Would a ruger pc9 standard stock no pistol grip , with threaded barrel be legal ? Also would 15 round pistol mags be legal in that rifle  ? I have read the new law  what is or is not legal rifle vs pistol is confusing when  it comes to a pcc . My son is moving to Illinois this year and I am trying to figure out if I can give him my pcc or will I need to purchase a ban compliant version . Thank you

Well, technically, your son can bring anything with him and register it since he is moving here from out of state. I'm not sure I would personally recommend registering anything with Illinois but it's one option.

Also, I don't believe a non pistol grip pc9  would count under current ISP interpretations of the law, a caveat I have to add is that I don't believe their interpretation actually matches the law but it's in our favor, so whatever.

The magazines are kind of a gray area. He can similarly bring any capacity magazines he wants with him, but they can't be loaded anywhere but his property or other private property with permission. Then, rifles are limited to 10 rounds but pistols 15 so since this uses a pistol magazine I honestly don't know how that gets viewed since the law is a huge mess.

Thank you . I was very confused after reading the law ( probably a feature not a bug ) . I have him setup with a 1911 but I wanted him to have long gun option .  Pc9   would be the least scary  option I own  . I currently have the rifle setup with a flash hider  that I will remove .
The magazine was the most confusing , it being a rifle but the  magazine is for a pistol  .

Yeah, being threaded is no issue on a rifle but as you note the flash hider is, you can replace it with just a thread cap or even compensator since those aren't named.

My opinion on the magazine would be to get him the pistol that shares the magazines and just transport the two together with also at least 1 10 rd magazine. This way he can legally have 15 rd loaded magazines when transporting but nobody can claim they were just for the rifle.

Also, depending on where in Illinois he is going it's just possible nobody will care.

Correct me if I am wrong but it was my understanding that only " assault weapons " require registration .
I would give him either my g19 or 17  but he prefers a 1911 commander .
I guess I will be buying a few 10 round Glock magazines .

Yeah you don't have to register the "large capacity" magazines but because of the way the law is written:
- They have to be "pre-ban" or he has to bring them with him when he moves.
- No banned magazines can be loaded outside of your personal property or other private property without permission, so for example you may have had a ton of 17 rd magazines for a Glock 17 but you can't CC with those if you are leaving your property but 15 rd magazines would be ok.
- Large capacity magazines for a handgun are considered to be > 15 rds, large capacity magazines for a rifle are > 10 rds

The law is a huge mess, but this is one of the many gray areas - if it is a rifle that uses a pistol magazine and you don't have a pistol that takes those magazines then, theoretically, you can only take loaded 10 rd magazines with you when you go to the range (you can take high capacity magazines and load them at the range) or if you want to keep it in your car for protection. If you happen to also have the handgun that takes those same magazines then you should be fine keeping loaded 15 rd magazines when you travel.

Clear as mud and just one of the many, many, many problems with pica (the main one being that it exists in the first place).