9 mm AND .22 LR on the same frame...
I do not see the point mentioned so far
Alistair, but I would suggest that you consider specifically pistols for which there is a factory (or a very good) .22 LR conversion.
As was already pointed out by others, nothing beats a .22 LR to learn the fundamentals. I would add that nothing beats a .22 LR conversion to perform the high-volume training that will lead to proficiency.
It would be a misunderstanding to discount .22 LR conversions. Some are indeed pieces of junk not worth owning, but many have been produced by the factories that produce the service pistols. For example, SIG made a .22 LR conversion for the 210. So did H&K for the P7. So did CZ for the 75. So did Colt for the 1911. Etc. etc.
Original factory .22 LR conversions show up from time to time on GunBroker.com. I have personally progressed tremendously practicing shooting IPSC on the same steel plates with a .22 LR Colt Ace similar in almost all respects to my Les Baer .45 1911. As yet another example, I have an Advantage Arms .22 LR conversion for each of my Glock 17, 19 and 21 and the kids have fired tens of thousands of tens of rounds through them.
You may need to select which ammo cycles well in which conversion (typically the solid 40 gr high energy ammo such as Remington Thunderbolt or Federal Tactical work better), but you will be amazed at the value they provide. This is to the point that I ended building my Colt Ace .22 LR conversion in a complete pistol on its own frame, to match my 45, when I got tired of constantly swapping the slides on a single frame.
The concept worked so well that I did the same with my Glock 17 when I started shooting IDPA.
.45 Les Baer (bottom) and .22 LR Colt Ace (top). The 22 LR upper started life as a conversion for the .45, but I used it so much that I ended up putting it on its own frame as a "clone" of the .45. Tens of thousands of .22 LR rounds got me at a decent level in .45 IPSC matches...
9 mm Glock 17 (bottom) and .22 LR Glock 17 (top). The 22 LR upper started life as a conversion for the 9, but I used it so much that I ended up putting it on its own frame as a "clone" of the 9. Ideally, I would have preferred a Gen 2 frame on the .22, as I have on the 9, for a perfect match, but it is not a significant discrepancy. Tens of thousands of .22 LR rounds got me at a decent level in 9 mm IDPA matches and made my kids redoubtably proficient with a pistol...
PS: do not be deterred by the horror stories about the trigger of the Glock. It is perfectly fine once you understand how it works... and this is probably THE best all-around 9 mm combat pistol in existence.