I have a AR15 with a flip up sight. I'm wondering if a red dot would be an upgrade for 100yds or less. I know this is an old type question but newly asked.

Absolutely! Your accuracy and time to get on target will improve greatly with a red dot optic at those ranges. I prefer aimpoint but eotech is also great. There's other, less expensive, options as well.

Yes. It would likely be a fairly substantial upgrade in most situations. Keep in mind the dot size varies in some red-dot sites, so your accuracy would also likely vary to a certain extent. (i.e. a site with a 4MOA dot versus a 2MOA dot)

It would be a revolutionary upgrade if you plan on ever shooting at night.

It is true. not accuracy only but speed also. Aimpoint has Micro H-1 with Blaser which I think is the best but also similar products work great. You should know that your Colt will kill a bit more birds but not more flies.

It's much easier to shoot with two eyes open with a red dot/halo style site.

Thanks for the input. I just missed a eotech 556 last week on our for sale so will be looking.

Also in that same price range look at an aimpoint patrol.

Aimpoint PRO is bad to the bone. And only $400.

looking at a Aimpoint comp ML2 that is for sale at 400.00 with mount. Sounds like a fair price. Looked up stats and should be a good match for my AR15. Do y'all have any comments on this product?