P226 upper swap/caliber change

[Sero Sed Serio]

I own SIGs. A lot of them. My EDC is a P226 9mm DAK, in large part because the excellent JMCK AIWB Wing Claw 2.5 hides it better than a standard AIWB holster hides my P2000 (although this may change to a P229 9mm DAK shortly as I have a Wing Claw 2.5 inbound for it).

I recently picked up an all-stainless P226 9mm DA/SA (U 671 XXX). I also have an alloy P226 .357 DAK gun (U 755 XXX). Both are low round count guns. I'm toying around with the idea of swapping the slides and locking blocks, so I would have a second alloy P226 9mm DAK as a backup to my EDC (I already have a dedicated training P229 DAK that I consider close enough to my P226 DAK to serve as my primary shooting gun) and an all-stainless DA/SA .357 to tame the increased recoil of the .357 round. I would want both guns to be reliable enough for carry.

My understanding of SIG caliber exchanges for the P226 is that I'm good to go with an entire upper swap, as well as changing the locking block. Is this correct? If I do so, can I end up with a gun that is reliable enough for carry? (I would properly vet both guns before even considering carrying them). Or is this a stupid idea, and I should put down all the SIG parts and slowly back away?

[rathos]

226 you shouldn't need to swap the locking block. Those were the same in any caliber. DAK hammers and DA/SA hammers are different, however I am not sure it would make a difference.

[taadski]

Rathos is correct. The locking blocks for the 226 are the same across calibers and don't need to be switched.

I've played legos with the Sig P series pistols pretty extensively over the years. Moving complete uppers around (same model) has been a non-issue in my experience. That said, as you mentioned, I'd properly vet ANY new pistol or combination prior to relying on it for carry.