SpudFiles

Well, Im back with a new valve I machined myself for my .25 Gunpower stealth airgun.

Decided to shoot some airsoft BB's and see how fast they were going.

Im uploading the video evidence at the moment.

My control was a 20.1 grains H&N Field Target Trophy pellet = 1026 (There was a 1062 fps but I put that down to having the angle to the chrony not correct. The gun is 2000psi regualted so it is VERY consistant. All shots are within 10fps using airgun pellets

0.2g airsoft BB's were cracking at 1520 fps

0.12g Airsoft BB's were screaming at 1652 fps

Remember, this gun is firing on 2000psi...... yes 2000

So, how much faster do you think they could go with using regular air?? I was thinking around 1600 was the limit

I will update with the video

Dave

EDIT: Here is the video

[youtube][/youtube]

Impressive!

Not do doubt your results, but the muzzle blast seems to be reaching well over the chrony sensors and this could interfere with the reading. Have you tried moving a bit further back?

Ive actually got a video of me shooting a pellet, and then a BB.

Granted it was from my first attempts and they were moving around 1350 but you still hear the crack.

Let me see if I can find it.

Ive used the chrony with pretty much the barrel maybe a few inches away from the first sensor, never had a High/Low reading. How do you think the Combro chrony works, the muzzle can't be far away from the first sensor, and I know it has been consistantly used on airguns over 100 FPE

Dave

hey nice. is this a from one of the buckley books bc i know from reading the books that his valves are very similar to the gunpower stealth rifle

Dave_424 wrote:How do you think the Combro chrony works, the muzzle can't be far away from the first sensor, and I know it has been consistantly used on airguns over 100 FPE

Unfortunately the Combro is prone to this problem, I remember it suggests my Skif is doing 5 ft/lbs when really it's not doing more than 3, and when tried with some high power airguns like the Shinsung Career, we only got good results when using a silencer.

Again, not trying to rain on your parade, just trying to be sure you're getting the right data

Ive found the video of the supersonic crack, it is processing now.

Granted, the rifle in test using the combro was using a silencer.

You will see in the video, I first shoot a pellet and then the BB

Im using a SAK moderator.

Dave

Sorry for the double post but kinda relevant

Well, here is the long awaited proof

Note that I stuck the BB into the tip of the valve. There is a sharp edge there and it holds the BB so it doesnt roll down the barrel

[youtube][/youtube]

Dave...can you "dry fire" (quack fire.. ) over your chrony and post the results?

I've an F1, which doesn't seem to read the muzzle blast...despite popular opinion to the contrary. Others with F1's have noted the same result...curious how consistent this finding is.

I would be happy to, im using a Silencer/Moderator/Suppressor. But it isn't the best, it was cheap but it looked cool

I won't do it without the silencer because of neigbours

Dave

Neighbors are a "fact of life"...

Mind...my nearest neighbor is almost a mile.

Thanks

1600fps+ is SMOKIN' good job on the valve.

Well, I have a neigbour either side of my 20 yards wide garden They are actually GREAT. They do put up with a lot of my noise

Results are in:

Basically, there were no readings at all from the chrony or errors even up to 1" away from the first sensor. It is a cold day today and there is a much more pronounced muzzle blast in this weather.

Until I got to about 1/2" there was an ERR 2. But that was it. A lot less sinsitive with air than people think. CO2 on the other hand......

Thanks Geppeto, The valve is actually for my .308 big bore build, so there is a bit of dead space in the 10mm ID breech. 1600 FPS can definatley make your ears ring.

Dave

Dave_424 wrote: But that was it. A lot less sinsitive with air than people think. CO2 on the other hand.....

my 3 inch porter would beg to differ

Well..... up to the size that the launcher could effectivley launch the Chrony with its muzzle blast, my statement stands.

Maybe it is dirt/debris from your launcher or projectile that would cause a false reading. A piece of potato would definatley be recognised by the lights.

Dave