Contents show. Best 300 Blackout Pistol Red Dot Reviews. #1) Holosun HS510C. #2) Trijicon MRO 1×25 Red Dot Sight. #3) SIG SAUER ROMEO3 1×25 mm Open-Reflex Sight. #4) Aimpoint PRO Patrol Rifle Optic. #5) Vortex Crossfire Red Dot. Wrap-Up. The Trijicon SRO is available in three different reticle size options, all utilizing a red illuminating LED. 1 MOA red dot model SRO1.; 2.5 MOA red dot model SRO2.; 5 MOA red dot model SRO3.; The front lens of the optic is extremely clear, making for a crisp reticle dot and a sharp target image — all of this in a large viewing window, one of the best features of the SRO. Vortex Optics – Crossfire Red Dot Sight. The Crossfire is Vortex’s most affordable red dot sight. It gives you a no-nonsense sighting system to install on your AR-15 or any other weapon you might want to attach it to. Coming in comfortably under $200, this is an ideal red dot sight for the shooter on a budget.