My new Form 1 build

[Clint]

You may want to try moving the unported "transfer" baffle to position #4.
The theory being more disruptive mixing early in the stack and a little less direct path out for the bypass flow.

I can also move that unported cone anywhere in the stack, so I might try different positions and see what effect it has on backpressure.

Please do.

[okie]

You may want to try moving the unported "transfer" baffle to position #4.
The theory being more disruptive mixing early in the stack and a little less direct path out for the bypass flow.

Definitely plan on trying different positions. Funny thing though...

I actually had my SOT cut two blast chamber spacers. The one you see in the drawing, and a longer one that lets me run the can without the unvented baffle. So the unvented baffle at the end is removed completely, and the other baffles move up.

I wanted to see what the difference was between letting the gas recombine vs. just letting it vent directly into the distal chamber.

I've already tried both configurations, and I couldn't tell any difference whatsoever. I wish I had a good sound meter though. I would be very interested to know if there's any measurable difference.

But it's got me wondering if it simply doesn't make any difference where the coaxial chamber vents to. The gas is going to come out the end one way or another. I think by keeping pressure in the coaxial chamber low it encourages gas to leave the laminar column and go around. Because once the can reaches equilibrium, the laminar column will just go straight through. By keeping the resistance in the coaxial chamber lower, you're always ensuring that the path of least resistance is not the one straight out the bore.

[markm]

I've never found suppressors to sound much different at all. The only can, out of a dozen or so that we run regularly, that sounds noticeably different is the 762Sdn on the 308 bolt gun. That sucker is louder.

When we did an F1 kit, the thing I did, which didn't pan out, was leave a roomy blast chamber. Cutting metal without good machine shop resources is exhausting. So you talk yourself into the idea that 5 baffles is enough. But as I posted before, I had to go back in and add a baffle and some clips to the existing baffles.

[Clint]

It's really hard to predict what will happen due to the complex dynamics at play.

It's anybody's guess and it comes down to testing to find out.


One reason there may not be a perceptible difference between the two configurations, is the port pop may be dominating the at ear sound levels.

With an unmodified gas system, the sound levels from from the gas piston venting can easily be 140-150 dB at the ear, completely masking the 130-140 dB at the muzzle.

Once the gas is dialed down, it may be easier to detect differences.

I've already tried both configurations, and I couldn't tell any difference whatsoever. I wish I had a good sound meter though. I would be very interested to know if there's any measurable difference.

But it's got me wondering if it simply doesn't make any difference where the coaxial chamber vents to. The gas is going to come out the end one way or another. I think by keeping pressure in the coaxial chamber low it encourages gas to leave the laminar column and go around. Because once the can reaches equilibrium, the laminar column will just go straight through. By keeping the resistance in the coaxial chamber lower, you're always ensuring that the path of least resistance is not the one straight out the bore.

[okie]

I've never found suppressors to sound much different at all. The only can, out of a dozen or so that we run regularly, that sounds noticeably different is the 762Sdn on the 308 bolt gun. That sucker is louder.

When we did an F1 kit, the thing I did, which didn't pan out, was leave a roomy blast chamber. Cutting metal without good machine shop resources is exhausting. So you talk yourself into the idea that 5 baffles is enough. But as I posted before, I had to go back in and add a baffle and some clips to the existing baffles.

A silencer without clips is basically a big heavy expensive muzzle brake.

[okie]

It's really hard to predict what will happen due to the complex dynamics at play.

It's anybody's guess and it comes down to testing to find out.


One reason there may not be a perceptible difference between the two configurations, is the port pop may be dominating the at ear sound levels.

With an unmodified gas system, the sound levels from from the gas piston venting can easily be 140-150 dB at the ear, completely masking the 130-140 dB at the muzzle.

Once the gas is dialed down, it may be easier to detect differences.

That's what I'm wondering, too. Just need to get off my but and remove the flash hider on my 16 inch so I can give that a try.

[hi-wayman]

it would be interesting to run the tests on a bolt gun or shut off the gas completely. No port pop at all.

[okie]

it would be interesting to run the tests on a bolt gun or shut off the gas completely. No port pop at all.

That's the proper way. Should probably get a 223 bolt gun since apparently this is my new obsession now.

[Clint]

NFA enhanced BRD...

That's the proper way. Should probably get a 223 bolt gun since apparently this is my new obsession now.

[okie]

NFA enhanced BRD...

Oof. Why couldn't I have been born in New York where they don't have to worry about such things.