The Current Data and Main Menu Panels

These two panels appear together:

The Current Data panel displays all the adjustable parameters; the program user can change the values of the displayed data so as to represent alternative shooting conditions. Whilst most of these parameters may be familiar terms, others will become clearer as the worked example is followed through: the few parameters which will be new to most people will be described later.

Notice that the program has already calculated that there are 307 pellets in the test cartridge and has displayed this in the bottom of the Current Data panel.

Below this, the Main Menu panel is used to compute the predicted performance, display results, load alternative datafiles, write new datafiles, and terminate the program.

Using the Main Menu to Predict Performance

The Main Menu options are activated by pressing the key letters shown highlighted in bright blue. Start by pressing G.

You now see a temporary panel at the bottom of the screen:

Within this panel you can see the program's progress as it calculates performance at increasing ranges, from the muzzle to 100m. The program is initially set to fire 500 shots at each range to calculate average performance. These calculations should take only a few seconds, depending on the speed of your computer. As this temporary bottom panel states, pressing any key will stop these calculations. Once these calculations are complete, the graphic results are displayed in colour.

Each run of the same data will produce subtly different results, so your graphs and results may be slightly different from these shown - this is normal.

The top panel shows the performance at all ranges up to 100m: 'Ph' means 'probability', so the three curves show probabilities of hit, birds 'bagged', and unretrieved hit birds. The centre panel shows the spread of ranges over which the quarry is shot (i.e. the 'ranging policy'), so 'f' refers to the weighting factor according to range. These two panels are combined (hence 'f Ph') to produce the bottom panel, so this data is the predicted outcome in the field. It is the relative areas under the graph lines of this bottom panel which gives the 'hit' and 'bagged' percentages displayed at the lower right-hand side. Also shown is the 'bagged per hit' rate to indicate the relative 'effectiveness' of the cartridge and shooting conditions. It is a good idea to write down these numbers for comparison with later predictions.

In the top panel, the curves rise from low values at short range, pass through their maximum at mid range, and then fall as the range becomes excessive. The low hit rate at short range is due to the difficulty of bringing the gun onto the bird quickly, and the fall in hit rate at extreme range is due to the combined effect of pellet dispersion and inadequate penetration by the slowing pellets.

Owing to the random-sampling nature of the numerical simulation, repeated computations with the same Current Data values will produce slightly differing results: a great number of shots would produce better consistency. In this example 500 shots are fired at each of 100 ranges, totalling 50,000 shots: by comparison, a game shooter may only fire a few hundred shots in a season, so it is not surprising that true in-the-field results are so variable!

… and so don't be surprised if your computed results differ slightly from these:

55%  Hit
43%  Bagged
77%  Bagged/Hit.

… and the result of just one day's shoot may be very different. Keep in mind that the program is predicting the average result across many shoots and many thousands of cartridges. Besides, the predictions are for single shots, whereas the shooter often has at least a second shot available, which will no doubt modify the overall outcome.

As indicated in bright blue at the lower right-hand corner of the screen, press any key to return the program to the Current Data and Main Menu panels.

The worked example shows that the predicted in-the-field outcome using No.6, 32 grams lead shot is 43% Bagged with a 77% Bagged/Hit rate. How does this compare with the No.6, 32grams 'steel' shot? For this we need to load data for the 'steel' shot.

Press I for the Input Menu, which is then displayed at the bottom of the screen.

A new cartridge load is needed, so press L to redisplay the selection of cartridges:

This time use the & keys to select the 32 gram, No 6 steel shot, and then press the (enter) key.

The Current Data panel reappears with the correct material density for steel (7.87 g/cc) and has already calculated that there are 442 pellets.

Press G (Graph) to calculate the performance with the steel shot cartridge and produce a graphed results similar to these:

Now the predicted performance of the steel shot can be compared with that for the lead shot.

This completes the first part of the worked example showing the value of this program in revealing the likely differences in performance between different loads.

Now, let's use the editing facilities to change some of the other parameters to see what might improve the performance of steel shot. Press any key to return to the Current Data panel.