KAC QDC Suppressors Finally Hitting Stores

[Sensei]

I was getting ready to drop some coin on a SilencerCo Saker 762 and 556K. However, the KAC QDC line of suppressors are starting to finally hit the shelves; KAC has been catching up with agency orders for 2 years. Unfortunately, there is not much out there on the new KAC in terms of independent testing.

I need 2 suppressors for my 10.5" SBRs which are my home defense and vehicle guns. I will also need the 762 for my MWS and SCAR-17 which are set up for ranges between 50-500 meters. If I go the Saker route, the 762 would serve double duty as a 556 can and save me from having to buy a dedicated 762 suppressor since KAC uses caliber-specific mounting platforms. Because I'm using the 556 cans for home defense, I want to know if the KAC QDC full-size is hitting more than 144 dB. I'll probably put the 556 QDC/CQB can on the SBR that rides in my vehicle - it does not get shot indoors so I just want it to take the tooth rattle out of the 556 SBR shot. I do not care too much about dB rating for the 762 guns since they are outdoor medium range guns.

Both the Saker Trifecta MAAD and KAC QDC mounts seem solid on paper. However, I watched a Trifecta get stuck on a barrel a few months ago. I have no personal experience with the KAC QDC.

The POI for both KAC and Saker is reported to be minimal and consistent. The Saker at the range shifted very little to the right after we put it on; I've never seen a KAC to comment, but the few internet reports seem reasonable.

Size and weight is virtually identical between the Saker and KAC QDC lines except for the uber small KAC CQB. Both 556 models are about 6.5" and 18 oz. and the 762's are 7.5" and within 1 oz of each other near the 20 oz mark. While I've never dissected a KAC suppressor, I trust that both are built to high standards.

The big question is how does KAC do in terms of suppression and gas blow back? SF has a reputation of being a tight lock-up (if you do it correctly) and little POI shift, but about 5-10 dB louder than the Saker or Omega. This is significant and very noticeable to anyone who has shot a Saker and SF SOCOM next to each othe because it is really crossing that 140 dB threshold that makes my ears ring. Is the KAC QDC also a good bit louder than the SilencerCo offerings? While I'm not interested in chasing a couple of decibels of performance below 140, more than 5 or 6 is very significant to hearing damage when you cross that 140 dB threshold indoors.

I've considered other offerings from Rugged, Thunderbeast, et al and found them lacking for my uses.

[Unobtanium]

There really is no 140dB threshold, physiologically speaking. That's a random number OSHA pulled out of their ass, because they needed a hard number for legal purposes. Also, you're going to want to compare ejection port signatures, as well. For example, the SPR-M4 from AAC is louder to the shooter than the MINI-4.

[Sensei]

Another issue is that I can't seem to find minimum barrel lengths for the 556 QDC suppressors. A thread on ARF mentions them being tested down to 11.5" but I find this a bit surprising given the numbers of MK18's floating around SOCOM.

[LittleLebowski]

Before I jump in with unrelated suggestions on what I would buy, what attracts you to KAC and is price an issue?

[BWT]

There really is no 140dB threshold, physiologically speaking. That's a random number OSHA pulled out of their ass, because they needed a hard number for legal purposes. Also, you're going to want to compare ejection port signatures, as well. For example, the SPR-M4 from AAC is louder to the shooter than the MINI-4.

dB's dissipate based on the source of the sound and the distance from the source.

Standard military metering is 1 Meter from the muzzle and so many inches in height as the baseline.

When I did testing over a weekend years ago with nfatalk; they used two B&K 2209's with appropriate microphones to meter that aforementioned location and the location near the shooter's ear.

Our military measuring technique catches a data point at a standardized distance/configuration to gain better impressions than "it seemed quieter" or "my ears rang".

It captures an impulse level; is it perfect? No, but it's fairly decent. I found my ears rang with most guns near 128 dB. But my ear canal was a factor, the terrain was a factor, the temperature, host, air density, etc, etc, etc.

ETA: Short of a room full of microphones (that would also reflect sound and complicate the acoustics of the test); this is the best way to deal with this situation.

Personally, I'd go with a 30 Cal Fast Attach can to deal because of more volume which results in less back pressure typically in .223 and can be used on both hosts.

[Sensei]

Before I jump in with unrelated suggestions on what I would buy, what attracts you to KAC and is price an issue?

First, I like the mount and love the MAMS brake for 16" 308s (although it's expensive and hard to find at times).

Second, the size and weight are very competitive. The QDC is right there with the Saker at 6.7" and 18 oz, and the QDC/CQB seems like a really neat little suppressor at only 4.7". Granted it's nowhere near hearing safe, but it can at least take the edge off indoor rifle shots. There is an amature video on YouTube comparing the 556 QDC/CQB to a M4 2000 and the difference was very slight.

I'm never going to say that price is immaterial, but we are talking about a $350 difference in a lifetime investment.

Last and definitely least - I'm a bit of a KAC fanboy. I've come to accept that at night when I do my daily affirmations in front of the mirror.

[LittleLebowski]

First, I like the mount and love the MAMS brake for 16" 308s (although it's expensive and hard to find at times).

Second, the size and weight are very competitive. The QDC is right there with the Saker at 6.7" and 18 oz, and the QDC/CQB seems like a really neat little suppressor at only 4.7". Granted it's nowhere near hearing safe, but it can at least take the edge off indoor rifle shots. There is an amature video on YouTube comparing the 556 QDC/CQB to a M4 2000 and the difference was very slight.

I'm never going to say that price is immaterial, but we are talking about a $350 difference in a lifetime investment.

Last and definitely least - I'm a bit of a KAC fanboy. I've come to accept that at night when I do my daily affirmations in front of the mirror.

Works for me. Let me page a guy I know.....

[Sensei]

Update: I spoke with several people at KAC about the minimum barrel length for their cans. Although they have not tested the 556 suppressors down to 10 inches, they feel that the blast baffle is strong enough for this length and there should be no problems.

Another person outside of KAC with knowledge of several QDC 556 cans on agency Mk18's said that those cans are running fine despite high round counts of dedicated suppressed fire.

[StraitR]

My biggest hangup with KAC suppressors is that the 7.62 models will not fit on 5.56 muzzle devices, eliminating the crossover game. I'm a big KAC fan, love my Mod 2, and have their kit splattered all over my other rifles, but I won't spend over $3k on cans/stamps to achieve the same thing that I can do with $1k on a single .30cal can. I really wanted a 7.62 QDC CQB, but I went with the Omega for the aforementioned reason.

[LittleLebowski]

My biggest hangup with KAC suppressors is that the 7.62 models will not fit on 5.56 muzzle devices, eliminating the crossover game. I'm a big KAC fan, love my Mod 2, and have their kit splattered all over my other rifles, but I won't spend over $3k on cans/stamps to achieve the same thing that I can do with $1k on a single .30cal can. I really wanted a 7.62 QDC CQB, but I went with the Omega for the aforementioned reason.

Wow. I wasn't aware of that. I concur.