One evening after only a few ales, very wise friend of mine once remarked "You can only do two and a half things well at a time."
This immediately struck me as an enormously smart thing to say for a variety of reasons. Firstly, it states that there's a limit to the number of things you can do well at any one time. Secondly, it implies that the limits of your ability are not quite as simple to define as it might appear at first glance. Finally and perhaps most importantly, it recognises that when you don't do something well, you'll either not do it all or you risk doing a half-arsed/assed* job of it.
This observation is important to rifle shooters because the vast majority of us are amateurs who to work in addition to training for our sport and managing our lives outside shooting. We have to decide which two and a half things to focus on.
Here I have good news and then again, I have some bad news.
The bad news is that if you've not either incredibly talented or you've already achieved a high level of competence, then you have to make shooting one of the two things and not a "half" or a "no" thing if you want to make significant and sustainable progress. For the vast majority of us whose initials are not GCDB there really isn't a good substitute for quite a bit of hard work in training and on the range. This quite naturally has consequences for the other things that you do in your life. Some significant others may object to you SCATTing in the living room while they watch Criminal Minds over the top of you lying on vaguely doggy-smelling shooting mat.
The good news is that compared to, say, marathon running or rowing, the amount of actual training you need to do is comparatively light. For example, to complete a marathon in under 4 hours (i.e. Marginally better than only half as fast as Mo Farah) you need to run about 30 - 40 miles per week (including one long run of 16 - 20 miles) which works out at about 6 hours per week of running at the appropriate pace. The top endurance athletes run well over 100 miles per week, albeit at a much faster pace than 09:00 minutes per mile, on top of which they spend numerous hours in the gym working on their core strength, flexibility and running form. If you spend even two hours on SCATT, an hour on visualisation and another hour or two on a bit of cardio and light weights, you will be streets ahead of most other fullbore shooters and are likely to make significant performance gains as a result.
Pick your two and a half things wisely.
* Delete as appropriate according to preference, cultural heritage etc...
Saturday, 27 June 2015
Saturday, 20 June 2015
Interpreting SCATT Results, Part 3 - Comparing Techniques, Positions and Equipment
Before we get started, this post is long, quite technical and makes for dense reading; although I do include an executive summary at the end. I make absolutely no apologies for that whatsoever. Comparing techniques, positions and equipment is an important topic and it is surprisingly hard to make comparisons that are truly discriminatory and not the result of chance. Very many people have made comparatively minor changes to position or technique, subsequently had one good result and declared victory against all ills in their shooting - real or perceived - only to find out after a few more shoots that they've not really resolved anything.
Why is it so hard to make real comparisons?
The short answer is "statistics". For a longer answer, read the tale of woe which follows...
You get the idea. The point here is that even though the change is detrimental to the shooter's performance, there is still a finite probability that they will get a score which is above average for them using their previous technique. The shooter needs to make several measurements to have a better understanding of the performance profile which results from the change. The more measurements, the better the understanding.
In summary, it is entirely possible to make a detrimental change and yet have one or more better-than-average shoots afterwards. This is something best avoided.
How do we use SCATT to make good comparisons?
One of the key uses of SCATT is the comparison of different techniques, positions and equipment prior to testing them in a livefire training session. The feedback that SCATT, Noptel, RIKA or another similar shooter training system can provide is worth a very great deal for a number of reasons:
Firstly, dry firing with such a system provides quantitative feedback in addition to the qualitative "feel" of trying something new in a simple dry fire or even a live fire environment. The trace length, shot release and shot aim data allow direct comparison of the different elements of groups of dry shots fired under different circumstances.
Secondly, the marginal cost of dry firing with a SCATT is essentially zero, so the only limit on the number and quality of tests that can be done is the amount of time that you are willing to spend upon testing. This allows much more reliable and detailed comparison than one done on a rifle range with live ammunition, where the cost of ammunition, target time and barrel life becomes a significant factor very rapidly.
