Here’s a sketch of the internals. Pretty self explanatory.
All but the first baffle single clipped. At 5.5" it’s not exactly a K can, but it’s still shorter than average, and lighter.
So far I’ve only tried it on my Mk18 upper. I need to remove my 6920’s flash hider so I can try it on the 16 inch, which is what my SOT tested it with.
I took a few shots sans ear pro, and it wasn’t exactly pleasant, but also not painful either. But the port pop alone on a 10.3 is way past hearing safe anyways. My SOT went sans ear pro with his 16 inch upper, and he indicated it was hearing safe based on comparing it to a factory can that is a known quantity. Part of that could of course be the tone, so I wouldn’t want to do that very often without good sound metering equipment to back it up.
On my Mk18, I might compare it to maybe shooting a 9mm pistol in terms of discomfort. Part of what makes me think I’m mostly hearing port pop is that I tried it with and without the distal cone (using a longer spacer in the blast chamber), and there was no notable difference, which you would expect there to be. I think once I do the same side by side comparison in both configurations on my 16" upper it’s going to become apparent that there’s a difference. If not I will just lose the distal cone and let the gasses from the coaxial chamber go straight into the distal space. My endcap of choice has some nice stepping, so that should help.
I also need to get out the nods and see what difference it makes for flash. Word on the street is that coaxials somehow reduce flash via some mechanism I’ve yet to grasp. Would be very cool if there was a notable reduction.
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.
It’s a hodgepodge of off the shelf solvent trap parts. That market is getting really good! With a little basic understanding of how silencers work the average person can put together a pretty good can to meet most needs, whether that be pistol, rimfire, or centerfire rifle. I think this style fits the needs of centerfire SBRs extremely well. It’s a good balance between weight, length, suppression, and backpressure mitigation.
The thread adapter and endcap are SPC, the tube is SPC, and the cones are VVT. I got the spacing material off a guy on the form 1 forum.
When I think back to what was state of the art for 1978, the fact that people are now home rolling designs like this, it must be what bi plane fliers felt like watching us go to the moon in 69.
Yea we’ve come a long way from maglites and freeze plugs. Amazing how much innovation people are capable of when the government makes you wait six months to two years for a freaking gun muffler.
So I can remember wipe and mesh technology. I can remember about mid 80s when Doc Dater changed the game for everyone for all time. Now most of that stuff is pretty old hat.
Now that $200 isn’t nearly as cost prohibitive for serious gun guys, suppressors have become “common usage” and that is really driving the tech. By contrast, machine gun tech has gone almost nowhere because private sector advances came to an end in 1986. KAC kicks out an interesting design now and then but there is no across the board revelations other than make it out of polymer and add rails.
Suppressors are not only smaller and more efficient, they are now in many cases user serviceable which was a unicorn dream not very long ago.
I can still remember hanging a sionics can almost as long as the rifle itself on a M-16 and thinking “there has to be a better way.”
I wasn’t able to detect any first round pop, even in the five baffle configuration. Might be because of the coax chamber, I don’t know. Might also become more obvious when I shoot it on the sixteen inch rifle.
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.
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.
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.
