maybe try,
you will need to go to the sites & look it up
www.midwayusa.com
or
www.basspro.com
www.cabelas.com
or
www.palmettostatearmory.com
or
www.luckygunner.com
or
www.sportsman.com (Sportsman's Warehouse)
or
www.bulkammo.com
maybe start loading your own
Hornady (or Frankford Arsenal) get the books & has all you need,
but it will cost 100+ times more to get the reloading equipment
but get the brass & primer & bullets,
do your own, for as long as you like
I haven't shot a .22 short or LR in years/decades now
have an old trusty Ruger 10/22 I got when I was 10
or my Colt Bushmaster
I never shot caps, rarely any subsonic stuff either,
seemed like why (?) bother
(I have a .177 pellet 900ft to 1200+ per/sec.
air riffle for that stuff, deadly inside 30-40 yards)
the shorts are so dang quiet anyway
I know you want them quite not much penetration etc.
unless you're doing something illegal, you shouldn't be doing
want to be that much more quiet/stealth
or
you're shooting within 300 ft of a neighboring house
(just don't do it, not worth a federal gun charge)
or
discharging a firearm in city limits etc.
(don't do it)
or
something you really shouldn't do,
unless defending yourself
Fired off a proving caps or snap caps yeah, sort of like a blank,
no projectile leaves the barrel, so you can sort of "dry fire at will"
just to make sure the rounds load & fire, after doing work on them
or practice pulling the trigger etc.
I know that's not what you're looking for, but it's great practice...