Scatt live fire recoil anomaly

Flow · Post by **Flow** » Sun Jul 03, 2011 4:58 am

Hello everyone.

I have noticed that the recoil trace of a .22 rim fire always starts off in the direction of the sensor. ie. If the sensor is mounted underneath the barrel the first movement of the recoil is down. I noticed this was the same with the but plate high or low and even with the rifle free recoiling on a rest so I mounted the sensor horizontally to the left and to the right and the first movement of the recoil was now off the the left or right respectively. Very strange.

I tested this on multiple .22 rim fire rifles and got the same result.

Does anyone have any ideas why this might be happening?

Many Thanks
Jason Williams

mangusta · Post by **mangusta** » Sun Jul 03, 2011 6:21 am

It's possible that the recoil movement of the barrel is far too rapid for the sensor to correctly detect the barrel movement. So the system is only effectively picking up when the sensor moves toward the emitter point. Could be just a limitation of the system.

Flow · Post by **Flow** » Sun Jul 03, 2011 1:05 pm

Thanks mangusta.

You can see that the sampling frequency is having trouble keeping up with the barrel movement as some of the lines are not well smoothed but it is not so bad that it would indicate missing half of the first oscillation.

What is the sampling frequency of the Scatt? The Noptel is 67Hz.

I thought it might be the fireing pin hitting the base of the round but then you would see it in dry fire sessions which you don't. The other idea I had is that may be it is the downward bend of the barrel in the first stages of barrel whip but that is a bit far fetched.

Any other thoughts. Recoil analysis is a really important part of .22 Long rifle shooting development. It would be good to be able to trust the system to give you accurate results.

All the best
Jason

mangusta · Post by **mangusta** » Mon Jul 04, 2011 6:44 am

I'm not sure if what the resolution of the scatt system is, however I do know that it uses a microphone to detect the point of fire, perhaps the sound of the firing pin, then the shot, then the shot leaving the barrel is causing confusion also as it may think it has detected multiple shots?

The website mentions it being adjustable, perhaps see if you can turn that up and see if it clears it up.

We have never used the scatt setup live fire at our range, I will make a point of asking the guy in charge of it, he has had training and might know about live fire use...

Guest · Post by **Guest** » Mon Jul 04, 2011 7:14 am

Thank you very much for that mangusta. I know how to adjust the piezoelectric mic settings.

I am beginning to wonder if it is a resolution issue. The most realistic looking recoil traces were when I set up with a whole lot of padding under my elbows. I certainly hope it is not as I just ordered one of these instead of a noptel.

I look forward to your findings.

Many thanks
Jason

Guest · Post by **Guest** » Wed Jul 06, 2011 3:10 pm

Hello again everyone.

I have just had a look at all of our live fire traces from all of our shooters and all of them bar none have downward recoils.

Any news mangusta

David Levene · Post by **David Levene** » Thu Jul 07, 2011 1:04 am

Have you tried asking Scatt or the importer in your country?

The level of knowledge will obviously vary from importer to importer.

Scatt are not always the quickest at answering questions but they usually get there eventually.

Guest · Post by **Guest** » Thu Jul 07, 2011 5:31 am

Hey David.

I have asked the Scatt people and the Czech support guys to answer this thread. But no luck so far.

It is an important issue with regards to the value of Scatt live fire traces.

I trust they will make it a priority.

Cheers
Jason

David Levene · Post by **David Levene** » Thu Jul 07, 2011 5:49 am

Anonymous wrote:I have asked the Scatt people and the Czech support guys to answer this thread.

I would very much doubt that Scatt will answer this thread. You would probably get a better response by just asking the question in an email and expecting an email response.

If you don't get an answer in 7-10 days then send them a reminder, and repeat that every 7-10 days.

Flow · Post by **Flow** » Sun Jul 10, 2011 6:15 am

Hello everyone.

It seems that the sample frequency of the Scatt is no where near fast enough to be able to capture the initial recoil. Which I have to say is rather disappointing. From a few basic calculations it would have to be in the order of 600 hz to be able to get a clean capture of the initial recoil. The reality is that it is probably less than one 10th of that.

A friend here in New Zealand is looking at developing a complete barrel instrumentation / recoil analysis system which should be able to give a much more complete and usable data. I will let you know how that goes.

Thanks again for all your thoughts
Jason Williams

David Levene · Post by **David Levene** » Sun Jul 10, 2011 7:49 am

Flow wrote:From a few basic calculations it would have to be in the order of 600 hz to be able to get a clean capture of the initial recoil. The reality is that it is probably less than one 10th of that.

The last time I looked at the raw data from Scatt it was sampling at 200hz.