A few years ago, I recommended the use of BB and/or Airsoft handguns as an ultra-low-cost training resource, to improve skill with a real handgun. I repeated that advice a couple of days ago in a new article. After that came out, I was challenged by a few shooters who insisted that "playing with a toy" could not possibly translate to usable shooting skills with a real firearm, and that I was "sucking this out of my thumb".
I'm never going to persuade everyone: but to those willing to watch with an open mind, here's about as much proof as you'll ever need. In Japan, private ownership of firearms is just about impossible, and severely restricted even for those with enough "pull" to get a permit. Therefore, the use of Airsoft guns as a sport has become very popular. There are even organized tours from Japan to the USA to allow those who've never fired a gun, to shoot one at a range here. Some businesses (e.g. in Las Vegas and elsewhere) actually make their living out of catering to the tourist shooter market (not only from Japan, of course). Those who come over here having familiarized themselves with firearms using Airsoft "toys" tend to do OK.
Some Japanese take this to extremes, participating in Airsoft championships that are right up there with the top matches in the USA in terms of the demands placed on shooters. You can see numerous videos of their efforts on YouTube. One such competitor recently came to the USA after exposure to that level of shooting. He'd never fired a real firearm in his life - only Airsoft weapons. Watch for yourself how he did when handed a real Glock and a real AR-15 - and then tell me, if you dare, that Airsoft experience doesn't translate to real firearms with only a minimum of transition training.
I think that video proves my point fairly conclusively. I'm nowhere near that young man's ability: age and physical infirmity have taken my level of skill down more than a few notches from when I learned to use firearms the hard way, in the bush warfare environment of Southern Africa. (I've written about Rhodesian-style "jungle walk" training before, most recently in this article. If you get the chance to try it, do so - it's worth it.) Even so, I benefit (and save a lot of money) from practicing with BB guns instead of real handguns. The former cost me less than 1c per round fired, compared to 4c-6c per round for decent-quality .22LR, 16c-17c per round for the cheapest bulk-pack brass-case 9mm target ammo, and 25c-26c per round for the ditto .45 ACP. Guess which option I can afford to shoot the most?
If I (or anyone else) can shred the center-face or center-mass area of a target, on demand, using BB or Airsoft weapons, what makes you think we can't do the same with something rather more useful for defensive purposes, given even a little transition training and practice - something I do at almost every range session?
I rest my case.