Rate of Fire Meter or Smartphone APP

[reconbob]

Hello all -

 

I need a rate of fire meter or detector - we are checking the effects of different length recoil springs and buffers on rate of fire. I can't seem to find a meter but there are numerous APPs mostly for timing shots for combat type matches. Would such an App be able to detect the rate of full auto fire? If not any other ideas. I have searched the Internet but I suspect the "rate of fire" search terms is not taking me where I need to go.

 

Thanks in advance

 

Bob

[DINK]

You will probably have more luck searching "shot timer". I use the PACT Mk IV, which has a specific function for cyclic rates. Sorry, but I have no idea about apps for smart phones other than they are out there. Here's a site that supposedly compares them: http://appcrawlr.com/android-apps/best-apps-shot-timer

[Grasshopper]

Hi Reconbob,

 

There were some posts about a year ago concerning someone using a smart-phone app to get cyclic rates. IIRC it concerned a Sten Mk2. The results of using the app were dismal at best. The app would not accurately determine the cyclic rate.

 

YMMV,

 

Good Luck,

 

Grasshopper

Edited October 15, 2016 by Grasshopper

[Kilroy]

Hi Arch,

 

There were some posts about a year ago concerning someone using a smart-phone app to get cyclic rates. IIRC it concerned a Sten Mk2. The results of using the app were dismal at best. The app would not accurately determine the cyclic rate.

 

YMMV,

 

Good Luck,

 

Grasshopper

I've heard the same thing that the apps are no good for actually determining cyclic rate, but can be used as a stop watch that will time your first and last shot. Then a little bit of math homework can yield cyclic rate... rounds fired is a known number, divided by the time difference between the first and last shot gives you shots per second, times 60.

[Merry Ploughboy]

From what little I've read, the smartphone microphone (which is designed for vocal response, not firearms muzzle noise response) is blamed for at least some of the erroneous smartphone results. No matter how good the arithmetic is, bad data in gives bad results out. I'd stick with a device that is specifically designed for the task. There are several brands that get favorable reviews and are in the same price range.

 

MHO, YMMV, etc.

[buzz]

If you make a video of a 30 round mag dump and then play it back and use a stopwatch, you can get pretty consistent results with some practice.

 

not an ideal method, but decent

 

Multiply 60 seconds by 29 (not 30) and divide by the number of seconds you click off on the stopwatch

 

and you have your ROF in rounds per minute

 

suppose you get 1.75 seconds on the stopwatch to fire 30 rounds

 

60 x 29 / 1.75 = 994 RPM

Edited October 10, 2016 by buzz

[Grease Gunner]

Here is how to calculate in a foolproof way the cyclic rate.

Use a pact or other timer.

When the beep starts and the shooter fires......The timer will definitely get the first and last shot but not all the shots in between

It is IMPERATIVE you count the rounds to be fired and subtract 1 , or use a 30 round mag and subtract how many were not fired in your burst

 

Whats important to all this is to know the timer records when the first shot goes off and when the last shot goes.

Subtract and thats your interval(the burst time) Then divide the seconds by the number of rounds fired and dont count the first round since we are working with the burst time which is the time between the 1st shot and the last,hence the reason we do not count the first round when we divide.There is no gun time related to the first shot.It's just is a starting point on the timer

 

Example first round fired in .40 seconds,last shot fired at 2.30. Subtracting will yield 1.9 seconds for the string

We know the shooter fired 21 rounds. Thats 1.9 seconds for 20 rounds=10.52 per second x 60= 631 RPM

Simple math tells you divide the time by the number of rounds fired less one to get how many you fire in a second,

then multiply x 60 to get cyclic rate

 

 

Conversely, a 600 rpm rate will fire on average 10 per second - in 2 seconds 20 would be fired- 10 per second x 60= 600 rmp

 

Hope this helps. I have been doing this on AR-15s for years with slide fire stocks and I get 500 to 550 per minute. Poor mans M16!!!

Edited October 14, 2016 by Haris357

[buzz]

Haris, you need to subtract one from the total number of rounds (21) and divide with that number (20).

 

Look at it this way -

 

Suppose you have a real real slow machine gun that fires one round per second.

 

You shoot five shots. The first shot will start the recording at say 0.5 seconds, the second shot will come at 1.5 seconds, the third at 2.5, the 4th at 3.5 and the 5th at 4.5 seconds

 

Your total time for the string is 4.5 seconds - 0.5 seconds = 4.0 seconds.

 

There are 5 shots but only 4 intervals take place between the first and last shot. That's because there is no gun-cycle time associated with the first shot.

 

To get the actual rate of fire you take 4.0 seconds / (5 - 1 shots) = 1.0 seconds per shot

Edited October 12, 2016 by buzz

[Grease Gunner]

Haris, you need to subtract one from the total number of rounds (21) and divide with that number (20).

 

Look at it this way -

 

Suppose you have a real real slow machine gun that fires one round per second.

 

You shoot five shots. The first shot will start the recording at say 0.5 seconds, the second shot will come at 1.5 seconds, the third at 2.5, the 4th at 3.5 and the 5th at 4.5 seconds

 

Your total time for the string is 4.5 seconds - 0.5 seconds = 4.0 seconds.

 

There are 5 shots but only 4 intervals take place between the first and last shot. That's because there is no gun-cycle time associated with the first shot.

 

To get the actual rate of fire you take 4.0 seconds / (5 - 1 shots) = 1.0 seconds per shot

Buzz, Thank you for the correction- You are 100% right on. I forgot that the first shot has no gun time. Changed my calculation downward by 5%

Edited October 14, 2016 by Haris357

[atreo]

Hello,

 

Apparently a new App for measuring the rate of fire of automatic weapons is about to be launched this January. It has been developed by the Austrian company TACTICALMEASUREMENTS. It's perfect for weapon tuning enthusiasts but it also has a server back-end to be used in professional manufacturing environments.

 

Check it out here: tacticalmeasurements.com

 

Probably you can also become a Beta-Tester by contacting the guys at info@tacticalmeasurements.com

 

Best,

 

Atreo

[ppgcowboy]

Anyone get a chance to use this yet? I have it downloaded but have not yet had a chance to try it since its release.

[ppgcowboy]

I finally got to do a test. My Navy with Pk 21 actuator and buffer assembly showed 909rpm and my ar15 with a slide fire at 765. I will put in the 28 actuator next time I break out the toys.

[Roland the Thompsongunner]

I tried to download it and it wont work for the apple phones. Im bummed

[ppgcowboy]

I have an Samsung.

[shadycon]

You have to love modern technology!!!!!

[ppgcowboy]

28 actuator clocked at 730rpm.

[Roland the Thompsongunner]

I tried the app on my kids phone today with two guns. With the 22 kit in the 28 Thompson i got 819 rpm. My PPSH41 with new Tulammo 7.62x25 got 1186 rpm. Its seems to work pretty good. I am exited to try some other guns when I get a nice day.