Ballistic Ratio

[CurtB]

How can I figure out the correct setting is for my discipline? I’m shooting a 1000yd target with 155gr bullets at 3100ft/sec.

 

[Peter]

How can I figure out the correct setting is for my discipline? I’m shooting a 1000yd target with 155gr bullets at 3100ft/sec.

Ballistic Ratio's value varies from gun to gun and depends on a bunch of factors (gun's barrel, ammo quality, bullet speed, etc.)
Hence, you can't simply copy-paste the ratio of your shooter peers at the range.

That's why in order to find your personalized Ballistic Ratio, we highly recommend shooting a group of 10 (at least, but the more - the better) live shots with SCATT and comparing both groups (real shot-holes vs. what SCATT displays). When this is done feel free to start adjusting the Ratio back and forth in the settings until both groups look almost identical. After the optimal value for the gun and particular event is established - it would be a good idea to write it down in case you happen to switch laptops (so you won't have to go through this calibration again).

Also, you don't really have to bring your SCATT and laptop to the range with you (although that would be ideal), since every shooter is more or less consistent from series to series. Thus, you can simply take the cards with you after you are done shooting live rounds for the day and adjust your coefficient in the comfort of your home. Here is another little tip in case you've been fidgeting with coefficient values and now would like to go back to default settings, yet forgot what it was set to initially: just create a new user and start an event - this shall effectively reset the settings in regards to your Ballistic Ratio.

It's crucial to understand that the shot holes will most likely not match 100%, as any SCATT model is a training tool first and foremost and should not be used as a substitute for an electronic scoring system. Generally speaking, SCATT is really good at predicting where the bullet should go, but it can't take into account that say, bullet number 8 is going to be flawed and won't go where a perfectly-manufactured bullet should go.

In a nutshell, even if the Ballistic Ratio you arrive at doesn't yield identical shot holes - it's OK and you shouldn't get discouraged, for it would be a good idea to analyze the shots that don't quite match the real shot-holes. This discrepancy may be in fact indicating that you have too much trigger-jerk during the last 250 milliseconds of the shot. So your hand flinches and gives the bullet enough sideways momentum that it flyes and curves away from the software-predicted trajectory. In this case, I'd highly recommend taking a closer look at how you are operating the gun in regards to those particular shots (S1 vs. S2 dynamic in the stat-table).

 

[CurtB]

Thank you.

 

[CharlesD]

Ballistic Ratio's value varies from gun to gun and depends on a bunch of factors (gun's barrel, ammo quality, bullet speed, etc.)
Hence, you can't simply copy-paste the ratio of your shooter peers at the range.

That's why in order to find your personalized Ballistic Ratio, we highly recommend shooting a group of 10 (at least, but the more - the better) live shots with SCATT and comparing both groups (real shot-holes vs. what SCATT displays). When this is done feel free to start adjusting the Ratio back and forth in the settings until both groups look almost identical. After the optimal value for the gun and particular exercise is established - it would be a good idea to write it down in case you happen to switch laptops (so you won't have to go through this calibration again).

