I always take an opportunity to introuduce kids to guns if I can, as I feel these days kids just don't get exposed to them like they used to, only being bombarded with BS news stories.

My nephew, who has never shot a gun before, and 2 of his friends, both 17, are coming up from Mass to New Hampshire to look over a guitar amp I have for sale, and I thought since he's never shot a gun before, I'd take them to the range to try out my AR, SAR-1, Glock, etc...

I know my sister is fine with this, but I started wondering as one of the other kids mother's works for a lawyer, if I'm crossing some legal boundary.

My nephew is enthusiastic about this, and I'm sure the other 2 kids, being teenaged guys, would find it a really fun thing to do as well.

Is there anything illegal I would be doing by taking them shooting, without their parents knowledge, assuming they don't discuss it with their parents first?

Seems like a silly question, but kids don't get bb guns and .22's when they're 12 anymore.  Many grow up to full adulthood and have never tried shooting at all.  

I can't see how.  I've taken "kids" (under age) shooting many times.  I ALWAYS get their parents permission at least on the phone (as you have) and we've always had a great time.  Not ONCE have I been denied. There's nothing that says you can't do that under proper circumstances.  I take them to my club's range, every one has glasses and muffs, and we go one at a time to the shooting positions.  Each "kid" gets a hands-on lesson about the firearm (rifle or pistol) and they get strict instructions from me about the shooting commands.  For instance If they get a "hang fire" they are to stand in their shooting position until I decide to clear the weapon.  It's happened from time to time.

Since my kids were in highschool, their friends have always asked to go to the range if we have a few hours when they visited.  Some have continued their interest and joined the military.  Some have even served in Bosnia and Iraq.  Just two weekends ago, one of them dropped by and asked if they could hit my range with me to "practice" a bit since they were being deployed to Iraq in two weeks.  You must know that I dropped everything and we spent a couple of hours burning my ammo. It's the least I could do.  Turns out this fella was designated "expert" and took my AR and cleaned the targets (cut up 4" CPVC pipe, 12" tall) at 100 yards without a miss with a weapon he hadn't fired before!  I was extremely impressed.  He's only seen an AK47 before so we took that too, shoot it, and tore it down so he knew how to assemble one.  I also took my M14s set up just as he'd find one in the field and he enjoyed playing with it, too.  He was very appreciative.  

Introducing kiddos to the wonderful world of competitive shooting is exciting . Also, it gives me the opportunity to teach them about what to do if they discover a firearm someplace.  It also give them an excellent understanding about real life shooting compared to what they've seen on television.

So, Ed-p (my brother's name btw) you are to be commended in your efforts.  I'm an NRA certified pistol and rifle instructor and C&R holder.  I got those credidentials just so I could help the scouts and interested parties (primarily youths) aquaint themselves with firearms and not to teach classes per se.  I also do "talks" to civic groups about firearms and bring my entire extensive collection of semi-autos to the talks and after the "lecture" allow anyone in attendance to handle the pieces.....with supervision.  These talks have always been very well received.  The smiles it produces are worth every minute of preparation.  Young and old, veterans and civilians have all been impressed with the hardware.  

Good luck with this.  As long as the parents know that you're taking their child to the range and you have everything under your control, have FUN.  There's nothing more enjoyable than seeing a newbie shooting their first rifle or pistol and having a good time.

Rome