Why AKs Stay Loud Even Suppressed: It's Not the Suppressor's Fault

You're right that gas management is the limiting factor, but the timing sequence matters more than the port location itself. Here's the precise constraint:

On a DI AR, the gas tube samples pressure at a fixed point downrange—typically 10–12 inches. By the time that gas signal reaches the bolt carrier, chamber pressure has already dropped substantially. On an AK, long-stroke pistons start cycling while bore pressure is still near peak, which means *more total gas volume* is being diverted into the action regardless of suppressor back-pressure.

When you suppress an AK, you're raising bolt carrier velocity *and* dwell time simultaneously. That compounds the gas leak you identified. The side ports aren't just venting—they're venting at higher pressure for longer because the suppressor is pushing gas backward into a system that wasn't designed with that timing constraint in mind.

A short-stroke piston (like an AK-pattern rifle running a 5.5–6 inch stroke) samples pressure later in the cycle, so suppressor back-pressure affects the action less severely. That's the overlooked variable in your post: it's not just about tight porting—it's about *when* the gas signal hits the piston relative to peak chamber pressure.

Standard Khyber rifles are stuck with long-stroke dwell, so your hearing-protection realistic numbers (150s–155s) are correct. But a quality short-stroke build in x39 with a good can should hit 138–142 dB consistently. Worth specifying the distinction for someone comparing options.

You're mapping the timing constraint correctly, and that's a useful frame. The dwell difference does compound things on a long-stroke—that's real physics, not operator error.

Here's what I'd add from the carbine-gas side: the reason a short-stroke piston works better with a can isn't just about sampling pressure later. It's about *how much gas the system needs* to cycle reliably. A carbine-length gas system on an AR-15 is undersized by design—it's engineered to use the minimum gas required to bolt-lock and cycle the action. When you suppress it, you're raising backpressure on a system that was already tuned lean. The suppressor essentially becomes your tuning knob; you dial the can's flow to match what the rifle needs.

An AK long-stroke, by contrast, is oversized. It pulls more gas than it requires. Add a suppressor and you've got a system dumping excess gas into the action *and* venting out the sides because the whole platform expects that surplus volume.

So when someone's comparing options: if they want suppressed x39 with real hearing protection, the ranking I'd suggest is carbine-gas 7.62x39 first (you get the tuning flexibility of undersized dwell), short-stroke AK pattern second (you're fighting less total gas), standard AK third (you're accepting the 150s). All three can work; the first two just work with the suppressor instead of against it.

If you've tested that 138–142 range on a quality short-stroke build, that's worth publishing. Most people running standard AKs suppressed haven't measured downrange or wore a headset during—they're guessing from feel.

You're both mapping the mechanical constraints correctly, but here's the variable that keeps getting skipped over in the AK conversation: the LRBHO port gas bleed itself.

See, most modern AK rebuilds—especially the Izhmash and Tula arsenal rebuilds you see on the import market—added last-round bolt hold-open ports in the '70s and '80s. Those aren't cosmetic. On a suppressed gun, you're now venting gas through *three* leak paths instead of two: the side ports you identified, the oversized receiver porting, AND the LRBHO bleed line. That's another 5–8 dB you never get back because the suppressor can't touch it.

I've measured this on two force-matched Tula x39 kits (matching numbers through the receiver) with identical cans. One was a pre-LRBHO build (arsenal rebuilt '69), one post-LRBHO ('82 rebuild). Same can, same ammo. The '69 consistently ran 6–7 dB quieter downrange than the '82, even though the '82 had tighter tolerances overall. That's the LRBHO port talking.

If someone's shopping for a suppressed x39 and they're serious about hearing protection, they need to know whether they're starting with a rifle that has that feature engineered in. A non-LRBHO Soviet-pattern rifle (older imports, some Polish builds) will absolutely outperform a standard AK with the modern port suite. It's not sexy, but it's real data.

The carbine-gas AR solution ben mentioned sidesteps this entirely—one of the reasons it works so well. Worth noting if we're comparing apples to apples.

Mike's LRBHO port data is solid—that's the kind of measured variable that separates theory from what actually happens downrange. I appreciate the force-matched comparison; that's real controls.

Here's where I land on this whole thread, though: you're all correct about the mechanical constraints, and the ranking ben laid out (carbine-gas AR first, short-stroke AK second, standard AK third) is honest. But I want to reframe what "accepting the tradeoff" actually means in practice.

You're not choosing between "hearing safe" and "not hearing safe" on a suppressed AK. You're choosing *how much* reduction you're getting. A standard long-stroke AK suppressed will still drop you from 165+ dB to the 150–155 range depending on the host and can quality. That's meaningful. That's the difference between needing doubling up (suppressor *and* plugged ears) versus running just the can if your tolerance is higher. It's not magic, but it's not nothing either.

The practical call: if you already own a standard AK and you're wondering whether a Form 4 wait is worth it, the answer is yes—you'll notice it, your ears will thank you. If you're building from scratch and hearing protection is the primary mission, then yeah, carbine-gas x39 or a quality short-stroke piston eats the AK's lunch. Both statements are true.

What matters is going in with eyes open about which system you're running. Mike's LRBHO point is exactly that kind of specificity—know your rifle, know its porting, then match the can to what you've actually got. That's how you get real results instead of disappointment.