Let’s break down firearm trigger actions.
Single action only (SAO) requires cocking the hammer before the trigger works. Double action/single action (DA/SA) has a long first pull that cocks the hammer, then lighter pulls after. Double action only (DAO) has no manual cocking; every pull is the same weight.
These terms describe hammer-fired guns specifically, a separate question from striker-fired vs. hammer-fired. Here's what each one means, with real examples from the Rock Island Armory and RIA-USA lineups.
Ask ten shooters whether they prefer a striker-fired pistol or a hammer-fired pistol, and you will get ten confident answers.
What’s actually the difference between the two firing types?
A striker-fired pistol uses an internal, spring-loaded striker to hit the primer of ammunition. A hammer-fired pistol uses a pivoting hammer that falls onto the firing pin, igniting the primer. The practical difference shows up in trigger feel, how ready the gun is to break the first shot, and firearm maintenance needs.
This choice is one of the first forks in the road when choosing a handgun, right up there with caliber and size. There is no universal winner in the striker-fired vs. hammer-fired debate, only the choice that fits how you shoot. Learn more with John McClain from Team Armscor.
You may be here looking for a direct answer to which is better. Here is the truth about the .45 ACP vs. 9mm firearm debate.
There is no one winner. There never has been, but there may be a right choice in ammo for your specific needs and situation. Team Armscor's John McClain knows both calibers well enough to help you deduce which caliber is right for you. So let's compare .45 ACP and 9mm ammo.