Hi there!
The Tanfoglio Witness is generally a quality weapon. I own a Witness Match. However, like a lot of pistols they have some quarks, mostly related to engineering changes made in 2005. That's when the smaller sized Witness was discontinued (TZ-75, it's the size of a CZ-75B) and the somewhat larger Witness was retained.
I have experimented extensively with the weapon in .40 S&W, 10mm, and .38 Super.
Note the slide in your photo. See how round it is? That was one of the engineering changes, material removed from the slide. The round slides, especially, can crack particularly in 10mm and .45 ACP.
I own three Witness slides. The one that came with my Match, an older slide from Numrich, and a newly designed slide from the factory. (I don't personally own the more problematic "round" slide as shown.)
The newest slide is from EAA directly and is heavier and thicker than the other two, so hopefully they've fixed the problem. Be careful, though, the Numrich slide looks like the one I ordered from EAA, but when you examine it closer the current product EAA slide is thicker.
The current issue is with the magazines.
- 9mm and .40 S&W have feeding problems and trust me, I've been through all of the new and old style mags. The problem is feeding a short cartridge through a long action. It's not hard to "fix" the .40 S&W mags, but I don't know of a satisfactory solution for 9mm.
- 10mm mags were more reliable, but would also occasionally jam. Don't worry there's a fix and it's easy.
- .38 Super and .45 ACP mags are generally considered good from the factory. However, Mec-Gar makes magazines for the Witness in these two calibers and they're quite high quality. My .38 Super mags hold 18 rounds (yes, 18) and feed perfectly.
The magazine fix: For perfect feeding in 10mm/.40 S&W mags, should you have a problem, I take the stock mag body and replace the follower and spring with the follower and spring from one of the Mec-Gar mags.
Mec-Gar apparently uses the same spring and follower for their .38 Super and .45 ACP mags. Magazine capacity is reduced to "only" 14 rounds, but it's worth it for reliable function. Because .40 S&W is derived from the 10mm it works very well for both calibers.
Forget about the 9mm version. You might get a good mag you might not and no aftermarket is available. Don't waste your money on Wolff mag springs for the fullsize mags, I find they won't fix the problem and seem to be a bit short.
In 10mm the recoil is only moderate, less than my Glock 20. However, it throws brass into orbit even with a heavier spring. Some say it's best to shorten the extractor for 10mm, or you could just live with it.
That brings me to the recoil springs, which are somewhat underpowered for the Witness line. That's not uncommon for a lot of pistols. Get a package of Wolff springs and use the spring that matches your load.
So, in summary...
- Some older .45 ACP and 10mm pistols had longevity problems (slide cracking), especially with the "round slide" show in your photo.
- New, thicker slides have been made available recently that I assume were designed to fix the problem.
- Feeding problems are common with the Sabatti magazines supplied with current Witness pistols in 9mm, .40 S&W and sometimes in 10mm.
- There is an easy fix for .40 S&W/10mm pistols and aftermarket mags for .38 Super and .45 ACP. Unless you like to tinker, then skip the 9mm and get a CZ-75B or wait until the factory comes out with a fix.
- Witness pistols tend to be a little under sprung.
- .38 Super is my favorite caliber for the Witness line. 18 rounds in a fullsize mag, cocked and locked carry (easily converted to single action), feeds great, good accuracy, excellent ergonomics and no real longevity issues.
I hope this helps!