Question 1: The mk25 looks great to me, since it comes with 4 mags and has the anti-corrosion coated internals. I can only get my hands on the normal versions (e26r-9-bss) locally, and like the triggers on them. Does the anti-corrosion coating in the mk25's fire controls have an effect on the trigger pull at all?
I believe the anti-corrosion coating is part of a casehardening-like process that surface hardens the parts. I would expect it may actually improve the trigger
Question(s) 2: If I don't get the mk25, I am considering getting the Classic .22 Beavertail and then getting a 9mm X-Change kit to have 2 guns in one for about the same price as a normal 226, and significantly less than the Enhanced Elite model 226. Questions: is the frame really the same between the .22 versions and the others? Would the cobbled together 9mm made out of the .22 Beavertail and the X-Change kit be basically the same as the Enhanced Elite? I would love to hear from someone with firsthand experience.
I believe the same frames are used for the .22 and centerfire. You may be able to save money getting the .22 and then the centerfire conversion slide and barrel.
Question 3: Would I be better off getting the mk25 and then getting the .22LR X-Change kit for it?
Question 4: Do Sig's p226 .22LR models run on bulk ammo, or would I need to get high velocity rounds for them?
I had to break in my .22 conversion with a couple of hundred rounds of high speed stuff before it would cycle normally with standard speed stuff. During the break-in it would cycle the standard speed stuff, but it felt like it was cycling in slow motion. Now it is fine. Bulk ammo is usually high speed stuff.
Question 5: I am also interested in the models with stainless instead of aluminum frames, but have heard comments that the stainless frames throw off the balance of the pistol. Has anyone had any experience with that?
My 226 is an older stainless gun in 9mm. I got a .22 conversion for it soon after they came out a few years ago. More recently I got a blued conversion slide with a .357 SIG barrel and then got a spare .40 S&W barrel. They all play together very well and the .357 SIG is particularly accurate. I like the weight and balance of the stainless gun and I have never gotten hammer bite with the short tang, so, unlike the SIG210, I don’t see the urgency to get one with the extended tang.
With the conversions, they make a 9mm barrel that is supposed to work with the .357SIG/.40S&W slide. I haven't tried it myself, but if you wanted to, you could get a .22 gun, .357 SIG centerfire conversion, and 9mm and .40 S&W conversion barrels and be completely covered. I like to shoot 9mm because it is cheap. If you think you might want the .357 SIG, you might want to get it with the slide because I think the .40 S&W barrel is easier to find than the .357 SIG barrel by itself. The .357 SIG and .40 S&W use the same slide, recoil spring and mags.