My First Attempt at Calculating FPS/FPE

Wonder how well it would stay put on other guns or having the chronograph on a stationary platform.dangit I want one now

outdooorgb said:

The Avenger is new to me and my first PCP. I wanted a chronograph and they are not free. During a search I found someone who checked out the inexpensive VIKKA at $33.
As far as accuracy? I believe I'm in the ballpark but really what I have is a baseline. Someone online compared two stings, one from this unit and one from a higher end with similar results.

I bought this: https://www.amazon.com/dp/B08DRJ3JW7?psc=1&ref=ppx_yo2ov_dt_b_product_details

And set everything up today. Took 21 shots for no particular reason. You can see my results below for the Avenger and another for the HW97k. Both in .22
The unit can be set in fps, mps, and joules (with input). I just chose to record the mps and build an excel sheet to save.

View attachment 325371View attachment 325372View attachment 325373

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Good job on gluing a piece of wood? in the middle to protect the far light. Wished I had thought of that before shooting out the far light on my first chrono.

The China device can be set to FPS. I have not figured out how to switch, could you explain?

I have that exact chronograph. When you power on the device, it'll say On, then 888.8, then wait til it says PS then hit the button once and it'll say and swap to FPS. Never programmed mine and can't confirm it's accuracy. When I increase HS the FPS goes up, so it's gotta be close! Lol Also like how it can clamp down, and how light/portable it is. Definitely worth the $

Thank you Tim, I will try that in the morning.

Good luck!

@outdooorgb that is a neat little unit. Thanks for sharing it with us. If you want to validate either the machine or your fps and/bc the Strelok Pro app has a function for that. It compares pellet drop between the scope's zero yardage with a further shot down range. Of course you can do the same math too, just like Strelok Pro does, but there all kinds of useful tools in it as well.

EmptyTin_Tim said:

I have that exact chronograph. When you power on the device, it'll say On, then 888.8, then wait til it says PS then hit the button once and it'll say and swap to FPS. Never programmed mine and can't confirm it's accuracy. When I increase HS the FPS goes up, so it's gotta be close! Lol Also like how it can clamp down, and how light/portable it is. Definitely worth the $

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The clamp-on version only has 3 digits. Not 4 and never displays 888.8 when "booting up".

So you do not have the "exact chronograph". You may have the other version, but not the clamp-on version.

Yes mine is the 3 digit as shown in the Amazon link. That is it exactly and only displays mps.

Outdoorgb’s photo shows a 4 digit. Did you order from that link and get a 4 digit clamp on?


But this one is the 4 digit found at the bottom of the page.

How does this device measure speed? There doesn't appear to be a light source required, but I doubt that it uses radar technology.

Two little LEDs. I read where a guy shot one and replaced it with one out of a tv remote.

It works in the dark. I bought one because I couldn’t get a Caldwell to work in my basement, and I didn’t want to fool around with light kits. This, for me, works so munch better, especially from a convenience standpoint. No set up, clamp to the moderator and shoot. That also keeps me from shooting the device. There is a huge thread on GTA about these. Well worth $30.

It does change the poi, so be mindful of that. Test speed and accuracy separately, and don’t shoot the wall...DOH!!!

The on off button stuck on my first one after almost two years.

BackStop said:

The clamp-on version only has 3 digits. Not 4 and never displays 888.8 when "booting up".

So you do not have the "exact chronograph". You may have the other version, but not the clamp-on version.

Click to expand...

Sorry but I can't imagine what would make you think you can know what I "do not have" when it's literally the same one as in Post #1's link, as I said. I clicked that Amazon link and it says "purchased on xxx xxx date" at the top.

Anyway, here is proof showing my clamp on version. Which says... "Clamp-style" right on it.


Here's a picture of the underside that shows the sensors that capture the light from the 2 bulbs on the bottom. Pretty cool how it works!

And here are the instructions that came with mine in case someone wanted to try some different settings out. I just swap to FPS and don't do anything else. But if you want to there are multiple functions.

Sorry this is sideways:

MY too ! i bought the 3 digit one and yes you can program the one i got $27 /Amazon , checked against Caldwell and it was one digit off /on .
LED's are in the unit

The only difference I see is my clamp on only has 3 digits and on the top says 1-999 mps.
I think they have sold enough to the US market that they are now making the 4 digit fps version.
With instructions!!! Mine some in Chinese.
Can’t be beat for $30

Yeah I got mine last June. So the 4 digit, FPS version been out a little while, and I do not do metric well. Lol So like it was stated yes it does reset every off/on so you have to swap to FPS. But real easy, just power on, wait for it to say PS then hit the button once and it says FPS.

Mine also came with the Chinese instructions but I was glad it also has English.

Great idea to add the shrinkwrap! Thanks for that-I'll have to copy you.

PS what do you think of your Buck Rail LDC? I got one and think it's a good design, it helps but doesn't make mine silent. Can't complain for the price though.

My HW30 loves the 7.33 AA Falcons. Pushes them @680 or so. I mostly shoot wadcutters through it. 7.0 usually tickle 700fps.

Nice chrony. I have one also. I had no idea it could be set to FPS until just now!
I don't use the u-clamp. I just use a couple of rubber bands to hold it to the muzzle. The u-clamp won't fit over a tatsu moderator.
Edit... I just looked at mine. It's the 3 digit and can't be set to FPS...