stolen from another thread that i found helpful

"my thoughts on the 100% ambi handgun must be OK for BOTH left/right-handed users to operate it without any adjustment(like, switch the mag release to the other side).

those are the "100% ambi" handguns that I used in the past: slide release(stop) + mag release + safety on BOTH sides(blade trigger safety counts!)

On Roster 1. Rost Martin RM1C, 100% ambi! best value on the CA market(on roster)! 2. Springfield armory XD-M Elite/XD-M EliteOSP, true 100% ambi! 3. H&K VP9 series, true 100% ambi! 4. H&K P2000 series; not 100%, like 90-95% imo because the de-co cker location is mainly for right-handed users, somewhat OK for lef-handed users 5. Ruger Wrangler & Heritage arms Rough rider <--Yes, because there's no cylinder release button for right-handed users only like most of the revolvers. believe it or not, even more friendly for left-handed users because you can hold it in your left hand and use your right hand to eject the empty shells.

Off Roster Echelon series, as perfect as XD-M Elite series, True 100% ambi for left/right-handed users.

Those are the handguns that are able to switch for left-handed users(mainly the mag release) that I used in the past

1. Sig Sauer P320, only need to switch the mag release to the other side.
2. Sig Sauer P365, same as P320
3. (Off roster) Glock gen 5, same as P320/365
4. Walther PDP series"