I NEVER said there are no complaints about Uggies, Larry. In light of how many of them are out there, I think complaints about them are in the same class as complaints about Ruger Red Labels. You hear some.
Yes, there are a few duds.
The only US made double I've ever owned and used were a Western Arms and a Tobin. The Tobin has a pair of little strikers just like a Spanish guns. On my 16, one had been replaced. The Western Arms went down the road after about a season, nothing wrong except it had a single trigger I couldn't get my head wrapped around. I have no clue how a Western Arms gun is fired, but, whatever system they use is tough, and complaints about them not going boom are not common. I'm going to try a Nitro Special, soon, in 16 gauge, just to say I did, I guess, because I certainly don't need it. I have no idea which American guns use integral striker/hammers, but, American guns are usually pretty robust on the inside. Might be the price one pays for those lightweight English 700 guns.
A Darne uses a striker that is on the order of a Mauser striker, Larry. Quite robust, and, not comparable in any way to the discussion at hand. Never seen or heard about one breaking, here or in Europe. The component most broken on a Darne R is the main spring, and it usually breaks from a monkey using a tool on it. V Darnes break trigger return springs, five to ten minute job to repair, tops. You can use the side that isn't broken as a sample to bend up a new one, out of music wire. Neither of these Darne issues is one I have ever come across, it is what the factory told me to watch out for, and gave me spare parts for.
I still have the spare parts. Oh, and if the V breaks a trigger return spring, you can still use both barrels of the gun.
I don't recall this being a discussion about Darnes, however, Larry. Try to stay on topic.
Speaking of looking at the one that isn't broken, that is how one would come up with dimensions for a new striker, assuming one has access to a lathe. I've tested my spares for the Uggie, they work just fine, but, Cole Haugh supplied them. There really isn't much to them Larry, they would be simple to produce. I don't believe a nail would actually work, Larry. In any gun. Try it on one of your guns, and let us know.
Kyrie's list had a bunch of different guns that weren't Uggies on it, Larry. The only Spanish guns I look at, in passing, or with cash in hand, are/were Uggies. I have no desire to become fluent in Spanish gun makers outside of Ugartechea, and no further with them then the basic model 30 and similar guns. I think I said that already. I pointed out two gunbroker Uggie listings, one with a bid at $550, one at $600. Close enough to what I paid for mine, certainly not double in price.
The guns I'm talking about here are just generic, using grade boxlocks, and that is the only perspective I have on Spanish guns, Larry. My gun, and a few very similar to it, are the only experience I have with anything Spanish. I haven't had to ask, but, just about anything that ever broke inside of it would likely be something Cole Haugh has hanging around his shop. For my "canoe gun" there is a lot to like about that.

Best,
Ted