Thread: Subsonic 300BLK Noise levels

My ODL 300BLK can was tight on the first 20- 30 times using it and now it has settled in nice on the barrel tread.

Cool that sounds a bit like what I'm experiencing then. I'll tell you what though ODL has some amazing customer service... can't say enough good things

Just getting around to this thread thanks to Res for the mention, although I am not sure how that works. Is it the hash tag?

Thanks for the purchase Clavulante. Originally we had several complaints of too loose of thread so we made them tighter and I stopped cleaning up the thread a second time after heat treat. Each can is tested for thread function with a bar turned to the "average barrel" diameter and thread. I suspect that the ones that are tight have a close fit at the barrel overlap. As long as the thread doesn't pick up a burr on the barrel, a tight fit is good.

Regarding the bolt adjustment. I think this is a great idea and am looking forward to trying it out. As Res pointed out, the gas has to go somewhere so what difference does the bolt adjust make. The gas will still vent from the tube but the sound reduction comes from the bolt staying closed longer. If the bolt opens too soon, gas still under pressure in the can will vent both forward and backward out the bolt and right into your ear.

A few other comments on sound testing. If a phone app or sound meter goes up to 140 dB why won't it work for suppressed gunshots? This is due to the speed of the microphone. As Kiwi Greg pointed out, a good mic is expensive and the whole system needs to be able to record as quick as 20 micro seconds. Most mics of OSH meters work in milliseconds so a gunshot is well and truly past peak before it starts to pick up. Slow mics will record little difference between a suppressed and unsuppressed shot since both are over before the mic starts to pick up because they are 100 times slower than the speed required to record bullet sounds.

Maybe good 22 cans are in the 110 - 115 range but I haven't tested any of these. I tested one by request of a mate at the range when I was testing other cans and it was in the 122 - 124 range. It sounded to me about like most other 22 sub cans that are decent. Considering that the action sound of an AR15 will vary between 115 and 125 depending on where you measure it, low 120's is not bad. The rounds I used to get to the mid 120's was hand made using Amax 208 and Lehigh 194 with around 7.5 of LilGun. I should probably switch to a factory load like Hornaday for more consistent measurement of an international standard. In real world terms I was able to put three rounds into two pigs from 15 meters away one night before the rest figured out I was there using a closed bolt (plugged gas port manually racking). Well, actually the first round missed so I got in a bit closer and the next two hit with a delay in racking the gun before the next round.

Before I had sound test meters, I sent a can overseas for testing. By the time I got the can back, I had my own testing meter and using the same barrel length and the same mil spec ammo, the average results were within 1 dB(A) and all the numbers tracked from the other side of the planet. From my experience, some of the factors that make a suppressor sound louder to the user like reflective surfaces or weather have more to do with the perception due to the length of time the sound is reflected to the ear rather than the sound being measurably louder. If you use international standard testing methods, the right metering equipment, same barrel length, action type and ammo, you will be able to reproduce testing within 2 dB(A) anywhere in the world.

Thanks for the post and the can, ODL - couldn't be happier with it all.

Slightly off topic, but I didn't want to make a new thread: for E cat... do you require two current E cat holders for your references? I've heard conflicting things from Police that have come into work and what I've read online