Not only is Senco not what it used to be, neither are fasteners. I just went through this last week.
I have an old school NR83A 21 degree framing nailer, that is about 25 years old, so it lacks all the onboard sequential vs bump fire and depth of drive adjustments that the subsequent A2 and current A3 have. Yet, I wanted to use my old nailer to attach wood siding, which needs a smaller diameter and shorter nail, not a long framing sinker. As the photo below shows, I pimped my gun out with a nose bushing at the tip and an onsite Norgren regulator to control pressure to 77 lbs for a perfect flush head drive of .113 diameter ring shanks that are 2.375" long. Not pins, but the topic is now on current quality of nailers and collated nails.
I used to buy Senco nails 20 years ago, when Senco was the goto company for pnuematic fastening. I then bought Hitachi branded nails, figuring why not, I have a Hitachi gun. The Hitach nails were made in Oman. Ok, whatever. Then DeWalt started getting into the collated nail business with their brand, and offered a hot dipped galvanized, ESR-1539 rated, ASTM A153 rated, ACQ approved, ring shank in the lengths I needed, and they were made in Oman, just like the Hitachi nails. Prolly the exact same plant, because Oman is a very small country... how many nail manufacturing plants can they possibly have in the desert with a coastline?
But then my next case of DeWalt nails, exact same nails, said Made In China. Ok, let's take a closer look here, because I've been burned by poor Chinese quality too many times not to take a closer look. I picked up a case of HALSTEED collated nails of the same size, just not HDG, and not ring, but the HALSTEED nails met the LA RR 23633 code, and ESR1667, and one more code, 17something, that didn't apply to me, but was interesting all the same, as neither the DeWalt nor the Hitach branded nails were stated to meet those other codes.
Vice test. I put the Halsteed nail and the Dewalt nail in the vise. I first measured and marked each nail, so that their depth of insertion into the vise jaws would be exactly the same. With pliers, I bent each nail 90 degrees. Then I proceeded to bend them back and forth in 180 degree arcs to see how many bends it would take to fatigue the nail to separation. The Dewalt nail came apart in ONE bend. The Halsteed nail took SIX full bends to separate. I repeated the test a half a dozen times. Every construction guy who came by that day, I showed them the test. I had them do the test themselves. In every single instance, the Halsteed nail was able to be bent back and forth a minimum of four times, an average of five times, and a maximum of six times, back and forth before separation. The DeWalt branded nail, of the same length and diameter, could only be bent a maximum of two times back and forth before separation.
The Halsteed nails are Made In USA, by the way, by True Island Steel. Their website is horrible, so I had to call the company to have a list of all the collated nail sizes and coatings that Halsteed offers emailed to me. Hitachi, DeWalt, Senco, and the lot can all go pound sand. I want to pound nails that can survive a little earthquake shake now and again. I don't have time for recycled pot metal. I was really quite surprised at the difference, and feel terrible that I didn't start testing nails several years ago, when all this import stuff started dominating most of our readily available retail choices.
This may or may not apply to the quality of pins that the OP seeks, but it might be useful for anyone reading to know that there was a 3 to 5 times difference in the separation cycles between one branded nail made overseas vs another made domestically.