I currently have an EO mounted for general use/close quarters stuff.  I want to purchase another optic that will give me more flexibility for target shooting and was interested in variable optics.

Would it be useless to go with higher magnification?  What is the maximum magnification that you would put on an M4?  Would I be better off with fixed magnification?  Any recommendations?

Again this won't be my primary optic.  Just for fun.  Thanks for your input.  

For variable you can't go wrong with Nightforce. Either of these would work for a GP/target optic.

If you want fixed power Trijicon would be the way to go.

I would recomend the Nightforce 1-4x24 NXS, I believe this optic is the best of both worlds, however at a steep price.

I have an IOR 2-12 scope and it is perfect.  It has the short and long range that I need for everything.

Thanks for the replies.  

My main question, though:  Is  their a certain amount of mag that is overkill for an M4?  I know that others  have some big mag on longer match barrels.  I thought I read another thread saying that x mag was ridiculous on a shorter barreled AR for some reason.  Just wanted to know the reason and what that threshold was.

Maybe 1-4X is the ticket?

Quoted: For variable you can't go wrong with Nightforce. Either of these would work for a GP/target optic. If you want fixed power Trijicon would be the way to go. I would recomend the Nightforce 1-4x24 NXS, I believe this optic is the best of both worlds, however at a steep price.

Have you tried the Nightforce 1-4X you reccomend?  I have tried to purchase one for a solid year now and still cant find one for sale.  I did not know they released them.  Can you post a review if you have one?  Did they fix the dim reticle problems?  That was why I was saving the extra $800 for a S&B Short Dot over the Nightforce but if they fixed that reticle illumination problem I would love to save money.