Suppressor recommendations for B&T APC223 Gen 2 SBR

[paco ramirez]

How do 17-4, inconel(whatever type is typical for baffles) stellite, and c300 stack up for high-temp erosion?

I have (probably erroneously) assumed the Ni-Co alloys were very close at the top, with 17-4 in 2nd place. Ive seen in marketed (17-4) as a balance of durability and price, which I read as not as good... but will likely last a lifetime on a semi with normal use.

Ti, im assuming is a distant 3rd (light use/hunting), and aluminum is unacceptable for rifles.

Looking for someone with experience/knowledge to confirm/correct.

It depends on what it's being judged by but for the most part 718 Inconel is the king of silencer materials for its properties during hard use and high heat. Higher temperatures are where 718 Inconel and Stellite 6 excel. 718 Inconel being better than Stellite 6 because it isn't brittle, is stronger at higher temperatures, has good corrosion resistance at those higher temperatures, and has far more manufacturing capabilities. Stellite is very abrasion resistant but is limited to casting because machining it sucks hard which can lead to porosity in the casting sometimes. C300 maraging steel, while it has a high yield strength at lower temperatures, would take third or fourth place behind those depending on how important corrosion resistance is because it's really bad at that, and the yield strength drops off significantly at 1000 deg F. C300 can basically be viewed as an alternate material option where 17-4 is commonly used, but that's if the lack of C300's corrosion resistance doesn't matter. 17-4 H900 is much better at corrosion resistance to around 600 deg F, and has decent yield strength to around 800-1000 deg. Grade 5 Titanium shouldn't be used past 800 deg F as it because far more susceptible to corrosion and particle erosion. 7075 T6 aluminum is just fine for some applications in rifle silencers, usually limited to low volume firing on bolt guns or very light semi auto use as a lower cost silencer option. Grade 5 titanium tends to be a better choice for this but is obviously much more expensive.

Besides material, we've learned in the last few years that erosion resistance depends on the design of the silencer system overall, beyond just putting extra material on the mouth of the blast baffle which just takes a bit longer to erode away as opposed to eliminating or limiting it in the first place. Our patented Hyperion Technology utilized in all of our rifle silencer is currently the only tech that can eliminate, or at the very least significantly limit, particle erosion even on 5.5" 5.56mm. Our Grade 5 titanium silencer after 12,800rds of 260 Remington on an 18" semi auto host didn't have any erosion despite the blast baffle being only ~.7" in front of the actual muzzle. That can be compared to another company's Grade 5 Titanium silencer that had severe erosion after only 5000rds of Blackout. However, flash hider jet cutting can still occur depending on who's flash hider is being used. But I have a very simple fix for that too.

[hotrodder636]

Thanks for the info Josh. I really enjoy reading about the various alloys and what makes them good choices for suppressor baffle design.
It is ironic, in my industry (nuclear power) we have been using these alloys for decades due to their temperature properties in high heat environments. The question I have is how much “better” does the 718 perform over Stellite? Marginally or significantly as in factor of 3x or more?

Lastly, for quick clarification, your CGS cans are threaded to accept the KeyMo adapters, correct?

It depends on what it's being judged by but for the most part 718 Inconel is the king of silencer materials for its properties during hard use and high heat. Higher temperatures are where 718 Inconel and Stellite 6 excel. 718 Inconel being better than Stellite 6 because it isn't brittle, is stronger at higher temperatures, has good corrosion resistance at those higher temperatures, and has far more manufacturing capabilities. Stellite is very abrasion resistant but is limited to casting because machining it sucks hard which can lead to porosity in the casting sometimes. C300 maraging steel, while it has a high yield strength at lower temperatures, would take third or fourth place behind those depending on how important corrosion resistance is because it's really bad at that, and the yield strength drops off significantly at 1000 deg F. C300 can basically be viewed as an alternate material option where 17-4 is commonly used, but that's if the lack of C300's corrosion resistance doesn't matter. 17-4 H900 is much better at corrosion resistance to around 600 deg F, and has decent yield strength to around 800-1000 deg. Grade 5 Titanium shouldn't be used past 800 deg F as it because far more susceptible to corrosion and particle erosion. 7075 T6 aluminum is just fine for some applications in rifle silencers, usually limited to low volume firing on bolt guns or very light semi auto use as a lower cost silencer option. Grade 5 titanium tends to be a better choice for this but is obviously much more expensive.

