You bring up a very important issue in the "Revitalization of our Firearms Heritage."
Those of us who have grown up with firearms have to remember that many other families simply do not have this foundation. This is a foundation that has to be created prior to any family "activism."
While I come from a "firearms" family, I HAVE experienced something similar with my nephew.
My sister married a person with no firearms heritage. I would go so far as to say that he was anti-gun, but knew better than to openly state such in our household. However, my sister is a college professor and over the years became influenced by her collegues and her husband. She and her husband had a child.
Skip ahead a few years.
Said anti-gun husband ran off with a tramp. My sister had a rather scary situation at her work and actually called me about getting her CCW. She is now re-married to a very pro-firearms man. She has reevaluated her positions.
Now I am the Registered Gun "Nut" of our family. A couple years ago, I was concerned that my nephew was not getting the exposure that I got from my father.
So I went to Wal-Mart and got him a Red Rider BB gun.
I had a talk with Ginny (my sister) about it, and prior to getting her approval I explained the rules I would lay out for using the BB gun. We spoke quite a bit about it being a tool to start the process of learning firearms safety. With concerns, Ginny accepted my proposal.
Harrison (my nephew) has done VERY well with it, and is still highly supervised when using ANY firearm. Over the last couple years, he has shown enough care that we (my father and I) have gotten Harrison his own .410 single-shot Shotgun and a .22 Rimfire Cricket single-shot rifle-- both with my sister's approval.
In addition, he has used a .243 hunting, and he has been shooting a Saiga .308, an AK-47, an AR-15, and a LR-308-- not too bad for a 7 year old.
But NONE of this would have happened without the foundation of my father and I's background. Ginny had a certain degree of familiarity and confidence in us due to KNOWING our views on firearms safety.
So how does that help you?
Well... try this...
FIRST, come out of the closet. You have to let your family know your interest. They have to see you as a responsible firearms owner before they would consider exposing you to kids. Let it slip about your interest and then give it some time to "soak in."
Make SURE they know you have gone to safey instruction classes. You can always take the nephew again later. Don't be learning this stuff at the same time he is. If you are to be the adult, you should be seen as someone who KNOWS prior to the kid.
Now let that set in a while.
The NEXT step is to talk to his parents about VERY controlled shooting. This would be a good time to take them to the range.
I am almost more interested in how YOU handle this than how they handle it. They may well reject your offer. How do you handle it?
My suggestion is to accept whatever their decision is with NO argueing. It IS their kid. If you want to raise a kid a certain way, have your own.
But accepting their decision shows maturity, respect, and responsibility. That will go a LONG way towards changing their opinion going forward. It may even open the door for another chance at it later.
Once you come out of the closet and have let your family get comfortable with it, you may well win converts. Recently, I told my nephew that as soon as he is old enough, I would consider taking him to an Appleseed. After explaining it to my father, he wants to go as well.
The plan is now to pull his 5th wheel camper and have the three of us make a go at it as soon as Harrison is old enough. Side note... what is the min. age to go to an Appleseed?
At any rate, I hope this helped somehow.
-- John