There are five guidelines to making a good comparison using a shooter training system:
In any good experiment, one change and one change only is made between tests. If you make two changes then you test, then you don't know what the effect of each individual change is. So if you wanted to make two changes, you should test each change individually and then both changes together (as well as the tests needed to establish your baseline.) Of course, this presents us with an issue because if you want to play with lots of different settings, such as when you've just bought a new rifle with lots of spiffy adjustments to make, in theory you can end up with hundreds or even thousands of tests to do. To get around this, you should apply some common sense to a) reduce the number of tests you need to run, e.g. you can probably test eye relief as a discrete test once you've picked the remaining settings for your position, and b) eliminate the obvious no hopers, e.g. with some handstop settings your sling may be obviously too tight or obviously too loose.
It is critically important that you record everything for two main reasons: Firstly, if something doesn't work out, e.g. a handstop position, then you need to be able to revert to your baseline settings, but also so you can keep an accurate track of the changes you made and the results you got. Reproducibility is the key; there's no point doing a bunch of comparison tests to find the best position for you if you can't reproduce it once you've identified that it is the best position.
The key limitation to understand is that SCATT and similar systems are not perfect in their modelling of shots, so it is a very real possibility that you're not going to get the perfect position for live shooting from SCATT training; however what it does allow you to do is to make useful comparisons
Real life example; comparing underlayers
OK, so Kat, the kids and I moved to NZ. I had some (but not all) of my shooting kit with me and my new jacket arrived. I didn't have any underlayers with me for the Nationals so I shot using wearing a hoodie under my new Creedmoor jacket. In the fullness of time, the rest of our stuff arrived in boxes, including all my old underlayers. This left me with a dilemma: Did I continue shooting with the hoodie or did I revert to using my Kurt Thune coldwinner top?
Enter SCATT and Excel.
I fired a bunch of shots under as near identical conditions as I could make them, changing only the top I shot in. After doing a little calculation, I obtained the following results:
What this tells me is that shooting with the hoodie appears to provide a more consistent hold than the coldwinner top, all else being equal, because the average tracelength and shot release values are both lower (i.e. Better) for the hoodie. I can see that this is statistically very significant for the tracelength because the difference between the two average tracelength values is much greater than the standard error values. The difference between the two shot release values is not demonstrated to be statistically significant, as the difference between the two values is only about 1 standard error. Comparing more values may resolve this issue.
I'll be shooting in the hoodie at this year's Imperial Meeting. I also ran a similar comparison of low and high cheekpiece positions and found that the high cheekpiece position provided a better consistency of aim.
tl;dr version for company directors and other individuals with the attention spans of goldfish
SCATT is really good for trying out changes to your equipment, position or technique.
When using SCATT to compare changes you need to:
Why is it so hard to make real comparisons?
The short answer is "statistics". For a longer answer, read the tale of woe which follows...
Imagine a shooter with a performance distribution as labelled "Technique 1" in the above diagram. (S)he's not exactly a bad shooter, but can be a bit variable sometimes, so resolves to make a change. The change results in the performance distribution labelled "Technique 2", which is actually worse than the previous approach. The change has been detrimental; however the shooter has no way of knowing this yet, as (s)he hasn't tested it yet. In due time, the shooter goes and fires another competition and entirely by chance gets a 50! Elated with the positive impact on performance, (s)he goes and has a celebratory shandy on the North London RC verandah and announces to all and sundry that everything is sorted. During the next day's shooting, regression to the mean* rears its ugly head and scores are abysmal.
You get the idea. The point here is that even though the change is detrimental to the shooter's performance, there is still a finite probability that they will get a score which is above average for them using their previous technique. The shooter needs to make several measurements to have a better understanding of the performance profile which results from the change. The more measurements, the better the understanding.
In summary, it is entirely possible to make a detrimental change and yet have one or more better-than-average shoots afterwards. This is something best avoided.
How do we use SCATT to make good comparisons?
One of the key uses of SCATT is the comparison of different techniques, positions and equipment prior to testing them in a livefire training session. The feedback that SCATT, Noptel, RIKA or another similar shooter training system can provide is worth a very great deal for a number of reasons:
Firstly, dry firing with such a system provides quantitative feedback in addition to the qualitative "feel" of trying something new in a simple dry fire or even a live fire environment. The trace length, shot release and shot aim data allow direct comparison of the different elements of groups of dry shots fired under different circumstances.
Secondly, the marginal cost of dry firing with a SCATT is essentially zero, so the only limit on the number and quality of tests that can be done is the amount of time that you are willing to spend upon testing. This allows much more reliable and detailed comparison than one done on a rifle range with live ammunition, where the cost of ammunition, target time and barrel life becomes a significant factor very rapidly.
