The metallurgy of complete gun is wide ranging. The frame and slide must be made of mild steel that can withstand the shock of recoil, if made of hard steel it will fracture in a very short time. The barrel must be able to expand slightly or it will crack or just blow up into shrapnel. All pivot pins should be hardened in the 40 to 50 C scale due to the amount of wear and force they operate under. Sights should be of softer steel like the slide or they will sheer off. A hammer, sear and disconnector should be made of harder steel then the rest of the gun as they need to glide off each other, and maintain their shape and critical honed edges. If you use too soft of a steel on the action parts they will deform and change in shape with use and your trigger will change in the feel and break. High quality action parts should be hammer forged S7 tool steel or higher and should have a hardness of 50 to 60C.
Take a cheap 1911 and you will find soft action parts, if you rework these parts they will last a few thousand rounds and then the action changes as the soft steel changes. If you tuned the action to break at 3 lbs with an extra crisp break you will soon have a dangerous gun as the tolerances will not hold and the gun is going to double or worse and be unsafe. Look at all the high quality after market parts for the 1911; they are all true hard bar stock steel that will hold an edge that will out last the barrel. They are made that way for a reason, if you want a tuned action that is light and as crisp as a glass rod breaking you have to use the proper type and hardness of steel. Take the stock parts from an Auto Ordnance, rework them and within 5000 rounds you will have a full auto gun, replace the parts with EGW, Wilsons, Bear, Brown or the host of other quality parts on the market and work them to the exact same configuration that you did with the stock parts and they will out last the gun. They will never change and zero break in is needed.
The same holds true for a Sig Arms pistol, from the factory their sears and hammers are rated at 50C, it is the same from round one to round 1000000. Look at a S&W revolver, the hammer, sear and boss pins are hardened steel.
Can you get buy with soft parts? Sure you can but you can not tune them to the degree because you know they will peen and change. You can tune a good trigger with these but you can not tune an excellent trigger that is on the cutting edge. CZ parts are so soft that with one pass of a file will cut it, you should not be able to do this to a quality action part, and in fact you can not cut a 55C tool steel with a file without really trying, you need to use a stone to hone the proper geometry onto it.
True hard hammers and sears do not wear in over time and I personally would never tell a customer that they would, however I would say that about soft steel like the factory supplied action. If you own a CZ your trigger will improve to a point with both live and dry firing, most people will notice an improvement around the 500 round mark and it pretty much is done by 3000 rounds. It is not magical; it is metallurgy, a factual science of the properties and characteristics of different alloys. Soft steel will peen and burnish a smoother contact surface, thus the sear and hammer have less friction and the trigger feels better. Even if I stone matching surfaces on a stock sear and hammer it will still wear it self over a short period of time to a better feeling trigger, this is a fact and I don't know of any smith or metallurgist that will deny this fact. Steel on steel will wear or burnish, but the harder the steel the less it will do so provided it is preped with a glass like or ultra polished matching surface, the grain structure is much denser in hard S7 or higher steel, this is not magical it is factual. The rolling break of a CZ 97 is due to the way it leaves the factory, and the CZ 97B,75B, 75, 85C, 85B 40B and SP-01 all use the exact same action. If you want a rolling trigger that is great but most people prefer a crisp trigger that is more predictable and can be set from 1.75 lbs to 5 lbs, where you know that once the slack is taken up just a bit more pressure on the trigger will trip the sear, just like a 1911 or revolvers SA trigger with a custom action. Both are equally safe if properly done and both are equally unsafe if improperly done, and thats where you need to know the gunsmith who is doing the work and his/her reputation and experience with your make and model gun.
Metallurgy of the modern firearm is a very complicated science, well beyond my complete understanding. However I do know what parts and types of steel belong in a properly tuned action, I have seen this area grow over the past 25 years with improved parts strictly for the action workings of the modern firearm. I have been a guest of S&W and Sig Arms and spoken with their engineers, these people know the exact whats and whys of each part of a modern firearm. They are highly educated and design and engineer the best built firearms you can buy. They know what types of steel and alloys to use for each and every part of a firearm, and the companys they work for listen to them and produce what they specify. What I have taken away from my time with them is the proper steel and alloys to use in my area of firearms modification.
CZ makes a great gun but it could be improved greatly for just a few dollars more with the proper steel type and hardness for the action components. Then you could use and rely on these parts to tune them to the exact specifications of the individual owner. But thats just not the case at this point in time. If you want an action job with OEM parts we will do it, but it will not be tuned like those with a hard sear and soon to be available equally hard hammer. If stock is what you like thats great, but for those looking for better, stock will not do because physically it is not capable of it.
Jim
Miossi Gun Works LLC
702 Park Dr
Monticello, IA 52310
