifth round every so often. I'm guessing mine came equipped with either a 9mm spring unit or a faulty one from the factory. I'm not actually sure there is even a difference in the 9mm and .45 springs. Don't really care now that it runs consistently. Mine has well over 3,000 rounds through it. While its not my favorite .45 to shoot, it is my EDC.
I have since put in a metal mainspring housing and added magwell. I'm ditching my WC mags and sticking to the Kimber Pro mags for carry. I'll still use them at the range. And before someone mentions it, yes, I clean my mags as well.
Slingshotting the slide is not the "correct" or "proper" way to to chamber a first round. It might be your prefered way and the way you train, and that's fine, but dropping the slide via the slide stop is every bit as proper and and correct. If someone like Ken Hackathorn or Bill Wilson say it's okay, I'll take their word for it. Just don't do it on an empty chamber. (There is a WC Youtube video where they discuss this exact subject.)
Lord knows I'm no expert but I do research things and not just on the internet! I've spoken to many LEOS who carried 1911's as well as many service members who have carried them. And, I've discussed things here. Usually I sound like some crazy noob, but don't let my stupid questions fool you.
I'm just new to the 1911.