So correct me if I'm wrong on this because I spent a fair amount of time trying to look at red dot options recently and was kind of bummed at this conclusion.
The Venom 3 MOA runs a CR 1632, so it's a top load battery but has a higher housing. Meaning cowitness on handguns is a lot harder. Which is fine because they marketed it as a long gun red dot.
The Viper 6 MOA has a really low housing designed for easier cowitness on handguns. They have an M&P CORE on the product page. That's great and all until you look at the battery and it uses a CR 2032. Unless they managed to do something all other red dot manufacturers have done and do a top load with CR 2032 that means you have to take the sight off to change batteries.
On the Venom product page they advertise that the sight doesnt need removal for battery change, but there is no such description on the Viper. Really a pain to have a handgun optic that needs to be removed off the mount and re-zeroed for every battery change.
I have a Fastfire 3 on one tactical and I really like it. It appears to work just fine and co-witnesses great with the suppressor height sights. I have a Vortex Venom on order with my FFL to mount it on the other tactical. I'm excited so we will see. Anyone have a pic of the FDE Tactical with the Venom mounted?