CurtB - This is certainly the way to go to determine the best Ballistic Ratio (F Coefficient for those of us with older Scatt systems). However, it depends on two things: You need a live fire Scatt system (MX--) and you need to be shooting in an environment where wind has minimal effect (indoors or at short range). Fullbore shooters in Commonwealth countries generally shoot at distances of 300-1000 yds (300-900m). US High-Power shooters spend most of their time at 1000 yds. This Ballistic Ratio test might work at 300 yds/m on a relatively calm day, but you will need a very calm day to do a comparison at any longer distance.
Furthermore, friends who have tried live fire Scatt at fullbore targets have generally been unsuccessful in getting the sensor to recognise the target. This may be due to the relatively small area of white surrounding the aiming mark (the background beyond the edges of the target is usually a brown sand stop-butt) and/or the proximity of adjacent targets on the range (we rarely get the opportunity to shoot with just one target displayed). If the Scatt sensor had a narrower field of view it might help it to recognise the target. At 1000 yds the aiming mark is 44" (4.2 MOA) on a 72" (6.9 MOA) square white target (US dimensions - UK & Canada use a 48" (4.6 MOA) diameter aiming mark on a target that is the same height but slightly wider - 96" in Canada and 120" in the UK). As you can see, it needs a very narrow field of view sensor to recognise this as a target, hence the problem, even if you have a live fire Scatt (which most fullbore shooters in the UK don't - we bought ours before the MX versions became available).
In the absence of an ability to determine a more appropriate Ballistic Ratio value, we use 40, which seems to give about the right results. However, as Scatt is mainly used as a training aid, the precise value is of limited importance, provided we stick to the same value for all our sessions (to enable performance over time to be monitored). Furthermore, as we mostly use similar ammunition (7.62mm/.308" and 155 grain bullets) in similar rifles, if we all use the same Ballistic Ratio (F Coefficient), then we can compare our Scatt results directly with each other.

 

[Livold]

Ballistic Ratio's value varies from gun to gun and depends on a bunch of factors (gun's barrel, ammo quality, bullet speed, etc.)
Hence, you can't simply copy-paste the ratio of your shooter peers at the range.

That's why in order to find your personalized Ballistic Ratio, we highly recommend shooting a group of 10 (at least, but the more - the better) live shots with SCATT and comparing both groups (real shot-holes vs. what SCATT displays). When this is done feel free to start adjusting the Ratio back and forth in the settings until both groups look almost identical. After the optimal value for the gun and particular exercise is established - it would be a good idea to write it down in case you happen to switch laptops (so you won't have to go through this calibration again).

Also, you don't really have to bring your SCATT and laptop to the range with you (although that would be ideal), since every shooter is more or less consistent from series to series. Thus, you can simply take the cards with you after you are done shooting live rounds for the day and adjust your coefficient in the comfort of your home. Here is another little tip in case you've been fidgeting with coefficient values and now would like to go back to default settings, yet forgot what it was set to initially: just create a new user and start an event - this shall effectively reset the settings in regards to your Ballistic Ratio.

It's crucial to understand that the shot holes will most likely not match 100%, as any SCATT model is a training tool first and foremost and should not be used as a substitute for an electronic scoring system. Generally speaking, SCATT is really good at predicting where the bullet should go, but it can't take into account that say, bullet number 8 is going to be flawed and won't go where a perfectly-manufactured bullet should go.

In a nutshell, even if the Ballistic Ratio you arrive at doesn't yield identical shot holes - it's OK and you shouldn't get discouraged, for it would be a good idea to analyze the shots that don't quite match the real shot-holes. This discrepancy may be in fact indicating that you have too much trigger-jerk during the last 250 milliseconds of the shot. So your hand flinches and gives the bullet enough sideways momentum that it flyes and curves away from the software-predicted trajectory. In this case, I'd highly recommend taking a closer look at how you are operating the gun in regards to those particular shots (S1 vs. S2 dynamic in the stat-table).

Hello!
Can you tell if the F- Cofficient shall be at same level when shooting sharp on scatt and if dry firing ( click) on scatt? And in case what is normal here on 10m and 50m? Thank you!

 

[Peter]

Hello!
Can you tell if the F- Cofficient shall be at same level when shooting sharp on scatt and if dry firing ( click) on scatt? And in case what is normal here on 10m and 50m? Thank you!

You basically go through a live fire session in order to determine your personal F with that gun and then apply it to your dry-fire training as well as to all live-fire sessions that follow. So it should be the same

The defaults (a.k.a. what's normal) are already set for all disciplines in the software

 

[Livold]

You basically go through a live fire session in order to determine your personal F with that gun and then apply it to your dry-fire training as well as to all live-fire sessions that follow. So it should be the same

The defaults (a.k.a. what's normal) are already set for all disciplines in the software

Thank! How can you determine your spes F? You mean if monitor ( live fire) and scatt pc show about same groups?

