I tried this in a couple of guns after reading this thread. In a tso the tanfoglio sear spring added a tiny bit to the pull weight but did give the trigger pull a more definitive wall and a slightly more crisp break. An overall improvement for my trigger preferences.
Second gun, 75B with a cz comp hammer and 13 lb recoil spring, this combination is already significantly better than the factory parts that come in this gun but the sa doesn’t have a very defined wall and the break is good but isn’t all that crisp maybe a 7/10 on my subjective crispiness scale. After the four coil tanfo spring install the break is more crisp for sure, I’d give it an 8.8/10, with a more defined wall and I’m seeing 4-5 oz heavier. I’m not noticing a difference in reset or DA pull on my gun. But in both of these guns this is for sure a worthwhile upgrade for what I like in a trigger.
Out of curiosity I installed one of the cz sear springs into The Tanfo and it has a noticeably lighter trigger pull in sa maybe even more dramatic than 1/4 lb but no definite wall and a less crisp. I prefer it slightly heavier with crisper break. So it got its spring back and I’ll be ordering two more for the czs.
A quick note on reset, years ago when I installed the parts in the 75, I didn’t like the feel of the reset either with the reduced power trs. CZC sold a heavy trs that is supposed to withstand breakage better and gives a snappier reset at the expense of reduced pull weight. I settled on the heavier trs spring and run a 13 lb hammer, now with the tanfo four coiler for the sear I’m at about 3.25 lbs SA. While this might be too heavy for some the gun feels more predictable and responsive. I may now drop to the 11 lb spring for the hammer and see if that might be the ideal combination.
Thanks for the ideas.