Does anyone know for sure if Mec-gar makes a +2 extension that will work with the standard P229-1 mags? I have a number of their +2 mags and if you take them apart the extension seems to fit the regular sig mag fine but it looks like the springs are different lengths. They are off by 1 full coil. If you know where to buy ones that you know work please let me know, post a link, etc ...