There are five guidelines to making a good comparison using a shooter training system:
- Build a baseline / control
- Change one thing at a time (but use your common sense)
- Record everything
- Do enough shots to make the comparison meaningful
- Understand the limitations of the system
In any good experiment, one change and one change only is made between tests. If you make two changes then you test, then you don't know what the effect of each individual change is. So if you wanted to make two changes, you should test each change individually and then both changes together (as well as the tests needed to establish your baseline.) Of course, this presents us with an issue because if you want to play with lots of different settings, such as when you've just bought a new rifle with lots of spiffy adjustments to make, in theory you can end up with hundreds or even thousands of tests to do. To get around this, you should apply some common sense to a) reduce the number of tests you need to run, e.g. you can probably test eye relief as a discrete test once you've picked the remaining settings for your position, and b) eliminate the obvious no hopers, e.g. with some handstop settings your sling may be obviously too tight or obviously too loose.
It is critically important that you record everything for two main reasons: Firstly, if something doesn't work out, e.g. a handstop position, then you need to be able to revert to your baseline settings, but also so you can keep an accurate track of the changes you made and the results you got. Reproducibility is the key; there's no point doing a bunch of comparison tests to find the best position for you if you can't reproduce it once you've identified that it is the best position.
The key limitation to understand is that SCATT and similar systems are not perfect in their modelling of shots, so it is a very real possibility that you're not going to get the perfect position for live shooting from SCATT training; however what it does allow you to do is to make useful comparisons
Real life example; comparing underlayers
OK, so Kat, the kids and I moved to NZ. I had some (but not all) of my shooting kit with me and my new jacket arrived. I didn't have any underlayers with me for the Nationals so I shot using wearing a hoodie under my new Creedmoor jacket. In the fullness of time, the rest of our stuff arrived in boxes, including all my old underlayers. This left me with a dilemma: Did I continue shooting with the hoodie or did I revert to using my Kurt Thune coldwinner top?
Enter SCATT and Excel.
I fired a bunch of shots under as near identical conditions as I could make them, changing only the top I shot in. After doing a little calculation, I obtained the following results:
| Top Worn | Shots | Average Tracelength | Standard Deviation | Standard Error | Average Shot Release | Standard Deviation | Standard Error |
|---|---|---|---|---|---|---|---|
Coldwinner
|
30
|
923.2
|
88.2
|
16.1
|
52.2
|
32.0
|
5.8
|
Hoodie
|
39
|
817.7
|
96.0
|
15.4
|
46.6
|
30.6
|
4.9
|
What this tells me is that shooting with the hoodie appears to provide a more consistent hold than the coldwinner top, all else being equal, because the average tracelength and shot release values are both lower (i.e. Better) for the hoodie. I can see that this is statistically very significant for the tracelength because the difference between the two average tracelength values is much greater than the standard error values. The difference between the two shot release values is not demonstrated to be statistically significant, as the difference between the two values is only about 1 standard error. Comparing more values may resolve this issue.
I'll be shooting in the hoodie at this year's Imperial Meeting. I also ran a similar comparison of low and high cheekpiece positions and found that the high cheekpiece position provided a better consistency of aim.
tl;dr version for company directors and other individuals with the attention spans of goldfish
SCATT is really good for trying out changes to your equipment, position or technique.
When using SCATT to compare changes you need to:
- Make sure you know your current standard of performance to act as a baseline
- Change only one thing at a time
- Keep an accurate note of the changes you've made
- Fire lots of shots with the change to make sure the comparison is a good one
- Recognise that SCATT isn't perfect
Thursday, 18 June 2015
Salmon Days
Ladies and gentlemen. Rifle shooters all. There will be days when you're all ready to train; you've prepared well and have a goal in mind for your training session, but despite your hard work it's all just a pile of poo.
For me, today was one of those days. It happens.
When this happens to you (and it will) check you're not doing something obviously dumb. Fire maybe a couple more shots. If there's no improvement, put the rifle down, tidy your kit away and do something else.
It is often said that practice makes perfect. It doesn't. Perfect practice makes perfect. Practice makes permanent whatever it is you're doing whether well or ill. You do not want to iron in crap technique, so when this happens to you as it happened to me this very evening follow my example: lock the rifle away, pour yourself a nice cold drink and write a blog post about it. Or go for a run. Or do some stretching.
