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Scatt question.

Posted: Fri Feb 17, 2012 5:55 pm
by Roadthing
Does the distance you use the scatt for dry fire training matter? Is the feedback the same from different distances? I have just under 10m in my house to play in.

Doug K

Posted: Fri Feb 17, 2012 6:10 pm
by tenring
I've heard ten meters is optimum for whatever reason, but I use mine at 5 meters and it works perfectly. Its very sensitive at 5 meters, maybe easier the further out to 10 meters you get. I don't know. I would think math is math and is the same though. It should be just fine.

Tenring

Posted: Fri Feb 17, 2012 6:15 pm
by Roadthing
tenring wrote:I've heard ten meters is optimum for whatever reason, but I use mine at 5 meters and it works perfectly. Its very sensitive at 5 meters, maybe easier the further out to 10 meters you get. I don't know. I would think math is math and is the same though. It should be just fine.

Tenring
Cool that is kinda what I wanted to hear.

Doug

Posted: Fri Feb 17, 2012 7:23 pm
by KennyB
Mine seems to give longer trace lengths when I use it at 10m at the range compared to when I use it at 5m at home. I don't know why but they seem to be about 25% better (shorter) at the lesser distance.

Ken.

Posted: Sat Feb 18, 2012 12:17 am
by David Levene
Errors break down into 3 types:-

1) Parallel errors - where the front and rear sights are correctly aligned with each other, just pointing at the wrong place on the target. A 10mm error at 5m would be the same 10mm error at 10m.

2) Angular errors - where the front and rear sights are not correctly aligned with each other. Accepting small differences due to the positioning of the sensor beyond the firing line, a 10mm error at 5m would actually represent a 20mm error at 10m.

3) A combination of parallel and angular errors. These could actually result in a "10.9" at 5m which would actually have been a lesser score at 10m.

Now comes the crunch. Scatt/Rika/Noptel/etc can only detect the result of an error, not what caused it. Certainly Scatt, and I believe the others too, treats all errors as if they angular, multiplying them for the represented target distance.

A 10mm parallel error at 5m would therefore be incorrectly reported as a 20mm error at 10m.

A combination error will be incorrectly extrapolated to some degree including, as in the example above, incorrectly reporting a perfect shot.

Posted: Sat Feb 18, 2012 11:14 am
by RobStubbs
One thing I would suggest is that you always use the same distance. I try and use 10M wherever possible, but sometimes 7m is all I can use. Personally I wouldn't use 5M for rifle, but if that's all you can get, it's better than nothing.

Rob.

Posted: Sat Feb 18, 2012 3:08 pm
by tenring
Why not 5 meters? just wondering what you have discovered?

Thanks,

Tenring

Posted: Sat Feb 18, 2012 3:35 pm
by RobStubbs
tenring wrote:Why not 5 meters? just wondering what you have discovered?

Thanks,

Tenring
A combination of the angular errors David mentions and from feedback from others more experienced with scatt than I am.

Rob.

Posted: Sun Feb 19, 2012 7:05 am
by RobinC
I have my own Scatt and also coach on our club one, and they definately work better at distances over 5 mts, 7 to 10 is best.

We used our home one at 3.5 mts for a while and it was very problematic, 5mts is OK, but 7mts is better, we had problems with groups moving for no logical reason, and other irritating things I can't remember. Don't ask me why, leave that to David as I'm the kiss of death to computors, but trust me they are better at longer distances.
Good shooting
Robin

Posted: Sun Feb 19, 2012 9:03 am
by KennyB
I'm thinking that because SCATT initially calibrates to the distance between the target and the sensor, if the sensor moves closer to or further from the target during training, it will appear as a vertical shift in the group.

This is particularly noticeable if you break, get up, get back down and continue - when I do that I find that the first shot of the next string is usually low in the 8 ring...
Lesser shift may occur if your position collapses as you shoot - the more you sag the further forward the muzzle goes and down goes your group.

Knowing this helps to explain some of SCATT's idiosyncrasies.

The longer the distance, the smaller this error will be in percentage terms - so longer is better.

You can still get an awful lot of good data shooting at 5m - if you know how to interpret it.

Ken.