I’m reaching information overload level, so decided to just come ask the experts. I just put a 9mm can in jail, and want to get a new host.

I bought a TNW Aero Survival Pistol just before braces became NFA. But since then I have been reading about how direct blowback hosts are still very loud suppressed. I can’t afford an MP5, and probably wouldn’t spend $2,000 for a Sig MPX either. I haven’t really seen much talk about Kriss platforms, but I would spring the extra $ for one of those if they are close to “Hollywood quiet”.

As far as I can tell, that leaves the Stribog A3 versus the AP5. I’m here to ask if there are other options I should consider as well as which of those 2 is quieter. I have read plenty of accounts of people preferring the AP5, but not really for reasons that matter to me.

TIA

I had an MPX and hated it.  Gassy and LOUD.

MP5 is a proven classic and now is a great time to get  an AP5 at a great price.
However trigger isn't all that great nor the ergonomics.  No LRBHO if you care about that.

Don't know much about the Stribog other than seeing one at a match and he had to send it back to get it running.  Heard the same thing from others.  Not sure if all the bugs are worked out yet.

There is the upcoming MEAN Arms bearing delay upper that is supposed to be shipping Q1 or early Q2.  I am on the list for one of those but the complete uppers are starting around 1400.

There is also the CMMG RDB.  The only thing proprietary is the BCG and Barrel which start a little under 400.  So if you have some spare AR parts you can put one together for cheap and they are tunable. I have also run them using a 5.45 bolt to make it a bolt action single shot.  You can't get quiter than that as there is no action noise.

If you aren't running subs or a ported barrel...it doesn't really matter...

Yea the average trigger and no LRBHO are the main drawbacks I have heard about, neither particularly matter to me.

I just want a quiet and fun range toy. I guess I forgot to add this part, would any of them (including the CMMG upper) be better suited to shooting 158 and/or 165 grain bullets?

Just do Google search for MP5 and 158Gr and read: https://www.google.com/search?q=mp5+and+158+grain
I was always told no by people I know but you can read in there mixed information.

I think it is because there are so many various loads out there.

Look at 147Gr.... some is loaded super hot to even be supersonic out of handguns and most are not.
I believe Fiocchi has at least two different 147 loads one being much hotter than the other.

I've had some people tell me the old IMI 158 Gr Blue Tip was so hot that it would come out of the UZI with the brass being buldged.  
I had a friend give me some 1980's production IMI 158 Gr Blue Tip and ran it out of one my open bolt UZI SMG's and it averaged 934 fps out of a 3 lugged IMI barrel and I saw no signs of overpressure.

So maybe I had a weak lot or IMI had complaints of it being to hot and toned it down some?  Who knows.

Bottom line is I think if you read the Google results some people have had issues while some have not and I think that all comes down to how the 158 Gr was loaded.
BTW, I did test some Fiocchi 158 Gr and find it to be weak compared to the IMI 158 Gr.  Impulse felt lower and it averaged 877 fps out of the same UZI SMG.

All that said, I don't think you will have any issues running any loads out of the CMMG RDB.

I have run a few 158Gr and didn't notice any issues but I reload and 147's are way more common so I just standardize on that.
My website that has a lot of CMMG RDB information: https://c3junkie.com/?page_id=164

I am actually running a .40SW CMMG bolt for use in 9mm to further delay the action.

Don't you have to match the angles in the extension?  Did you swap that too?

While their patent does mention angles on the extension, it isn't actually done that way.  
I have this documented on my site: https://c3junkie.com/?page_id=280

I did end up buying a CMMG bolt/barrel - will have to tune into your website.

Thanks for all the responses, I might buy an AP5 down the road as well.

My GHM9 is pretty quiet with a yhm N2O.

What can did you buy??? That can be a huge difference.

Interesting,  I may have to get a .40 bolt too.

ECCO Machine 7.5” TL (1.3 diameter)

Please be sure to read my link above....since I have a custom barrel that has been headspaced to the .40SW bolt and also with all the slop that seems inherent in the CMMG RDB design.  It will not function with the factory spring loaded ejector.  Fortunately for me, I am running a custom fixed ejector in the upper.
As mentioned on my site, I believe that the headspace slop in the CMMG RDB design was done on purpose as it seems that if the slop is removed it doesn't have a needed impulse to cycle and they didn't want to bother with a fixed ejector.  Which is kind of ironic as their latest 'Dissent' bufferless option uses the RDB design for 9mm and they went to a fixed ejector in that design.

I have a local friend with a CMMG RDB in 9mm and he tried a .40SW bolt in his and it wouldn't work for him.  However, I have had other people reach out to me stated it did work.