Do not waste your time by continuing to train badly.
For me, today was one of those days. It happens.
When this happens to you (and it will) check you're not doing something obviously dumb. Fire maybe a couple more shots. If there's no improvement, put the rifle down, tidy your kit away and do something else.
It is often said that practice makes perfect. It doesn't. Perfect practice makes perfect. Practice makes permanent whatever it is you're doing whether well or ill. You do not want to iron in crap technique, so when this happens to you as it happened to me this very evening follow my example: lock the rifle away, pour yourself a nice cold drink and write a blog post about it. Or go for a run. Or do some stretching.
Do not waste your time by continuing to train badly.
Saturday, 13 June 2015
Bob's Fantastic GGG Teardown
My good friend, Commonwealth Games rifle shot and handloading guru Bob Oxford has done a great teardown of the UK NRA's new GGG ammunition to be used in the 2015 Imperial Meeting and potentially beyond. Great photos, measurements and technical data, and plots. What more could you need?
Bob's GGG Teardown
Bob's GGG Teardown
Friday, 12 June 2015
Interpreting SCATT Results, Part 2 - The Numbers
In part 1 of this series on interpreting SCATT results I talked about individual traces and a little bit about how to read them. Much of that is deduction really; working out what has evidently gone wrong from the evidence that the shape of the trace gives you. The focus of that article is on individual shots. By way of contrast, I find the numeric aspect of SCATT to be more focussed on groups of shots, and once you're into the domain of populations of numbers you are inevitably going to run into statistics; however in this article I'm going to ignore that as much as possible.
What I look at
SCATT tells you a massive amount of stuff, but I pretty much ignore everything except for four numbers. If we reduce shooting technique to "point the rifle in the middle, hold it very still and squeeze the trigger gently" then these four numbers give us a pretty good understanding of the three components of shooting and the overall quality of the result.
Individual Shot Numbers
The individual shot numbers are located in the panel on the left-hand side of the screen underneath the miniature diagram which shows all of the shots.
# - Shot number. Bit obvious this one really.
Result - Score of the shot. Ditto.
Time - Time taken between the trace entering the target zone and the shot being released. In the panel above, I'm taking too long. Once settled you should take between 2 and 8 seconds to get the shot away. Add a couple of seconds for transit from the edge of the target onto the bullseye and you should be getting them away in well under 10 seconds.
(Trace) Length - The distance travelled by the trace on the target in the final second measured in millimetres. Roughly correlates with how still you can hold the rifle. Lower trace length = smaller, slower wobble. On a 1000 yard target under 1000 is OK, under 800 is good, under 700 great.
10.0 - The percentage of the time that the trace is in the 10 ring. As I often don't bother to centre the group (repeat after me, SCATT is not a v-bull machine) I pretty much ignore this number.
Shot Release - The final column on the right-hand side, which seems to not have a label. The distance in millimetres between the centre of your wobble and where the shot ends up. This is a function of how fast the rifle is moving when the shot is released, which is related to position and quality of trigger release. Lower number = better hold and release. On a 1000 yards target 70 is OK, under 50 is good, under 40 is great.
NB - You can only really compare trace length and shot release values for the same distances,
Group Numbers
The group numbers are shown in the right-hand pane if you click on the "Info" button in the menu lower ribbon at the top of the screen (underneath the "Start" button.")
I'm going to skip most of the crap at the top because it's either self-evident or irrelevant and get straight to...
Diametrical dispersion (group size) - Self-explanatory but a really useful measure of your technique as a whole. I generally use SCATT to shoot groups without changing my sights, so this is a useful measure of how well I'm shooting.
Stability of Aiming - Incredibly useful. How consistently you are pointing the rifle in the middle. A function of the repeatability of your position, in particular your NPA and sight alignment.
Accuracy of Shooting - The distance from the centre of your group to the centre of the target. As I often don't bother to centre groups as I'm not using SCATT to try and get a score, I pretty much ignore this.
Average Steadiness in 10 - The average percentage of trace in the 10 ring for all shots.
Average Length of a Tracing - The average trace length for all shots.
Elliptical Factor - Measures how round your groups are. I ignore this as it's not terribly meaningful for fewer than 20+ shots, provided the group isn't really strung out.
