One-handed shooting is where your pistol’s grip, your grip, trigger work, and recoil control all come together. Your pistol’s grip needs to fit you well if you are going to do the best trigger work, but it also needs to help you control recoil. With two hands on the gun, you have a fairly forgiving setup, but with only one hand on the gun, there is less room for error.
A Gen 5 Glock with no backstraps fits me well enough for trigger control as well as two handed recoil control. I can make it work with one hand, but the gun is really too big to be ideal. An HK P30L with a small backstrap and small side panels fits me better when only one hand is on it, so I can control recoil better with that gun. A 5″ Match PDP just showed up, and though I have not shot it yet, it seems to fit me even a hair better than the HK. I have high hopes for it.
When looking at fit, especially for one hand, I like to see as much of the rear of the pistol’s grip covered by my hand as possible. On the Glock, the lower left portion of the backstrap is exposed, as you can see in the pictures below.
On the HK, less is exposed, and maybe a hair less still on the PDP.
This allows more of my mass to be behind the gun in recoil, which helps control the gun in recoil better. It will still move to the support side in recoil since there is no hand there to stop it, but by curling my thumb down on the grip panel, rather than leaving it up as I do when shooting two-handed, I can mitigate that to some extent. If I further improve the situation by getting my body mass behind the gun and keeping my elbow down and behind the gun, rather than letting it drift out to the side, I can keep the gun tracking pretty straight up and down.
This not only improves my recoil control but with a red dot on the gun, allows me to return the dot to the target much more consistently. It is relatively easy to get fast confirmed hits (reactive), and it is really the only way of shooting one-handed that I have found that allows me to shoot predictively. Any deviation from straight up and down makes that more difficult.
The hand gripping the gun needs to grip harder than it would with two hands on the gun. This not only allows for a more stable platform but acts as a hedge against bad trigger work or anticipation. If you have not tried this, give it a shot. There is more to shooting well one-handed than this, but what I have laid out will go a long way to helping you make the hits.