Again, IMHO, this all comes down to how the barrels are headspaced.  They are trying to headspace an angled surface on their bolt lugs to an unmodified squared off extension.  I think some people have excessive headspacing like documented at my site here: https://c3junkie.com/?page_id=221

My original 9mm CMMG RDB barrel had a standard M4 extension with dual feed ramps even though they only had the Glock mag option at the time and the MEAN Arms Endomags didn't exist yet.  That barrel had extremely excessive headspacing and was eating parts (extractors, cam pins, FP's etc).
I later figured that out and made the video you can see on my site and they swapped my barrel with one that doesn't exhibit the same issues of being able to extract a case with no suppressor mounted the extractor removed (video on my site).

I think it is hit or miss

This is false.

My personal experience with suppressed 9mm PCC/SMG’s is with the following;

MP5
CZ Scorpion
Uzi (closed bolt)
Kalashnikov USA KP9
10.5” 9mm AR

Of all of them, the quietest was the MP5 and it’s roller delayed action. With a wet can and 147 grain subsonics, all you hear is action noise and rounds impacting down range. The next closest would be the Uzi with the heavy bolt.

The other three were definitely louder.

Scorpion, couple of AP5s and A3 Stribog, ( now with a Lingle lower ).
My suppressor is an Osprey 45, not a dedicated 9, but still pretty decent.

Scorpion is louder, esp from the port.
I can't tell a difference between the Stribog and AP5s.

Roller delay master race. Hard to beat the HK SP5.
More quiet then my CZ scorpion with the same cans

I agree with this guy, though I'd place the Banshee right below the MP-5. It's a toss up between it and the Scorpion for who is quieter.  Don't own an Uzi, but do have a KP-9 and it is also very quiet.

Went shooting for a few hours yesterday sighting in some optics. Took an AP5-P, PC Charger, Scorpion EVO-3, and Banshee. All were running suppressed with YHM R9 cans. Ran a variety of ammo. Mainly my 147 gr subsonic handloads, 124 gr handload supers, but also S&B 124 gr, and Federal Syntech 124 gr and 150 gr.

AP5 is darn near Hollywood quiet and arguably my favorite. I'm a Lefty, so not too fond of lots of gas to the face. Don't really get any gas out of my handloads or most factory ammo, but surprisingly got a lot out of the 124 gr Federal Syntech which were supersonic. The 150 gr Syntech subs were much quieter and very little gas.

The PC Charger is growing on me but seems to be the loudest at my ear with that huge weighted bolt slamming around. The Banshee is a joy to shoot and I've never had the slightest trouble with it.  You can definitely feel how it is smoother and less jarring due to RDB.  

Ironically, I have a tube of lube but keep forgetting to try it out. I even put the lube in the suppressor bag and still forgot to try it yesterday.  From videos I've seen, it makes a significant difference, especially on fat cans like the R9.

I need to get a good MP5SD video, because it’s the quietest, but here is CZ Scorpion EVO with B&T 3-lug suppressor with 124 gr rounds vs MP5 with Dead Air Wolfman with subsonic rounds.  Unfortunately, not a fair comparison.

MP5 by a mile. Stupid quiet with subs and it’s the OG.

If you will only own one, it has to be an mp5. Mine has different styles sometimes:

MP5 (or AP5) and a large volume can is going to be hard to beat. In fact, short of a bolt action that's about as good as it gets.  The UZI and STEN are also unusually quiet, but I'm not sure if the concept translates to closed bolt examples.

Since the MP5 is winning the vote so far, does anyone have a direct comparison to the scorpion with the IA-SC9?  That one seems pretty quiet, overall.

Probably the quietest 9 available today.  


https://pof-usa.com/firearm/tombstone-9mm/

I have been actively avoiding the local shop that has one of these in stock.

Quietest I have by a longshot is a MP5 with 165gr reloads using 2.6gr of Titegroup. Sounds like a staple gun.  

It's almost equally quiet in my CMMG rdb upper, but it won't run reliably in it. I'm going to have to try lighter springs and buffers.

Quietest sure ... but dang ... for that money I'd rock a MP5/B&T/CZ ... those have some teething issues right now with quality ... so just be aware ...

Dont count out colt 9mm carbine.  I have shot literally all the mainstream 9mm PCCs and own several MP5s.  For whatever reason, that colt carbine sounds every bit as quiet as my MP5s (current king as 9mm suppressor host in my opinion).

My unscientific hypothesis on why that colt 9mm carbine is very quiet for a direct blowback gun is that it has an ejection port shield that sends the sound forward vs back at you.  

Colt AR6951 is the model Im referring to….

I did end up buying an AP5-P instead.

My MP5 clones are pretty quiet when suppressed.  One in particular is really quiet.  Here's a few of my PCC's...

Nice!