When "upgrading" triggers using factory Savage be careful with what you are buying. There is one trigger, two sears, and two springs. The non PTA actions come with one sear and the PTA comes with a different sear. The non PTA actions will have a "varmint" spring which is lighter or the non varmint spring which is heavier. The "varmint" spring is also what is in the PTAs. If you are wanting a PTA "trigger" what you really need is the sear and I have seen people only selling the trigger(as the PTA trigger) many times. As far as actions go with current production(and most past) two digits such as 11 or 12 are short actions and three digits such as 111 or 112 are long. The third digit is what Savage uses to distinguish between "varmint" and "hunting" and stainless, blued, or matte. The letters after are geared towards the stock and magazine configuration. Having said that Savage is very bad at being consistent and variations may occur.