Today I finally showed her pics of the m&p15-22 that I bought and have yet to collect from the FFL location.
She pinched a fit greater than I would have predicted but I think I am at a place where she will be OK with keeping it. Phew!
First and foremost, I suspect her reaction is due to the media misinformation, propaganda campaign for increased gun control legislation. The anti-gun biased rhetoric and negative connotative words set off an emotional reaction.
https://www.youtube.com/watch?v=q2riOiBaZrg
The challenge is to gently persuade her to your viewpoint. When a belief is challenged, the normal reaction is to dig in and hold ground. Guide her so that she can come to the realization, on her own, that the M&P 15-22 in function is exactly the same as the non-threatening Ruger 10/22.
Maybe a friend has a plain jane, stock 10/22 you can borrow. Persuade your wife to go to the range with you, and shoot the 10/22 off hand. Make the range session very positive and fun, like an old-school trip to the bowling alley.
When she's accustomed to the visually non-threatening, traditional appearance 10/22 with it's 10-round rotary magazine, then introduce the 15-22.
Hopefully she'll see for herself that there is no difference in the basic semi-auto function between the two. She'll see that the differences are cosmetic and ergonomic.
I took a female cousin to the range. She bought into the anti-gun media propaganda for years, and was 100% anti-gun. When I disclosed to her that I'm a firearms enthusiast, she passionately tried to argue the anti-gun position. Her perspective was that I was putting myself in danger, and she wanted to protect me. I appreciated that.
I told her that her statements would carry more weight with me if she gained first hand experience shooting a firearm. She accepted the challenge with trepidation. I took her to the range. I taught her safe firearms handling, and basic shooting fundamentals. We progressed:
Ruger 10/22 > Ruger MKIII > S&W M&P 22 pistol > S&W M&P 9fs.
To her amazement, she found she enjoyed shooting and she was a naturally good shot. She asked if we could go to the range again the next week. We did. After that range session, she applied for an Illinois F.O.I.D. card. When the card arrived, I gave her a gift certificate to use at the LGS to help offset the cost of her first firearm.
Now she owns a Browning Buckmark and a Glock 19 Gen4. She's now a member of the NRA.