What's your budget for the optic, and are you looking for more precision or speed of engagement? (I'm assuming speed/closer range given that you are thinking red dot) Vortex and Primary Arms make great price/value to quality options, but a bracket up does provide more durable and clear optics.

My guns that lives may depend on wear Eotechs or Aimpoints, and red dots like the Aimpoint PRO can be had for $350-$400 very lightly used, and the PRO is a solid optic. The H1 or T1 is great and much lighter, but usually a lot pricier. For those that like the eotech reticle, they can be paired with a cheap 3x magnifier and provide a lot of versatility, at the cost of weight. I bought a used Eotech 517 for around $300 a few years back, and have an EXPS 3 as well - both have been ultra reliable through some pretty tough conditions. There are other brands out there, but a huge number of combat guns run eotech or aimpoint as short range red dots. Battery life on the aimpoints cannot be beat (5 yrs run time), but I like the versatility of the standard eotech reticle. Can't go wrong with either IMO.

Definitely want to see pics when it's completed!