Interesting thread,...I can see why the step-by-step pictorials are popular. I've often considered doing this conversion to both the 4053 and to my Mauser M2 .40 which is another .40 built on a .45 frame that can well take the 10mm. But every time I look into performing the conversion, I wonder if there's an easier way.

For the record, I shoot almost no factory loaded ammunition whatsoever. Other than .22LR and military surplus ammo, all my shooting is done with personally loaded ammo. With that thought in mind, rather than the full conversion to 10mm I wonder if it wouldn't just be easier to long throat the .40S&W chamber, rip out the magazine spacer, and then long-load .40S&W to something closer to 10mm specs. I'm sure it would require at least the 180gr slug to do it, but that's what I'd be loading anyway. Continued shooting of standard .40 in the modified chamber would no longer be an issue and the long loaded souped up .40's wouldn't pose a danger in any unmodified pistol that couldn't feed them through the magazine.