Suppressors Significant SD decrease and overall velocity increase - PopStop/SiCo Harvester/260REM

[DiscreetBallistics]

Got some results back today from a a former SF sniper we sent a 5/8-24 PopStop to for evaluation. For those unfamiliar, the PopStop was conceived as a method for eliminating First Round Pop and First Round Flash. The device itself is a machined titanium interface between muzzle and silencer with an external valve allowing for injection of CO2. We've received independant results from Bill Arevelo showing significant sound reduction when he tested it using his array of 2209s. However, we did not anticipate such significant reduction in velocity SD and increase in overall velocity with precision rifles.

Results can be seen here:

Here are the shooter's notes:

I honestly thought that something was wrong when I started testing this. While using the pop-stop on a suppressed rifle, it performed phenomenally. It was stupid quiet. This weekend I rehashed the data, and pulled this chart from my Magneto-speed Chronograph (Version3). Both my shooting partner and I had the same consistent results… Lower standard deviations of muzzle velocities, higher feet per second velocities, cooler barrels, no mirage—even when using a suppressor. I ran reloads as well as factory ammunition. The data is attached, with all pertinent info. This is a HUGE find and needs to be advertised. Running the POP-STOP with an extension line to my rifle and using it between shots cools your barrel enough to make your cold bore shot repeatable. All groups were under an inch/SUB-MOA, and it was tested with a Silencer-co Harvester Can which after shooting, I could remove without gloves. I have to get a sturdier extension line, probably steel braided on the outside, but the concept is there, as is the data. Now, please make a pop-stop that is bored out for 458 SOCOM!!

Here is a video of the PopStop in action by a youtube reviewer (KitBadger) who demonstrated it with some of our 308 subsonic ammunition:



As some of you may know, our company Discreet Ballistics is first and foremost a subsonic ammunition development and manufacturing company. PopStop was conceived as a way to make shooting with suppressors quieter by eliminating FRP. What we're seeing now is some data which suggests that there are benefits of PopStop that go beyond the auditory and visual spectrums.

So let's hear your thoughts. I promise, You won't hurt my feelings...

 

[TBACRAY]

I have one. I will get some testing done soon. Sorry for delay

 

[Sowastrong Industries]

following. intriguing to say the least

@Sapper524

 

[DiscreetBallistics]

I have one. I will get some testing done soon. Sorry for delay

No rush, Ray. But will definitely appreciate more independent data from long range shooters.

 

[DiscreetBallistics]

following. intriguing to say the least

@Sapper524

fluid dynamics = very intriguing

 

[Sowastrong Industries]

Went back and forth with a buddy over the useless vs usefulness of this. I wouldnt run one at a match but for hunting out of a stand with neighbors reducing that first round's dB's would be a bonus.

 

[DiscreetBallistics]

Went back and forth with a buddy over the useless vs usefulness of this. I wouldnt run one at a match but for hunting out of a stand with neighbors reducing that first round's dB's would be a bonus.

It works very well at completely eliminating FRP that's especially present with larger volume cans. Thanks for your comment about not running it in a match. Could you please elaborate on this? Thanks!

 

[Sowastrong Industries]

For that match setting...if I’m reading the results right you’re seeing changes in velocity and if so, unless I’m charging the can during the course of fire, I’d see SD swings. Maybe I’m miss understanding the application schedule but I guess I assumed you need to charge it up frequently if not every shot?Adding another set of threads to work loose potentially would be a concern. Added length, minimal but still.

 

[DiscreetBallistics]

Very helpful, thank you. You are reading the results correctly. It would appear from this data, velocity deviation is reduced as a result of creating a relatively pure and consistent CO2 atmosphere in the can which is accomplished by purging before every shot is taken. However, just as the subsequent shot is typically quieter than the first (traditional FRP without using this device) as a result of the lack of oxygen in the can, it can be posited that the propellant gas remaining in the can could act in a similar fashion as the pure CO2 environment - less turbulence, and therefore less velocity deviation. This is something I will check today.

 

[W54/XM-388]

Very interesting idea.
What would happen if you had a suppressor hooked on as normal and just stuck a nozzle down the end of the tube and gave it a quick squirt of CO2 from a small bottle?

 

[DiscreetBallistics]

Very interesting idea.
What would happen if you had a suppressor hooked on as normal and just stuck a nozzle down the end of the tube and gave it a quick squirt of CO2 from a small bottle?

It has a similar effect. However, we've found that the atmosphere is best purged with CO2 from behind the can with a round chambered - directly into the blast baffle and out the end cap. Also, not a great idea to stick something in the can with a round chambered.

 

[W54/XM-388]

I would assume you could also possibly make these serve double duty as thread adapters which could be good for sales, since if you had to buy an adapter anyways, you could just get one of these instead.

I'd be interested in trying one out that would adapt the HK pistol threads.

 

[DiscreetBallistics]

I would assume you could also possibly make these serve double duty as thread adapters which could be good for sales, since if you had to buy an adapter anyways, you could just get one of these instead.

I'd be interested in trying one out that would adapt the HK pistol threads.

We currently make them in 1/2-28 and 5/8-24. These could serve double duty as thread adaptors - albeit large ones.

 

[DiscreetBallistics]

More data this time using one of our test guns (18" savage action in chassis w/ Q Full Nelson silencer) with our commercial 308Win subsonic in Lapua brass from same sleeve/lot # etc. Magnetospeed V3 chrono

At least from this small sample it appears that a single injection of CO2 before the series of 5 results in smaller SD than injections before every shot. Maybe it has something to do with the cooling factor of the CO2 injections. I'll have to get my thermals on it for the next test...

 

[DiscreetBallistics]

FYI PopStop patent was issued a few days ago. We're continuing to gather data related to the increased muzzle velocity and decreased velocity SD findings.