Control Interval - The duration used for the calculation of trace lengths.
I don't tend to find individual traces that enlightening any more because under the controlled conditions of SCATT training I don't fire that many out and out bad shots, and I usually know when I've done it. It's in the warm with no wind on a perfectly consistent surface and with perfectly consistent lighting. As a result, the use of statistics on lots and lots of shots tends to be the only real way to disentangle fact from mere happenstance. In the next post of this series, I'll talk about using SCATT to compare equipment, techniques and positions.
What I look at
SCATT tells you a massive amount of stuff, but I pretty much ignore everything except for four numbers. If we reduce shooting technique to "point the rifle in the middle, hold it very still and squeeze the trigger gently" then these four numbers give us a pretty good understanding of the three components of shooting and the overall quality of the result.
- Stability of aiming - How good you are at pointing it in the middle
- Trace length - How still can you hold the rifle
- Shot release - How good your shot release is
- Diametrical dispersion (group size) - The overall quality of the result
Individual Shot Numbers
The individual shot numbers are located in the panel on the left-hand side of the screen underneath the miniature diagram which shows all of the shots.
Result - Score of the shot. Ditto.
Time - Time taken between the trace entering the target zone and the shot being released. In the panel above, I'm taking too long. Once settled you should take between 2 and 8 seconds to get the shot away. Add a couple of seconds for transit from the edge of the target onto the bullseye and you should be getting them away in well under 10 seconds.
(Trace) Length - The distance travelled by the trace on the target in the final second measured in millimetres. Roughly correlates with how still you can hold the rifle. Lower trace length = smaller, slower wobble. On a 1000 yard target under 1000 is OK, under 800 is good, under 700 great.
10.0 - The percentage of the time that the trace is in the 10 ring. As I often don't bother to centre the group (repeat after me, SCATT is not a v-bull machine) I pretty much ignore this number.
Shot Release - The final column on the right-hand side, which seems to not have a label. The distance in millimetres between the centre of your wobble and where the shot ends up. This is a function of how fast the rifle is moving when the shot is released, which is related to position and quality of trigger release. Lower number = better hold and release. On a 1000 yards target 70 is OK, under 50 is good, under 40 is great.
NB - You can only really compare trace length and shot release values for the same distances,
Group Numbers
The group numbers are shown in the right-hand pane if you click on the "Info" button in the menu lower ribbon at the top of the screen (underneath the "Start" button.")
I'm going to skip most of the crap at the top because it's either self-evident or irrelevant and get straight to...
Diametrical dispersion (group size) - Self-explanatory but a really useful measure of your technique as a whole. I generally use SCATT to shoot groups without changing my sights, so this is a useful measure of how well I'm shooting.
Stability of Aiming - Incredibly useful. How consistently you are pointing the rifle in the middle. A function of the repeatability of your position, in particular your NPA and sight alignment.
Accuracy of Shooting - The distance from the centre of your group to the centre of the target. As I often don't bother to centre groups as I'm not using SCATT to try and get a score, I pretty much ignore this.
Average Steadiness in 10 - The average percentage of trace in the 10 ring for all shots.
Average Length of a Tracing - The average trace length for all shots.
Elliptical Factor - Measures how round your groups are. I ignore this as it's not terribly meaningful for fewer than 20+ shots, provided the group isn't really strung out.
Control Interval - The duration used for the calculation of trace lengths.
I don't tend to find individual traces that enlightening any more because under the controlled conditions of SCATT training I don't fire that many out and out bad shots, and I usually know when I've done it. It's in the warm with no wind on a perfectly consistent surface and with perfectly consistent lighting. As a result, the use of statistics on lots and lots of shots tends to be the only real way to disentangle fact from mere happenstance. In the next post of this series, I'll talk about using SCATT to compare equipment, techniques and positions.
Friday, 5 June 2015
Interpreting SCATT results, Part 1 - Traces
To get the most out of a SCATT, it is valuable to learn how to interpret the various bits of information that it provides. The two key approaches that I have found useful when using a SCATT to analyse technique are interpretation the trace itself, and numerical analysis of some of the values that SCATT provides. These two approaches appear to be useful for different things and under different circumstances. Traces are the most immediate way of using your shooter training system to help you improve.
