While I suspect I might shoot SLOWER, I wouldn't expect my shooting wrong-handed to be any less proficient than my normal hand. Although, there may be issues with shooting due to the right-eye/left-eye dominance in conjunction with your handedness. Know what I mean?
The way I was taught to shoot makes it so I can pretty much shoot any handgun with the same accuracy, even if I've never shot the gun before. And I don't say that to brag or anything. The old dude who taught me to shoot was extremely picky, since I was a new shooter. His ways have just stuck with me. Multiple people have offered to let me shoot their new pistols/rifles at the range before and the results are generally the same. If I use the skills he taught me and remember the minutiae of those rules, I will always be accurate (enough) to hit the target.
<snipped>
I guess I need to hit the range next week and see what happens! Maybe I'll learn that I'm a giant doofus and need to practice more with my off-hand.
^ This, precisely. Until you actually try, you won't actually know.
And please don't take this the wrong way - until you've actually shot a timed and scored metric, freestyle (both hands), then with your dominant hand only, and then again with your non-dominant hand only, that "supposition" is really just that - it's just a guess.
It's the difference between bench-racing your buddies at the bar
versus lining your car up at the drag strip and making an actual pass: one is just a guess, the other is hard numbers.
The metric of distance, time, and score is the only way that you can cross-check yourself "in-reality."
The 10-10-10 (aka "The Test") by Ken Hackthorn/Larry Vickers is a very quick way to make this kind of assessment with no specialized target or range setup (10 yards is usually an easily obtainable range-distance, and shooters can even print-off free NRA B8 Repair Center targets via various online sources, just Google for it) , and the only stipulation is really that the range-rules allow for a faster pace than just "one shot per second."
Vickers 10-10-10, presented by Wilson Combat
^ This video takes you through "The Test."
Cannon has the shooter drawing from-concealment, but it can be modified to be run from virtually any ready-position.
Also, if range-rules do not allow for faster-paced shooting, you can simply aim to complete the drill at a part-time of 10 seconds (thus not abridging the one-shot-per-second rule), shooting instead to maximize your score.
If you prefer reading about The Test, instead, here's a great presentation by Greg Ellifritz:
https://www.activeresponsetraining.net/10-10-10-shooting-drill
So let me ask you all this question: If you are right-handed and right-eye dominant, and have to switch over to the left, do you also use your right eye or do you switch to the left? What is more proficient?
Your eye, the rear sight, the front sight, and the target have to be in a straight line. If you are right handed and right eye dominant and switch to your left hand, you may find yourself looking diagonally across the sights with your master eye. We test for eye dominance in all our classes. There are several workarounds. One is to simply close the master eye, thus forcing the non dominant eye to do the work. Another is to cant the gun at an angle to bring the sights into line with the master eye, or simply adjust your hold to bring the gun over in line. We are only talking about a couple inches. One of the advantages of red dot sights is it doesn't matter which eye is dominant, just put the dot on the target and shoot.
Different folks "see" differently - the principle, as
@HayesGreener noted (emphasis-added by me), is always the same, but how each unique shooter achieves that can be very different, because of physiologic differences alone.
In terms of eye-dominance, none of us are dominant to the same degree as another person. As a result, what may work well for one cross-dominant shooter may or may not work to an equal extent for another who is also cross-dominant.
Taking solely myself as an example, while I am cross-dominant (left eye, right hand), when using long-gun, as long as I have a rear sight or optic (magnified or otherwise), that device will "pull" my dominance enough that I experience no issues shooting both-eyes-open. Without that frame of reference - say, with a front-bead-only shotgun? I will completely miss high-left (using birdshot!), with both-eyes-open!!
For me, for handgun, when shooting around right-handed barricades, all I have to do is to simply "wink out" my dominant, left eye for a split second, and my right eye then takes over and I can return to both-eyes-open without risking impact to the barricade. When there are no obstacles, I simply present the gun to my dominant eye, which, at full-extension, is a shift of only around 1 inch.
Also for me, when my eyes get really tired -say, after a long day's worth of shooting- I occasionally will experience incomplete dominance: and how this manifests for me is that my vision will actually "double," with two sight pictures and two targets. Similar to barricade work, a quick hard-blink is all it takes for me to reset.
[ Bonus:
If you hit that link above that I posted for Ellifritz, you'll see that the picture he has opening that article is of Vickers. Vickers is also cross-dominant: he shoots pistol with his dominant hand, and prefers to tilt/cock his head over just a bit. He shoots rifle left-handed. Also, if you are interested, Brian Enos has written about cross-dominance (he is himself cross-dominant), and his discussion Forums is a great place to pick up more tips/hints, too. ]
Cross-dominance is really only an issue if the shooter insists on making an issue of it.
For every "disadvantage," the cross-dominant shooter can also experience undeniable
advantages.
Vickers is fond of saying that "training obviates awkwardness," particularly where it comes to re-trainng for left-handed long-gun shooting for left-eye-dominant shooters. Here, we can see that the speed of rifle-to-handgun transitions for these shooters is objectively faster than for same-side-dominant shooters. Similarly, for handgun, for those of us who are cross-dominant, barricades to our non-dominant side are easily cleared, where, particularly for novice/beginner same-side-dominant shooters, some additional work often needs to be put-in, in order to reach the same level of competency.
