On FN’s new 510 10mm…
I was on hand in 2017 when FN debuted the new FN 509 pistol, the product of more than 1 million rounds of testing and an offshoot of the gunmaker’s submission to the Army’s Modular Handgun System competition.

Based on its much-liked FNS Compact platform, that 9mm 17+1 capacity handgun was significantly beefed up to meet rigorous military requirements. Note the 24+1 round extendo
Then a year later came the announcement of the FN 509 Tactical, which was both suppressor and optics-ready with suppressor-height iron sights that co-witness with several MRDs on the market and was augmented with an extended 24-round magazine, as seen above.
Now, FN 509 Tactical has essentially grown to a full centimeter, so to speak, and has hit the market in the form of the 10mm FN 510, with all the same features but in the more commanding caliber.

Besides being suppressor and optics-ready, when it comes to the mags themselves, the FN 510 Tactical ships to most states with a standard flush-fit 15+1 round magazine and an extended 22+1 round mag. Those living in restricted areas have to make do with 10+1 round compliant capacity mags until they can repeal local prohibitions.
I’ve been kicking one around for the past couple of months and have a report in my column at Guns.com.