I tried shooting some subsonic PPU FMJ BT 182g 11,8 g yesterday and it was quite but did not spit the casing.
I then shot some Hornady subsonic 255 g SUB-X this was much better, it spit the casing out but did not cycle the next round.
Im guessing I need an adjustable gas block to get this to function repeatedly any recommendations?
Either an adjustable.gas block or a can. What buffer/spring are you using?
Adjustable gas block is almost a necessity. Also, the amount of increased back pressure from the can is a variable as well.
I would do some homework on the round you’re using. Some subsonic rounds require a faster barrel twist for round stabilization than what the KS-47 offers. If your round is still wobbling when it enters the can, there’s the potential for a baffle strike.
Wait - did you have the can On when shooting the subs, and Failure to Feed? If no, then that’s likely the problem. Just not enough Oompa-Loompah from the cartridge.
Adjustable gas block Restricts gas coming from the barrel port. If you don’t have enough gas going through [without one], a further restriction will not help you.
I have the can on.
I bought the subsonic ammo to see how quiet it was going to run and bought the 2 different manufacturers of ammunition to see the difference in how they sounded and performed only then to find that I have an issue if I want to shoot this suppressed because neither cycle.
(I may have missed this) Have you done anything to it, like put a heavy AR10 Carbine spring in it?
Does it cycle properly with Supers? With and without the can?
I’m not expert at this, by any means. A Student of the Silence myself. Just trying to ask educated-enough question(s) that it jostles the answer out of someone who maybe DOES know.
You know I sure didn’t try it without the can… 
I don’t know the answer to that and the buffer spring is stock for the Ks 47 I just added a different brake compatible for my can. Standard Ak range rounds run fantastic and accurate. I just have a can that works for this caliber and decided to give it a go because I love this ks47 it’s fun to shoot.
Although this would be an irregularity: it almost sounds like the rifle is a little undergassed from the factory.
Usually there’s a (relatively!) huge gas port, and shooting with a can DOES require an adjustable gas block, because of increased port-pressure from said-same can: a restriction to keep the bolt from smacking the buffer into the end of the tube like a sledgehammer and spitting gas in your face like you insulted its mama.
IF that turns out to be the case, embiggening the port slightly, AND an adjustable gas block to tune between shooting subs and supers, with and without the can, MAY be the Answer.
That is literally the Last thing to do, when you’ve determined nothing else will work.
I know that talking to PSA CS will quite possibly be limited help here. But you really should call them, and see what they say. I’m going to try not putting words in their mouth, but they will possibly say to just not shoot subs. OR, they may tell you to box it up and send it in, and they perform a Port-Embiggenectomy.
I’ll throw this out there as well. The 10.5” is obnoxiously (but not ear-ringing) loud outdoors even with a can when using non-subs for ammo. My 16” upper makes it sound like a .22 and, when outdoors, isn’t unpleasant at all. Keep in mind, though, that you’re sacrificing a ton of velocity shooting subs. Not only do you radically decrease your effective range, but your optic reticle/hold overs go out the window as well. If you’re suppressing to make it hearing safe for home defense, you may be forced to choose between the added volume of non-sub ammo through your can, or the decreased reliability shooting a weapon that now lacks the butt to cycle your next round in.
