A Primary Arms micro dot would be my recommendation. Cheap, holds zero, durable enough for most purposes. You'll need a riser for it though.
When you're ready to spend a bit more I'd go for a Vortex Spitfire 3x. Durable, good warranty, and when your batteries fail, the reticle is still etched into the glass. The only downside is you need a screwdriver or actual tool to adjust height/windage - a cartridge rim won't do it.
When you're ready to spend a bit more I'd go for a Vortex Spitfire 3x. Durable, good warranty, and when your batteries fail, the reticle is still etched into the glass. The only downside is you need a screwdriver or actual tool to adjust height/windage - a cartridge rim won't do it.