It's not generally necessary to lubricate the inner workings of the 3rd gen guns ... (with the disclaimer that some specific operating environments and conditions might result in specific recommendations being made by armorers or factory techs depending on mission applications)
Adding lubricants inside the frame can risk having it accumulate fouling, grit & whatnot with the potential of eventually accumulating into a sludge or goo that can interfere with normal operation and functioning. I've had to resolve more 'problems' resulting from excessive solvents & lubricants ending up places they needn't be and causing problems than I ever have actual 'gun' problems.
A case in point involves a fairly new (2-3 years old) 4566TSW which developed what was described as a failure of the hammer to remain cocked in single action. (Not good, obviously.) When the instructor who witnessed the events and user told me about the problem I looked at the gun. It was pretty much bone dry on the barrel & rails. That always makes me wonder how the rest of the gun is being maintained.
When I looked down inside the frame, though, it appeared grungy, wet & gooey (armorer term
). When I detail-stripped the gun I saw that some of the parts, like the sear, were gummed up and sticky. The sear spring appeared to be in good condition and as I cleaned off the sear nose, hammer and drawbar I couldn't see any visible damage. I suspected a cleanliness issue instead of a mechanical/breakage issue.
I noticed the firing pin channel, firing pin and firing pin spring were also wet, gooey & gummy. I'm surprised the user wasn't experiencing light strikes. I've had that happen a lot as well used (and poorly cleaned) guns accumulated ever increasing amounts of excessive liquid which would run into the firing pin channel and remain there when it couldn't run back out as easily as it ran in.
I gave the gun a good cleaning, lubricating the spots which required lubrication and leaving the rest of the gun clean and dry. The usual bench checks revealed normal function. I told the instructor and user to both go downrange and run a bunch of magazines (another armorer term) through the clean gun and tell me how it ran.
Surprise, surprise. The gun fed, fired & functioned exactly as designed and intended. The problem was gone.
Then I told the instructor and user to field strip the pistol and discussed the recommended manner of user level cleaning & lubrication, stressing the importance of NOT introducing excessive amounts of solvent and lubrication to places in the gun where it wasn't intended to go.
I'd like to say that this is an isolated occurrence, but that hasn't been my experience.
FWIW, the 'gritty' feeling often felt in a TDA trigger can cumulatively result from a number of things, really none of which are best resolved by just adding lubricant. The factory's Performance Center, or a skilled gunsmith familiar with S&W TDA pistols, can certainly work some wonders in cleaning up and refining 3rd gen guns.
The introduction of MIM hammers worked well in that respect, too, especially since the older machined hammers could have rounded surfaces of variable smoothness or roughness over which the sear nose would rub (in SA mode). I've seen some which made a shale outcropping look smooth by comparison.
A small drop of lubricant added to each side of the hammer where it rubs against the frame was added to the recommended lubrication spots between a couple of my earlier armorer classes for the 3rd gen guns, with the precaution not to use an excessive amount (which would run down and away from the sides of the hammer).
The use of different stainless alloys for different parts, as well as using carbon steel for different components and improvements in metallurgy, have resolved some of the concerns attributed to early stainless steel guns.
Naturally, not being there to look at your particular 4506 means I can't reasonably have any idea of what's happening with your gun, and I certainly don't claim to know, but those are just some general thoughts.
I'm certainly not a factory tech or a licensed gunsmith, but I paid a little attention during the 4 armorer classes I attended for the 3rd gen guns. I even took some notes.
If we lived close to each other I'd offer to inspect at your gun as a courtesy. Sorry.
Oiling Trigger Mechanism
Linear Mode