 

[Peter]

Thank! How can you determine your spes F? You mean if monitor ( live fire) and scatt pc show about same groups?

Yes, the whole guide is there if you scroll a couple of messages up. "We highly recommend shooting a group of 10 (at least, but the more - the better) live shots with SCATT and comparing both groups (real shot-holes vs. what SCATT displays). When this is done feel free to start adjusting the Ratio back and forth in the settings until both groups look almost identical." So when the groups are almost identical you take that coefficient, let's say 41, and use it onward with that gun in that particular discipline (be it dry or live fire alike).

If you switch to another gun or another target/distance, this coefficient won't apply there - you'll need to go through the process again

 

[Bono760]

Hello Peter
Do you know the value of the ballistic ratio in the Scatt Basic ?
Thx

 

[Peter]

Do you know the value of the ballistic ratio in the Scatt Basic ?

My apologies for a delayed reply, this thread hasn't notified me of a new post for some reason
SCATT Basic has no F/Ballistic Ratio feature whatsoever so it's effectively set to 0
Therefore, you get absolutely no bullet drop/group dispersion. In other words, your shot-holes are exactly where you pulled the trigger.

 

[Highpower]

Also, you don't really have to bring your SCATT and laptop to the range with you (although that would be ideal), since every shooter is more or less consistent from series to series. Thus, you can simply take the cards with you after you are done shooting live rounds for the day and adjust your coefficient in the comfort of your home.

Peter, can you explain this part further. I don't understand how the coefficient can be determined based on live-fire targets if the SCATT was not used during the live-fire.

 

[Peter]

I don't understand how the coefficient can be determined based on live-fire targets if the SCATT was not used during the live-fire.

I mean, it's far easier to do this on the spot with your SCATT.
However, if that's not an option for some reason, you can shoot your average card, then take it back home and compare the group with what digital group the software shows when this or that Ballistic Ratio is picked.

Let's say this group with Ratio set to 14 looks almost identical to what your physical card shows
Then your optimal Ratio is 14 for this rifle/ammo/event

 

[Davidf92]

After the optimal value for the gun and particular exercise is established - it would be a good idea to write it down in case you happen to switch laptops

Hi Peter,
While understanding what the whole thing means, I still think there is no such thing as a perfect or even "optimal" coeff, simply because as you write it yourself all over the forum Scatt is not a shooting simulator supposed to perfectly reproduce real shooting. Looking for such optimal value is hardly more than purposeless.
Many shooters, more often long-range, also described that precise high values didn't make any discernable difference. Quite understandably the difference between 90 and 91 for instance will be far less in effect than between 4 and 5.

Besides, the way this coefficient is presented in Scatt's user manuals is more oriented at finding this supposed good value than correctly explaining what it means, and your answers such as the one I quoted above tend to make Scatt users anxious about having or not found their correct setting.

Quite on the contrary this coefficient is a very good tool when seen as Scatt's training support. A forum member very recently described the interest of setting the F-coefficient to the maximum, in order to "penalize"(sic) a variety of errors and facilitate analysis. You can also set it to zero and and precisely visualize aspects of your technical progression along the time, without the gun/ammo/environment interference.

In short it is not such a big deal and I am sorry most discussion about this question is globally misleading.

P.S. why not "set default" and "reset default" parameter buttons, instead of having to back up your value or cumbersomely search for the built-in default when needed?

 

[Old Lefty]

Presumably the F coefficient is supposed to simulate the fact that there are variations in the performance of bullets in a batch. This we know from batch testing. Does the F coefficient work on a random factor or is it more consistent? What I mean by that is the a bad round doesn't necessarily result in a poor shot. Logically a badly aimed shot might well be improved by a bad round. When F is set to zero Scatt will show exactly where the shooter aimed. An F of 30 will make the same series of shots worse and an F of 60 considerably worse. Which of these settings will be the best for the shooter to understand what he's doing right and what he's doing wrong?

