Integral Suppressed Sten, Blast Chamber Question

[Kujo]

I am in the early stages of an integral suppressed Sten design and I’m wondering what the implications of a blast chamber are when I have a heavily ported barrel to drop the velocities into the subsonic ranges. Will these ports allowing gas into about an 8 inch expansion chamber eliminate the need for a blast chamber, or atleast allow the use of a much smaller chamber to prevent erosion of the first baffle.
Also, if I’m using available 60 degree cones, would i get away with running Two or three titanium baffles followed by aluminum? Everything I’ve read doesn’t recommend aluminum for anything other than .22, but the weight savings and price would be nice.

[#40Fan]

Did you forget that you had already started a post?

viewtopic.php?f=10&t=156217

[Kujo]

I’m sorry it was a different question and I was not getting any replies on the last post. I’m not sure how a “bump” system works in this forum just yet and wasn’t sure if the post would get lost.

[ECCO Machine]

You don't really need any "blast chamber" with low pressure, low gas volume cartridges like 9mm. Incorporating one actually tends to work against the goal of suppression, increases first round pop.

Also, if I’m using available 60 degree cones, would i get away with running Two or three titanium baffles followed by aluminum? Everything I’ve read doesn’t recommend aluminum for anything other than .22, but the weight savings and price would be nice.

Nothing wrong with aluminum in pistol caliber cans, as long as they're not being abused on full auto SMGs. That said, choose a proper alloy, and it's definitely best to anodize so that the material won't be corroded by oxidation or especially galvanic corrosion if using more noble tube materials like SS and Ti.

The first two baffles in my Phoenix XLV, Phoenix M and Phoenix IX models are 17-4 H900 stainless, the remainder are anodized 7075-T651. I also use 7075 for baffles #3-9 in my Phantom 8 lightweight rifle can.

The high strength, high hardness aerospace aluminum alloys like 7075-T651 & 7068-T6511 are more than adequate for use in suppressors, you just have to be mindful of temperatures, as they weaken significantly above 350°F. That's why no machine gun use, and very slow rates of fire when used in high velocity rifle suppressors.

[Kujo]

Thanks a lot ECCO Machine! That answers all of my questions. The aluminum should work just fine for my purposes then, I don’t plan on doing mag dumps back to back or anything.
By the way, I believe I’m subscribed to you on YouTube? I love your work.

[pmercer]

If you search my posts, I started a thread on an original silenced sterling (very similar to sten) It’s very picture heavy. You may find it of use.

viewtopic.php?f=5&t=11489&p=951803#p951803