I keep hearing about back pressure and different suppressors having different types. Can someone explain what that means and the advantages of them. I have a sandman s and I am wondering what it is and what are the strengths and weaknesses of these pressure variants

thanks
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I don't consider myself an expert, but own quite a few suppressors. My opinion is that the best thing is to build an AR type rifle with the right size gas port for a suppressor, or use an adjustable gas block / other mechanism to reduce the gas to an appropriate level. Flow thru suppressor designs with very low back pressure tend to be louder in my experience. If you have a non-adjustable piston gun, or refuse to do something to dial the gas down, there are advantages to lower back pressure, otherwise simply adjust for it and don't worry about how much backpressure it has.

For a bolt gun, backpressure doesn't matter.

You'll want an adjustable piston in AR/AK type rifles.

I dont suppress my AR but on my overgassed AK I know:
Adjust the piston till it barely cycles and itll be as quiet as itll ever get with a can.

Somewhat overly simplified but sound is pressure. So suppressors that keep more of the pressure inside are often quieter. The other variable is volume. Larger volume keeps more pressure inside so it can keep the sound down.


There are a few high flow suppressors that are very quiet like HuxWurx but they have a whole other level of wizardry built in.

Can you provide a reference to any data that you have seen, showing they are quieter than an equivalent baffled suppressor on a bolt action rifle? I don't own a HuxWurx, but most of the comparisons I've seen showing improvement over more traditional designs, is at the ear, for untuned ARs. If I see that it is quieter on a bolt action, I might get interested. I can tune an AR to eliminate the excess gas.

This might help some. Looks like a very nice can.
https://pewscience.com/sound-signature-reviews-free/sss-6-113-huxwrx-flow-762-ti-savage-308

Thanks for the reference. I'm surprised how close it is in performance to the Nomad Ti (which I have experience with). They are roughly the same size. The pressure 1.0m left of the muzzle 149.8 db for the Huxwrx vs 147.7 db for the Nomad Ti. For the impulse 133.5 db-ms for the Huxwrx vs 124.6 db-ms for the Nomad Ti. The Nomad Ti is still quieter, but not by much. I like the Nomad series, but wouldn't recommend them to anyone right now due to Dead Air's inability to turn around their warranty repairs.

I was looking at the Nomad series a good while back but never pulled the trigger on one. I've been looking at Diligent Defense Enticer cans now. On Pew Science that are rated extremely well and priced really good.

So when guys are talking about high back pressure cans they arent talking about a particular can? They are talking about the gas adjustment and how much it is gassed or not gassed from the rifle??? It has nothing to do with the can itself?? My long stroke piston AR has 3 levels of gas adjustment. So is my can (Dead Air Sandman S) a high backpressure can depending on where i adjust my gas???

No some cans are definitely gassy. I’m running a YHM resonator which has extremely high back pressure but it is also one of the quieter 30 cal cans on the market. On semi autos they run nasty dirty but being able to shoot comfortably on my .308 bolt makes it all worth it.


You running a compact can which will have lower pressure and lower volume making for an extremely loud can.

Buy a Nomad L if you want sound performance.

Different suppressors have different amounts of back pressure. Higher back pressure at the muzzle, forces more gas through the barrel port that drives the action. That increased gas speeds up your BCG, and may cause cycling issues. It can also result in more gas in your face, and more noise through the ejection port. Higher back pressure cans need more constriction to reduce the gas flow that is driving the action than lower back pressure cans. If you get the firearm adjusted properly (meaning the gas driving the action is reduced to what is needed for reliable cycling) you don't have an issue. Ideally, a suppressor would make a firearm perfectly silent, do nothing to change the point of aim, and add no backpressure. Unfortunately, that isn't possible, and there are tradeoffs. Does that help?

Now I understand a little more. Thank you guys. Basically the smaller the can the higher the backpressure. My 6 inch can (sandman S) is considered a high backpressure can because it is only 6 inches long and doesnt have a lot of volume to absorb and disperse the backpressure inside. Appreciate the knowledge.