I find the traces themselves to be most useful in identifying and diagnosing gross or intermittent errors in technique; however it should be noted that not all errors always show up on SCATT (flinch or snatch being one of them) so it shouldn't be taken as read that a shooter with a perfect SCATT trace doesn't have any other issues. Trace analysis is less useful in refinement of an already good technique or in comparing two positions, techniques or items of equipment.
Interpretation of Traces
SCATTs and other shooter training systems record where the rifle is pointing through the shot sequence as a coloured line on the target diagram. This is generally called the trace.
The trace can be replayed by hitting the "Replay" button in the top left of the shot list pane. This will show the sequence of colours. The default settings for SCATT are as follows*:
Big / Obvious Things
Poor Hold - In the image below you can see that the trace is just really big. This is the kind of thing you see with beginners. Seeing it is easy, knowing what to do about it is harder, as it can be a lot of things. Look at jacket fit, sling tension and arm tension for starters.
Pointing Errors - If you don't point the thing in the middle then the shot doesn't go there. If the trace length and the shot release are OK, but the shot is out of the group then you probably just pointed the rifle badly. Make sure that you're centring the target correctly in the foresight and the foresight in the rearsight. If you think you're OK on these fronts and you've not had one done recently, go get an eye test. I used to use Stewards of Bisley and always found them perfectly acceptable, but swapped to Gary Alexander a few years ago as it was more convenient and the craic is better.
Snatch / Twitch / Flinch - The movement of the rifle sped up just as the shot broke and the shot got "flung" quite a way from the centre of the hold. This sudden, rapid motion is usually caused by flinch, snatch, a muscular twitch. The shooter needs to work on not anticipating the shot.
Wander - If the rifle consistently wanders left or right as you pull the trigger, then you're probably not pulling it straight or your NPA isn't aligned with the centre of the target. To test if it's trigger pull, take the first stage of the trigger and release it while watching the screen. If the rifle moves back and forth, you're not pulling the trigger straight.
Littler Things
Heartbeats - Heartbeats show up as loops or kinks in the trace at regular intervals. Don't worry about these as there's pretty much nothing you can do about them; although you will find that with practice you can lower your heartbeat when you're about to shoot. Shooting at the natural respiratory pause helps also.
Kinks - If your trace is kinky or spiky then there's unwanted muscle tension, which probably isn't helping. Make sure that you're relaxing your left arm and right shoulder completely. The rifle should naturally want to point at the middle of the target (see The Magic Bullet Magnet Theory) so there should be no need to muscle it into position. If you're also dropping the occasional shot low, then you may be holding the rifle up on the target. Check your sling is tight enough, your sling isn't slipping down your left arm, and that you're jacket is a tight enough fit.
Spikes - Every so often something really odd will happen and you'll get a massively flung shot. The trace may look OK, but the purple splotch may be miles away from the trace; or the trace has an enormous spike in it and the shot is well out in the magpie, outer or worse. There seem to be two causes for this: the most likely one is interference from lighting or strong heat source. Occasionally though, the plastic grommet which holds the lens in the front of the optical sensor can work loose. Once you've eliminated lighting and strong heat sources as an issue, the easiest way to test for this is to clamp the rifle in a workbench and fire a couple of shots at the target very carefully.
Finally, some caveats: there are several schools of thought on how to do this and these are only my ideas and what I have found to be useful. Other people think differently, so it's really worth reading around the subject; however there doesn't seem to be a huge amount available. I am still developing my expertise, so please don't think of this article as the be-all or the end-all; it's really just a primer.
*These can be modified through the "shot parameters" and "options" entries in the "Tools" menu. If something looks a little weird then it may be worth checking these haven't been modified.
I find the traces themselves to be most useful in identifying and diagnosing gross or intermittent errors in technique; however it should be noted that not all errors always show up on SCATT (flinch or snatch being one of them) so it shouldn't be taken as read that a shooter with a perfect SCATT trace doesn't have any other issues. Trace analysis is less useful in refinement of an already good technique or in comparing two positions, techniques or items of equipment.