Besides material, we've learned in the last few years that erosion resistance depends on the design of the silencer system overall, beyond just putting extra material on the mouth of the blast baffle which just takes a bit longer to erode away as opposed to eliminating or limiting it in the first place. Our patented Hyperion Technology utilized in all of our rifle silencer is currently the only tech that can eliminate, or at the very least significantly limit, particle erosion even on 5.5" 5.56mm. Our Grade 5 titanium silencer after 12,800rds of 260 Remington on an 18" semi auto host didn't have any erosion despite the blast baffle being only ~.7" in front of the actual muzzle. That can be compared to another company's Grade 5 Titanium silencer that had severe erosion after only 5000rds of Blackout. However, flash hider jet cutting can still occur depending on who's flash hider is being used. But I have a very simple fix for that too.

[paco ramirez]

Thanks for the info Josh. I really enjoy reading about the various alloys and what makes them good choices for suppressor baffle design.
It is ironic, in my industry (nuclear power) we have been using these alloys for decades due to their temperature properties in high heat environments. The question I have is how much “better” does the 718 perform over Stellite? Marginally or significantly as in factor of 3x or more?

Lastly, for quick clarification, your CGS cans are threaded to accept the KeyMo adapters, correct?

I'll have to find the info in a few hours on that so I can show you the minimum required values for aerospace and the typical achievable yield strengths that are normally gotten after a proper heat treat. But due to Stellite's manufacturing limitations, 718 Inconel would always be the better choice because casting has downsides like the potential for porosity that I mentioned and geometry limitations due to the manufacturing process. That porosity issue has shown up in some Dead Air baffle unfortunately, but they obviously remedied that. They're great people over there. Many people don't realize it, but even the DMLS process we use has geometry limitations, it's just a different set of limitations with a far more narrow scope. People think "3D printing" and believe any shape can be made, but that's just not how it works in a silencer at least.

Currently the only silencer we offer with 1.375x24 Omega Pattern compatibility is the Helios QD I've been talking about.

Stellite casting porosity, could also be a chip from a bullet impact but that's unlikely as it's the blast baffle at 1500rds:


Stellite casting porosity, could also be the other unlikely possibility, this one at 3000rds:


Stellite is extremely hard, but due to it's brittleness if a bullet impacts Stellite it's likely to chip off material. Could be a bullet impact in the pics above, it's just unlikely. They're two different silencers.

On this Omega you can see how off center the cast Stellite is from the EDMed bore hole.

[MegademiC]

It depends on what it's being judged by but for the most part 718 Inconel is the king of silencer materials for its properties during hard use and high heat. Higher temperatures are where 718 Inconel and Stellite 6 excel. 718 Inconel being better than Stellite 6 because it isn't brittle, is stronger at higher temperatures, has good corrosion resistance at those higher temperatures, and has far more manufacturing capabilities. Stellite is very abrasion resistant but is limited to casting because machining it sucks hard which can lead to porosity in the casting sometimes. C300 maraging steel, while it has a high yield strength at lower temperatures, would take third or fourth place behind those depending on how important corrosion resistance is because it's really bad at that, and the yield strength drops off significantly at 1000 deg F. C300 can basically be viewed as an alternate material option where 17-4 is commonly used, but that's if the lack of C300's corrosion resistance doesn't matter. 17-4 H900 is much better at corrosion resistance to around 600 deg F, and has decent yield strength to around 800-1000 deg. Grade 5 Titanium shouldn't be used past 800 deg F as it because far more susceptible to corrosion and particle erosion. 7075 T6 aluminum is just fine for some applications in rifle silencers, usually limited to low volume firing on bolt guns or very light semi auto use as a lower cost silencer option. Grade 5 titanium tends to be a better choice for this but is obviously much more expensive.

Besides material, we've learned in the last few years that erosion resistance depends on the design of the silencer system overall, beyond just putting extra material on the mouth of the blast baffle which just takes a bit longer to erode away as opposed to eliminating or limiting it in the first place. Our patented Hyperion Technology utilized in all of our rifle silencer is currently the only tech that can eliminate, or at the very least significantly limit, particle erosion even on 5.5" 5.56mm. Our Grade 5 titanium silencer after 12,800rds of 260 Remington on an 18" semi auto host didn't have any erosion despite the blast baffle being only ~.7" in front of the actual muzzle. That can be compared to another company's Grade 5 Titanium silencer that had severe erosion after only 5000rds of Blackout. However, flash hider jet cutting can still occur depending on who's flash hider is being used. But I have a very simple fix for that too.

Wow, very interesting... thanks.