 

[CharlesD]

Presumably the F coefficient is supposed to simulate the fact that there are variations in the performance of bullets in a batch. This we know from batch testing. Does the F coefficient work on a random factor or is it more consistent? What I mean by that is the a bad round doesn't necessarily result in a poor shot. Logically a badly aimed shot might well be improved by a bad round. When F is set to zero Scatt will show exactly where the shooter aimed. An F of 30 will make the same series of shots worse and an F of 60 considerably worse. Which of these settings will be the best for the shooter to understand what he's doing right and what he's doing wrong?

Ballistic Ratio (F Coefficient for those of us with older Scatt systems) is primarily a determinant of how much the bullet gets 'thrown', in the direction the muzzle is moving at the instant of firing the shot, before impacting the target. The 'throw' depends primarily on the speed at which your aim point is moving across the target face and the direction it is travelling when the bullet exits the barrel. This gives the bullet a lateral and vertical velocity which moves it away from the point at which you were aiming when you fired (the point at which the trace changes from blue to red). If you set Ballistic Ratio/F Coefficient to zero, Scatt will not apply any 'throw' and your shot will appear at the point at which you were aiming when you fired the shot. The larger the value of Ballistic Ratio/F Coefficient you set (and the faster the muzzle movement), the further Scatt will 'throw' your shot. By setting the value high, you can 'punish' your aiming and triggering errors by making the shot 'throw' unrealistically large. For most smallbore and fullbore rifle use a value of 40 seems to be about right (and is the default setting for many selected targets). Note that the direction the shot is 'thrown' depends on the instantaneous direction your aim was moving when you fired, so is just as likely to get thrown towards the centre of the target as it is to be thrown away from the centre! This can therefore often improve the shot's estimated score rather than always making it worse.
The direction and speed of movement of your muzzle at the instant of firing is determined by a combination of how steady your aim is (how far and how fast the muzzle is wobbling) and how good your trigger release is (whether you are pulling your aim off as you release the trigger, or whether it is a gentle squeeze directly in line with the bore which does not disturb your aim at all).
With a correctly set Ballistic Ratio/F Coefficient, the estimated score that Scatt produces will be reasonably representative of the actual score you would have got. If Ballistic Ratio/F Coefficient is unrealistically small (especially if zero), it will simply indicate how good your aim was, and not the score you would have got. Similarly, if you set it too high, it will throw the shots unrealistically far from your aim point (though this 'punishing' of errors can help you to correct your faults and improve more quickly).
You should always try to use the same Ballistic Ratio/F Coefficient when practising with the same target, so that you can directly compare the values of the performance information (metrics) Scatt provides between different shoots/different dates. If everyone you know also uses the same target and the same Ballistic Ratio/F Coefficient, then you can directly compare your performance with theirs. The easiest is always to use the default value that Scatt sets, depending on the target you choose. Otherwise 40 seems to be a good compromise.
Note that Scatt allows you to see the effects of changing the Ballistic Ratio/F Coefficient when viewing a saved shoot. This will show you what various performance metrics (including the estimated score) would have been if you had used that value when you were shooting.

 

[Davidf92]

@Old Lefty : I am answering your post in the "Using different F values for dry-fire depending of training goals" thread where you also posted.

 

[Davidf92]

Worth adding, F (more generally Scatt) does not simulate ammunition-related shots dipersion. This means that you may not be able to have Scatt closely simulate your real targets, sometimes even by far. However this will be a useful indication that you have a high level of dispersion, which you could investigate. The main factor is ammunition badly fitting your barrel, in which case you could test alternative ammo. Less often is it due to barrel wear or other defects which would require testing by an expert.