sear worn out on Tanfoglio

got a new Stock Master Tanfoglio a year ago, like it a lot-shoots well, low recoil, easy to strip and clean, but it was  DA/SA, so let's send it off to an outfit that specializes in Tans, and get it covered to SA.  Came back, shot well but 
had a very light trigger, got a multiple shots event once or twice, and some light strikes.  Got a heavier hammer spring from the outfit, had my local guy put it in. He said the trigger screw was misadjusted and the sear was getting damaged due to that. He set it correctly, and I went to the range- ran well, no problems, but my loads were a tad light, and a few did not eject.  I upped the load, went back to the range, and it ran well, but after about 40 rounds, I got  "multiple fire event", aka machine gun.  I took it back to my guy and he said the sear
was worn and I need a new one. 
This is the first time I have experienced this, and wonder if it is common?  I am getting schooled on how to tell
the correct setting, but it seems unlikely this should happen so soon after the conversion.  The pistol has maybe
3000 rounds total through it, probably 200 after the conversion.
A side benefit: the multiple rounds all went in the same hole!

Years ago, decades actually, I used to build TZ race guns. Very little aftermarket parts were available. Today there are lots!
Most new parts I’ve seen are excellent quality.
I find it hard to believe the sear is worn out. Several factors; hammer hook length, sear angle and sear spring pressure.
Light trigger jobs just from parts swapping is normally accident waiting to happen as you’re experiencing. Your local smith sounds like a parts changer vs gunsmith.
You should get someone who specializes in TZs to perform the work. Original gunsmith should warranty the work.
My 2 cents
Jon

The problem in my opinion is not the local gunsmith, but the "parts changer"
that did the conversion. He is supposedly a Tan expert, and his shop advertises that-he did not properly test the gun after his work, because he did not have a magazine so he could test fire it, thus the light strikes. the local smith makes custom 1911's and I would put him up against any I have seen.

Good luck.

Jon, I loaded 200 rounds and had time to think the issue through: In fairness to the owner, of the shop that did the conversion, his employee did the work-they did not have a 45 cal mag to test fire the gun and asked me if
I wanted to wait until they got one (odd, since they are a Tan dealer)- I said
go ahead and send it if you are ok with it.  It arrived with the light trigger and the mis-adjusted over travel screw.  If I had waited a few weeks for them to test fire it, they would have discovered the problem. I don't think the owner knew of the condition or he would not have sent it.

Light strikes are not coming from worn sear if doubling, automatic pistol, etc. Firing pin to light? Mainspring too light/too short? Firing pin channel clean? Headspace?
Can be related to several things.
Following, doubling, etc a whole different story. Check half cock not hitting the sear? Will slow down the hammer like hitting a speed bump. I can’t remember on TZ’s how close half cock is to the sear when passing by.
Jon

the only thing I "work on" in guns is changing recoil springs and sights.
Anything else I rely on an expert with a track record.  Happy to have found one.  I am way to old to learn new tricks.

Unlike Jon, I am not a gunsmith. But have coverted several EAA Witness pistols from DA/SA to SA. Always removed the disconnector, installed a SA Trigger, and filed the corner of the trigger to get the down leg of the Trigger return spring past the trigger. Never touched the sear, hammer hooks, or main spring.
When the gun was converted to SA was a SA trigger installed? You can easily tell by the shape and trigger location. A DA/SA Trigger is forward and is a curly que. A SA Trigger is curved and is closer to magwell when installed properly.

it was not SA before-a SA trigger was installed.  The problem was that the
overtravel screw on the trigger was too tight, and the hammer hook was rubbing the sear on every shot. Thus the sear got worn down and rounded,
which I saw at the shop today.  The rounded sear caused multiple fire.  If I had the knowledge to check if the hammer hooks were rubbing the sear, it
would have never happened, even with the very light trigger pull. I now know how to check for that.
I got a new sear and they are installing it now.

Jon Eulette wrote:Light strikes are not coming from worn sear if doubling, automatic pistol, etc. Firing pin to light? Mainspring too light/too short? Firing pin channel clean? Headspace?
Can be related to several things.
Following, doubling, etc a whole different story. Check half cock not hitting the sear? Will slow down the hammer like hitting a speed bump. I can’t remember on TZ’s how close half cock is to the sear when passing by.
Jon

I was not knowledgeable enough to know how to check for half cock hitting the sear, aka the speed bump.
The smith showed me how to do that, and I am the wiser for it.

Glad the issue is sorted. I like a little overtravel on Trigger, Would have loosed up the overtravel screw if it felt like a two stage trigger.
Patriot Defense used to be located close by. I had several Tanfos and had never heard of them. But with COVID they relocated to the DFW area.
I tried the PD reduced tension TRS in a conversion. Hated it. Ordered a couple from Eric Grauffel and did not like them. Soft trigger reset. Ended up ordering some normal tension from EEA.
They have parts, but do no advertise it. You have to order and they will respond if available ,quantity, and price. Some like TRS can only be ordered in low quality.
They say they are keeping parts for warranty work. But are not providing warranty work on the Tanfoglio products they sold. Last I checked, IFG has no parts.

Henning group has parts, no problem.
Has kits they install