Hi and I would like to extend a warm welcome to the Forum. I frankly can't be of much help since what I know about long guns would fit a match book cover. I'm trying to learn myself, Just because I have always been as bad as anyone could be when it comes to using them, and I really want to learn before I start my dirt nap.
We do however have some really great long gunners here that I am sure will be happy to help. But I would give them a day before they offer any advice. Weekends are normally built around house work, the family and sports, folks don't generally have time to be online. Frankly I don't blame them at all, If I still had any of the first two things to do I would be doing that instead of this, And I'm not a TV sports fan, I like to see things up front and in person, much, much more fun in MHO.
What I can say is that A) you bought a really nice CZ long gun,
but you forgot to mention which version/model you bought. (forget that last bit, I just realized that you said 452 Trainer and I'm going to presume you are/were talking about this 452 CZ452 Special Military Training rifle. I may not know jack about using long guns at least not well, but I do know from chatting with other that your choice is a really good one for a First firearm, and B) My experience is with small arms up to Submachine full auto/select fire weapons and close in combat with Shotguns designed for that purpose, Which brings me to what I think I know about your question on Lead rounds. In any hand weapon I would strongly advise against using un-coated/non jacketed rounds unless you like cleaning your weapon a lot. Some folks do, it's what makes shooting so much fun, we all go at it differently in some way or another. The reason I say no is that you barrel will lead up much quicker than it would with semi-jacketed rounds. No offense but when I say lead up your barrel, I mean that sooner rather than later the lead will fill in the groves of you barrel, and in some case if not cleaned well and every time will fill in the groves of your barrel to the point that it becomes a smooth bore and no longer particularly accurate at any distance past say 20-30 feet I think? And getting that much lead out of a pistol is mostly an all day job, I shudder to think how long it work take to clear a rifle barrel, (think of lead in the lans and groves of you rifling as cholesterol in your veins and arteries. They fill up and getting them clean/cleared again is not fun.
That said, it's quite possible that in a .22 Cal weapon the round is so small that leading may not be the same problem it is with its larger cousins. Again there are better folks than I that can give you more information on the subject, and most likely do it with a Whole lot less jawing than I just did to say not much.
I really wanted mostly to welcome you as a new member here, and answer, or try to answer at least one of your questions so you would know that you are not being ignored are think we don't care since it may be later today or more like tomorrow before you get a response that answers all or most of your questions. I fully understand that you won't even have the weapon for another few days, but personally when I ask a question, I tend to champ at the bit waiting for an answer. Sometimes being a type A personality has some draw backs and I'm still working on learning how to chill, and not expect instant gratification of whatever it is I asked or want.