Suppressor thoughts

I did a little math based on a 16" 5.56 barrel. All theoretical as the suppressor has not yet been manufactured. Awaiting stamp.

Barrel:
Muzzle pressure: ~7400psi
Barrel volume excluding chamber: .72"

7075 Suppressor tube:
Yield strength: 63000-69000. We’ll use 63000.
Diameter: 2.00"
Wall: .0625

Spacer specs:
Length: 1.5
Inside radius: 1.625
Volume: 3.11"
Spacer wall: .1875

Combined wall thickness: .250
Working pressure of combined material: 10500psi, but we’ll say half of that, because safety.

The interior of the expansion chamber is 4.319 times more volume than the barrel. If muzzle pressure is ~7400psi, the pressure in the expansion chamber will be ~1713.360psi. Well within the theoretical working pressure of the aluminum suppressor.

Edited to add yield strength and edit working pressure of combined material thickness.

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Looks like you have done the math and have a good margin of safety. I’ll sit at the bench beside you and be your spotter any day!

I’m curious about your source for muzzle pressure? I like having multiple sources for cross checking.

Do you load your own ammunition?

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There was a study, EFFECTS OF BARREL LENGTH ON BORE PRESSURE, PROJECTILE VELOCITY and SOUND MEASUREMENT, by Phillip H. Dater M.D. of gemtec and Jason M. Wong of Firearms law group.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2010/armament/WednesdayCumberlandPhilipDater.pdf&ved=2ahUKEwj21JeapsT7AhU5mmoFHeFLB-sQFnoECBcQAQ&usg=AOvVaw27Iz9sEaD4-d8B-LdEhuJj

The pdf was too big to upload here. Basically they marked a 24" barrel at every inch starting 5" from the chamber. Then drilled a 2mm hole every inch and plugged all but the hole at the muzzle. They used a piezoelectric sensor to measure the pressure at the muzzle hole, then cut off at the inch mark, and repeated at every inch.

I don’t reload, but I have reloaded shotgun shells in the past.

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Excellent!!!
Thanks for sharing.

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No worries. Glad to share anything useful that I find :+1:

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To anyone that finds this thread and decides to fabricate the type of item discussed… Please do it the right way. Submit your form 1 and receive approval before starting the manufacturing process. Note: no one in this thread is responsible for any equipment damage, legal repercussions, death, or injury resulting in the use of information on this thread. Thanks,

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What is the projected turn around for the stamp? What are you looking at weight wise on the can?

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As of last month, 29 day turnaround on the stamp. As for the gross weight before any modification of design is ~15oz and some change. Please note that that is an approximation, as the components have not yet been manufactured. That said, I had a conversation with a member of the community that is knowledgeable on the principle of the project, in which he suggested a steel sleeve in the expansion chamber and steel muzzle side cap in substitution of the aluminum material in the current design. I haven’t gotten the raw material for that yet to know an approximate weight, but it will be slightly heavier. When the manufacturing stage starts, I would also have to cut down the original baffle design with a step groove, and step the steel sleeve so they overlap. I haven’t figured out an effective way to do that, so we’ll see if it happens. Disclaimer: Dear ATF, this project has not entered the manufacturing stage, as I am waiting for a stamp. I have raw materials, but no machined parts. Thanks.

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Replacing aluminum with steel probably a good idea. The repeated heat/cool cycles would likely affect the temper of the aluminum, making it brittle.

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