“Don’t shoot the subsonic round from a semi-auto. I used some squirrel hunting once looking for a “silent report” and wound up spending more time “digging” the failed spent shell ejection out of the rifle. Wasn’t enough charge to “kick ‘em” out on firing.”
There’s two ways to fix this. First, there are aftermarket lighter recoil springs available for most of the popular rimfire suppressor hosts, most notably the Ruger 10/22. The problem with that solution is that you need to go back to the OEM spring before shooting full-power ammunition, else the slide will be cycling too fast and could cause extraction or feeding problems. And if you shoot it that way a lot, you might end up “peening” the slide.
The second fix is to shoot a heavier bullet. It’s all down to that “equal and opposite reaction” thing, and a standard weight .22 bullet (30-40 grains) at 900 fps doesn’t make a whole lot of ‘oomph.’ There is (at least) one manufacturer selling 60-gr subsonic ammo, but a 60-gr .22 bullet is so long it won’t stabilize when fired from a 1:16 twist barrel, which is the ‘standard’ twist for (AFAIK all) factory rifles. The bespoke barrels for these 60-grainers are 1:9 twist. The up-side is that these aftermarket 1:9 barrels pretty much universally are notably more accurate than factory .22LR barrels. And while a lighter bullet doesn’t benefit from the tighter twist, it doesn’t suffer from it either.
Unfortunately Aguila quit manufacturing that 60 grain SSS ammo. :-(
A little dirty, but I liked it.
The heaviest factory .22 ammo I can find now is 45Gr.