I’ve read various comments about the Vortex Strikefire II and the consensus is that it a good choice for rimfire Steel challenge on a M&P 15-22. I just can decide which one to order, the red/green dot or bright red dot. I can’t view them and will have to be a mail order deal. Can someone who shoots this match advise their thoughts or comments to help me decide and not make a mistake? I am late 50’s and eyes are OK but not 100% anymore I wear shooting glasses to bring focal point to the sights on my pistols rather than distance which my normal glasses assist with.
Appreciate all your comments.

That's the kind of advice given by posters that don't really shoot Rimfire Challenge or Steel Challenge.
For Rimfire challenge or steel challenge you want a bigger tube if you really want a tube type optic and a bigger dot. The "window" type red dots with big dots (12 or 16 minute) work better. Best of the bunch on a 15-22 is a C-more Railway. Big window, excellent optically, replaceable dot modules and it's the right height without a riser.

I'm 66 and definitely in the "old eyes" category and do shoot steel and rimfire challenge. C-mores are great. They have optically good (glass) lenses and replaceable dot modules so you can change dot size. Downside to the C-more is windage and elevation adjustments that don't have clicks. I have Ultradot Match dot IIs for when I want adjustability. Is your gun mostly for plinking or is it for shooting steel matches? If you mostly plink and occaisionally shoot steel use what you like. If you're serious about shooting steel get a C-more.

I don't shoot matches but have the red/green stikefire II that I use on 15-22. You can adjust the brightness of the dot if I recall correctly. I prefer the green dot over the red for target and plinking. I just seem to see it better.

I shot a 10-22 with a Strikefire in a medium 30mm Vortex ring most of last year in steel challenge. It will work, but you will likely be faster with something else. The Strikefire a very good red dot, its just heavy and kind of bulky to see around for speed shooting. I went to a C-More railway with an 8MOA dot on that gun. The Tactical Railway might be a better fit on a 15-22 due to the bit taller height and the straight stock. Less bulky, still a large window, and easy to shoot with both eyes open. I never did to bad with the Strikefire, but I did get faster with the C-more. For a rifle, don't underestimate the micro dots either. You still pick up the dot fast since its a rifle and not a pistol. You have cheek purchase there and you will pull right to it. They weigh less, and can be had in larger dot sizes depending on what you get.

I never use my green dot on my Strikefire. Don't know why, just never do. For what you are talking about though, the C-more is kind of the popular thing. And the bonus on it is once you have the sight, different MOA modules are like $50 each. Can basically have from a 2MOA to a 16MO and keep the same basic site. Optics Planet is the best place to get those if they are in stock and there is a coupon available. After that, Wirthwein Guns or Shooters Connection.

Only downside to me is that the C-more is kind of a pain to zero. Have taken up to 50rds to get it where I want it. A click tube like a Strikefire I can generally get on with 10-15rds.