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<blockquote data-quote="Dave King" data-source="post: 40961" data-attributes="member: 3"><p>Cant Error:</p><p></p><p> There is a thread on this site about this.</p><p> <a href="http://www.longrangehunting.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001300" target="_blank">http://www.longrangehunting.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001300</a> </p><p></p><p> Cant is often an unseen problem. The shooter is on a side hill, shooting across or onto other non-uniform terrain. I can easily imagine cant erros of several degrees and values of the stated six (6) degrees don't seem unlikely.</p><p></p><p> As I understand it, Cant induced error, unlike inclined fire error is more significant in the smaller (initial) angles. A six (6) degree inclined fire deviation factor (cosine) would be .005 while the cant deviation factor would be .104. </p><p></p><p> 500 yards... I'll just pick number for elevation (doesn't matter the number I pick, someone will make something of it other than offered anyway). 12 MOA of elevation required for a 500 yard shot. Add this to the elevation required to get to to 100 yard zero, ~ 3 MOA and we get a total of 15 MOA elevation, this amount to 15*5*1.044 and we get 78 inches of total drop.</p><p></p><p> Now, shoot on a 6 degree incline and get use 78 * .005 = .39 inches of POA to POI error.</p><p></p><p> Cant the rifle over 6 degrees (assume we're shooting in a no-wind condition so no windage on the scope) and we'll get 78 * .104 = 8.1 inches of POA to POI error.</p><p></p><p> <UL TYPE=SQUARE>POA to POI error for 78 inches of elevation</p><p>and the indicated angle.</p><p></p><p>Error in inches</p><p>Columns are</p><p></p><p>Canted</p><p></p><p>Inclined</p><p></p><p>Angle</p><p></p><p>Cant Incl Angle in degrees</p><p>1.36 0.01 1</p><p>2.72 0.04 2</p><p>4.08 0.10 3</p><p>5.44 0.19 4</p><p>6.79 0.29 5</p><p>8.15 0.42 6</p><p>9.50 0.58 7</p><p>10.8 0.75 8</p><p>12.2 0.96 9</p><p>13.5 1.18 10</p><p>14.8 1.43 11</p><p>16.2 1.70 12</p><p>17.5 1.99 13</p><p>18.8 2.31 14</p><p>20.1 2.65 15</p><p>21.4 3.02 16</p><p>22.8 3.40 17</p><p>24.1 3.81 18</p><p>25.3 4.24 19</p><p>26.6 4.70 20</p><p>27.9 5.18 21</p><p>29.2 5.67 22</p><p>30.4 6.20 23</p><p>31.7 6.74 24</p><p>32.9 7.30 25</p><p>34.1 7.89 26</p><p>35.4 8.50 27</p><p>36.6 9.13 28</p><p>37.8 9.77 29</p><p>39.0 10.4 30</p><p>40.1 11.1 31</p><p>41.3 11.8 32</p><p>42.4 12.5 33</p><p>43.6 13.3 34</p><p>44.7 14.1 35</p><p>45.8 14.8 36</p><p>46.9 15.7 37</p><p>48.0 16.5 38</p><p>49.0 17.3 39</p><p>50.1 18.2 40</p><p>51.1 19.1 41</p><p>52.1 20.0 42</p><p>53.1 20.9 43</p><p>54.1 21.8 44</p><p>55.1 22.8 45</p><p>56.1 23.8 46</p><p>57.0 24.8 47</p><p>57.9 25.8 48</p><p>58.8 26.8 49</p><p>59.7 27.8 50</p><p>60.6 28.9 51</p><p>61.4 29.9 52</p><p>62.2 31.0 53</p><p>63.1 32.1 54</p><p>63.8 33.2 55</p><p>64.6 34.3 56</p><p>65.4 35.5 57</p><p>66.1 36.6 58</p><p>66.8 37.8 59</p><p>67.5 39.0 60</p><p>68.2 40.1 61</p><p>68.8 41.3 62</p><p>69.4 42.5 63</p><p>70.1 43.8 64</p><p>70.6 45.0 65</p><p>71.2 46.2 66</p><p>71.7 47.5 67</p><p>72.3 48.7 68</p><p>72.8 50.0 69</p><p>73.2 51.3 70</p><p>73.7 52.6 71</p><p>74.1 53.8 72</p><p>74.5 55.1 73</p><p>74.9 56.5 74</p><p>75.3 57.8 75</p><p>75.6 59.1 76</p><p>76.0 60.4 77</p><p>76.2 61.7 78</p><p>76.5 63.1 79</p><p>76.8 64.4 80</p><p>77.0 65.7 81</p><p>77.2 67.1 82</p><p>77.4 68.4 83</p><p>77.5 69.8 84</p><p>77.7 71.2 85</p><p>77.8 72.5 86</p><p>77.8 73.9 87</p><p>77.9 75.2 88</p><p>77.9 76.6 89</p><p>78.0 78.0 90</p><p></p><p> [/list]</p><p></p><p>My out: This is as I understand these issues, it may or may not be the truth. I choose to believe this is the manner in which this happens based on several tests at 100 yards.</p><p></p><p><strong><em>Maybe we can get one of our real ballistic guru's to add on here. I'm only posting based on what I've seen and tried and then tried to qualify and quantify. JBM, Warren Jensen, anyone... will a real ballistics guy please stand up </em></strong></p><p></p><p>[ 03-11-2004: Message edited by: Dave King ]</p></blockquote><p></p>
