Originally Posted by nick
... The magwell is another thing. P229 mags are a bit wider, so while P228 mags would work in P229 (they'll just rattle a bit), P229 mags will not work in P228, unless you open up the magwell a bit. I've confirmed it with my KTO frame - P228 mags would fit too tight (had to file it a bit), and P229 9mm mags wouldn't fit at all...
P226 mags fit the p228/229 (as seen on the web), but stick out