Originally Posted by
JonInWA
Thanks for chipping in on this, e_stern. I ran a TCU for years, and it didn't "feel funny" to me, but what I've picked up form others on the site here and on the berettaforum.net is that the circular cam piece can benefit from some judicious polishing, as apparently it can generate some rubbing on the frame or on the mounting pin (which resulted in the triggerpull glitches/lack of smoothness/funny feels). Apparently there were some allowable manufacturing (or QC) tolerance issues...
The advantages of the TCU was that it had had a far greater longevity (essentially lifetime-mine was run heavily for some 8-10 years) compared to the OEM lever-type trigger return spring, as the TCU utilized a coil spring. The TCU was also available in multiple triggerpull weights. I used the lighter one, which worked fine with the OEM triggerbar, but when I went to the Wilson Combat/Langdon triggerbar, the light TCU lacked sufficient "umph" for reset; so if you're going with a WC triggerbar, at a minimum I'd recommend their standard strength variant if you want to remain with a TCU. The OEM older lever-type trigger return springs that Beretta used were somewhat notorious for only lasting for some 2K triggerpull iterations, which is why the Border Patrol back in the day inveighed upon Wolff to come up with a longer-lasting replacement component for their issue Brigadiers. When I ran into the issues I experienced with insufficient reset strength with the Wilson/Langdon triggerbar, my fix was to replace the TCU with the Wilson replacement lever-type chrome silicone spring, which is doing just fine, in terms of smoothness, reset strength and longevity.
The advice on immediately replacing the locking block replacement is probably a good idea, especially if the pistol is used with an unknown provenance and/or roundcount/maintenance record (yeah, figure the odds on having any of those available on a turn-in gun...) ToddG and others knowledgeable were emphatic, however, that the replacement block be 1. From Beretta, and 2. Properly fitted, to ensure proper mating with the slide surfaces; otherwise undue eccentric stresses will be placed on the locking block's lugs, severely limiting their lifespan. DocGKR has also noted that there are substandard (non-Beretta) replacement blocks from external vendors that he'd personally witnessed on military guns; I have no idea if LEO armorers had access to them as well, but replacing the locking block is a good common-sense precaution, and pretty inexpensive.
In fairness to Beretta, probably 10 years or so ago, they did materially and archtecturally redesign the trigger return spring, so I believe the current forecasted lifespan for these updated springs is for 5K triggerpull iterations. If you've got any sort of a consistent dryfire program (or have the deep pockets/sponsorship for an in-depth live fire practice program), 5K triggerpulls comes up remarkably quickly. While replacing the spring isn't terribly difficult or time-consuming, if you want to go with a lever-type trigger return spring my recommendation is to go with the Wilson Combat chrome silicone one, as they claim it to be a lifetime spring. The one I personally installed in my 92D last year is running without complaint.
It's also probably a good idea to remove and clean out the extractor, as an amazing amount of GSR gunk can accumulate in it's niche. You can also use it's niche to scrub out the firing pin recess too, although that's been less of an issue/area of concern for me personally. While I have a WC chrome silicone replacement firing pin spring, the OEM one is chugging along quite nicely, so at least for the time being I'm leaving well enough alone (although if necessary, the removal of the firing pin safety and firing pin itself is drastically simplified on the 92D compared to other 92 models utilizing safety levers). If you remove the extractor, remember to re-stake the securing pin on top of the slide after replacing, to preclude the pin from wandering out.
Best, Jon