[QUOTE="Dave King, post: 40961, member: 3"] Cant Error: There is a thread on this site about this. [url="http://www.longrangehunting.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001300"]http://www.longrangehunting.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001300[/url] Cant is often an unseen problem. The shooter is on a side hill, shooting across or onto other non-uniform terrain. I can easily imagine cant erros of several degrees and values of the stated six (6) degrees don't seem unlikely. As I understand it, Cant induced error, unlike inclined fire error is more significant in the smaller (initial) angles. A six (6) degree inclined fire deviation factor (cosine) would be .005 while the cant deviation factor would be .104. 500 yards... I'll just pick number for elevation (doesn't matter the number I pick, someone will make something of it other than offered anyway). 12 MOA of elevation required for a 500 yard shot. Add this to the elevation required to get to to 100 yard zero, ~ 3 MOA and we get a total of 15 MOA elevation, this amount to 15*5*1.044 and we get 78 inches of total drop. Now, shoot on a 6 degree incline and get use 78 * .005 = .39 inches of POA to POI error. Cant the rifle over 6 degrees (assume we're shooting in a no-wind condition so no windage on the scope) and we'll get 78 * .104 = 8.1 inches of POA to POI error. <UL TYPE=SQUARE>POA to POI error for 78 inches of elevation and the indicated angle. Error in inches Columns are Canted Inclined Angle Cant Incl Angle in degrees 1.36 0.01 1 2.72 0.04 2 4.08 0.10 3 5.44 0.19 4 6.79 0.29 5 8.15 0.42 6 9.50 0.58 7 10.8 0.75 8 12.2 0.96 9 13.5 1.18 10 14.8 1.43 11 16.2 1.70 12 17.5 1.99 13 18.8 2.31 14 20.1 2.65 15 21.4 3.02 16 22.8 3.40 17 24.1 3.81 18 25.3 4.24 19 26.6 4.70 20 27.9 5.18 21 29.2 5.67 22 30.4 6.20 23 31.7 6.74 24 32.9 7.30 25 34.1 7.89 26 35.4 8.50 27 36.6 9.13 28 37.8 9.77 29 39.0 10.4 30 40.1 11.1 31 41.3 11.8 32 42.4 12.5 33 43.6 13.3 34 44.7 14.1 35 45.8 14.8 36 46.9 15.7 37 48.0 16.5 38 49.0 17.3 39 50.1 18.2 40 51.1 19.1 41 52.1 20.0 42 53.1 20.9 43 54.1 21.8 44 55.1 22.8 45 56.1 23.8 46 57.0 24.8 47 57.9 25.8 48 58.8 26.8 49 59.7 27.8 50 60.6 28.9 51 61.4 29.9 52 62.2 31.0 53 63.1 32.1 54 63.8 33.2 55 64.6 34.3 56 65.4 35.5 57 66.1 36.6 58 66.8 37.8 59 67.5 39.0 60 68.2 40.1 61 68.8 41.3 62 69.4 42.5 63 70.1 43.8 64 70.6 45.0 65 71.2 46.2 66 71.7 47.5 67 72.3 48.7 68 72.8 50.0 69 73.2 51.3 70 73.7 52.6 71 74.1 53.8 72 74.5 55.1 73 74.9 56.5 74 75.3 57.8 75 75.6 59.1 76 76.0 60.4 77 76.2 61.7 78 76.5 63.1 79 76.8 64.4 80 77.0 65.7 81 77.2 67.1 82 77.4 68.4 83 77.5 69.8 84 77.7 71.2 85 77.8 72.5 86 77.8 73.9 87 77.9 75.2 88 77.9 76.6 89 78.0 78.0 90 [/list] My out: This is as I understand these issues, it may or may not be the truth. I choose to believe this is the manner in which this happens based on several tests at 100 yards. [B][I]Maybe we can get one of our real ballistic guru's to add on here. I'm only posting based on what I've seen and tried and then tried to qualify and quantify. JBM, Warren Jensen, anyone... will a real ballistics guy please stand up [/I][/B][I][/I] [ 03-11-2004: Message edited by: Dave King ] [/QUOTE]
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