Interpretation of Traces
SCATTs and other shooter training systems record where the rifle is pointing through the shot sequence as a coloured line on the target diagram. This is generally called the trace.
 |
| The trace is made up of the green, yellow, blue/grey and red lines superimposed over the target. The shot is represented by the purple circle. Image has been edited to reduce the amount of whitespace. |
- Start of trace until last 1 second - GREEN
- Last 1 sec - YELLOW
- Last 0.2 sec - BLUE/GREY
- Follow-through - RED
Big / Obvious Things
Poor Hold - In the image below you can see that the trace is just really big. This is the kind of thing you see with beginners. Seeing it is easy, knowing what to do about it is harder, as it can be a lot of things. Look at jacket fit, sling tension and arm tension for starters.
 |
| In out, in out, shake it all about. |
Pointing Errors - If you don't point the thing in the middle then the shot doesn't go there. If the trace length and the shot release are OK, but the shot is out of the group then you probably just pointed the rifle badly. Make sure that you're centring the target correctly in the foresight and the foresight in the rearsight. If you think you're OK on these fronts and you've not had one done recently, go get an eye test. I used to use Stewards of Bisley and always found them perfectly acceptable, but swapped to Gary Alexander a few years ago as it was more convenient and the craic is better.
 |
| A really nice group spoiled by one high left shot. From the trace it was clear that it was just aimed in the wrong place; the trace length, shot release and shape of the trace were all fine. |
Snatch / Twitch / Flinch - The movement of the rifle sped up just as the shot broke and the shot got "flung" quite a way from the centre of the hold. This sudden, rapid motion is usually caused by flinch, snatch, a muscular twitch. The shooter needs to work on not anticipating the shot.
 |
| Whoops, that one got away from me. Aim and hold aren't bad though. |
Wander - If the rifle consistently wanders left or right as you pull the trigger, then you're probably not pulling it straight or your NPA isn't aligned with the centre of the target. To test if it's trigger pull, take the first stage of the trigger and release it while watching the screen. If the rifle moves back and forth, you're not pulling the trigger straight.
 |
| The aim drifts in from the far upper left quadrant of the bullseye. This was the first in a string of otherwise good shots centred high and left, so could have been skew-whiff trigger pull. |
Littler Things
Heartbeats - Heartbeats show up as loops or kinks in the trace at regular intervals. Don't worry about these as there's pretty much nothing you can do about them; although you will find that with practice you can lower your heartbeat when you're about to shoot. Shooting at the natural respiratory pause helps also.
 |
| The little loops with the blue rings (added by me using paint) around them are the result of heartbeats. |
Kinks - If your trace is kinky or spiky then there's unwanted muscle tension, which probably isn't helping. Make sure that you're relaxing your left arm and right shoulder completely. The rifle should naturally want to point at the middle of the target (see The Magic Bullet Magnet Theory) so there should be no need to muscle it into position. If you're also dropping the occasional shot low, then you may be holding the rifle up on the target. Check your sling is tight enough, your sling isn't slipping down your left arm, and that you're jacket is a tight enough fit.
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| The hold is good and the result excellent, but the spikes that can be seen in the green trace rising up towards the bullseye as the shooter exhales are the result of muscular tension in the left upper arm or the right shoulder. |
Spikes - Every so often something really odd will happen and you'll get a massively flung shot. The trace may look OK, but the purple splotch may be miles away from the trace; or the trace has an enormous spike in it and the shot is well out in the magpie, outer or worse. There seem to be two causes for this: the most likely one is interference from lighting or strong heat source. Occasionally though, the plastic grommet which holds the lens in the front of the optical sensor can work loose. Once you've eliminated lighting and strong heat sources as an issue, the easiest way to test for this is to clamp the rifle in a workbench and fire a couple of shots at the target very carefully.
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| Massive, unexplained spike. This may be the result of a really bad shot or infrared lighting interference, but occasionally can be the result of the plastic grommet which holds the lens in place in the optical sensor loosening and allowing the lens to move. Please Note - Image doctored to show the effect, as I couldn't find one in my SCATT files. |
Finally, some caveats: there are several schools of thought on how to do this and these are only my ideas and what I have found to be useful. Other people think differently, so it's really worth reading around the subject; however there doesn't seem to be a huge amount available. I am still developing my expertise, so please don't think of this article as the be-all or the end-all; it's really just a primer.
*These can be modified through the "shot parameters" and "options" entries in the "Tools" menu. If something looks a little weird then it may be worth checking these haven't been modified.