BudsGunShop.com - Compatibility with 19 round magazines?

Matt, Absolutely 19 rounder will fit, you could even go to the 21 rounder.-------With 19+1 capacity (21+1 with extended bases), the P-10 F is unsurpassed in the striker-fired world

Yes it will work just fine with the 19 round mag the 10 round and 19 round gun are the same

Matt, yes Sir. the 10rd and 19rd Magazines are the same physical size with the 10rd Mag having an internal block so it can be sold in capacity restricted States. No worries with fit and function of the 19rd or +2 21rd Magazines.

Hi Matt, You can use any capacity without issue. Most magazines are just blocked for 10 rounds to make state compliant. I love this firearm and used to be one of my favs.