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Can I put an MK25 upper on a factory P226 .40 Lower?

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https://sigforum.com/eve/forums/a/tpc/f/150601935/m/2960092074

May 18, 2020, 12:53 AM
adam14
Can I put an MK25 upper on a factory P226 .40 Lower?
Dumb question as I should know this. Can I put my MK25 (9mm) upper on my factory P226 .40 S&W lower. Locking blocks look the same & the ejectors look darn close. Reason needed is b/c the 1913 rails on the MK25 lower won't work with all of my holster options.
Thank you very much!
May 18, 2020, 06:25 AM
fjgiie
It's the same Locking insert. The 9mm P226 carries a little longer Ejector.

Some swaps will work and some swaps will not let the slide go on. Give yours a try using the same ejector and if it fits it will probably shoot. If it needs an ejector you can put that on. We can find one of those.
May 18, 2020, 12:22 PM
adam14
Will do & Thank You very much... 9mm upper actually fits 40 lower perfectly & to my aging eyes the ejector are about the same... I'll shoot'er this week!
June 29, 2020, 06:08 PM
markstempski
quote:
Originally posted by adam14:
Will do & Thank You very much... 9mm upper actually fits 40 lower perfectly & to my aging eyes the ejector are about the same... I'll shoot'er this week!


If it does is officially a Frankensig. I don’t think using 9mm aftermarket barrels in a 40 should count but swapping slides certainly does.