zigliss Posted July 13, 2009 Report Share Posted July 13, 2009 Folks - just need a bit of help checking my thinking here. I am working up a chart to calculate number of clicks required for a 4-24x50 Ior mounted on a 20MOA rail zeroed at 100 yards reaching out to 1000yards. Here are the important bits: - Scope clicks - 1/4 MoA - Rail - 20MOA - 100 yard zero - 139gr Lapua Scenar - BC 0.615 - Velocity - 2700 fps From a 100 yard zero I calulate, off a 20MOA, rail that I need just over 12Moa (32 without the rail) at 1000 yards or 48 clicks on the turret. Does this sound correct to you? Link to comment Share on other sites More sharing options...
1967spud Posted July 13, 2009 Report Share Posted July 13, 2009 can you please tell me what calibre and what height scope is above centre of bore at the reticles please then ill run it through exbal for you, if you want that is Link to comment Share on other sites More sharing options...
zigliss Posted July 13, 2009 Author Report Share Posted July 13, 2009 can you please tell me what calibre and what height scope is above centre of bore at the reticles please then ill run it through exbal for you, if you want that is Cheers Mark: 6.5mm and 2 inches. Link to comment Share on other sites More sharing options...
eldon Posted July 13, 2009 Report Share Posted July 13, 2009 If your working from a 100 yd zero (reference point) and it takes 12 moa for example to get to x yds then the 20 moa rail makes no difference and is a side issue The calibre if it needs x moa to reach say 1000 yds will still need the same x moa due to the laws of physics. The bit where you say 32 now becomes 12 moa can't be right can it ? Otherwise if you put a 32 moa rail on then the 100 yds and 1000yds zero's would be the same The advantage of the 20 moa rail is that there is more adjustment left in your scope assuming you can get down as far as 100 yds to zero. Therefore enabling the set up to reach further by dialing without using holdover. Basically you are maximising the available scope adjustment. Link to comment Share on other sites More sharing options...
zigliss Posted July 13, 2009 Author Report Share Posted July 13, 2009 If your working from a 100 yd zero (reference point) and it takes 12 moa for example to get to x yds then the 20 moa rail makes no difference and is a side issue The calibre if it needs x moa to reach say 1000 yds will still need the same x moa due to the laws of physics. The bit where you say 32 now becomes 12 moa can't be right can it ? Otherwise if you put a 32 moa rail on then the 100 yds and 1000yds zero's would be the same The advantage of the 20 moa rail is that there is more adjustment left in your scope assuming you can get down as far as 100 yds to zero. Therefore enabling the set up to reach further by dialing without using holdover. Basically you are maximising the available scope adjustment. Thanks Eldon - realised my 'Doh' moment a few mins after I wrote the post. Having zeroed with the rail on it doesn't make any difference. Mark is checking my calcs through Exbal in any case. Link to comment Share on other sites More sharing options...
1967spud Posted July 13, 2009 Report Share Posted July 13, 2009 Cheers Mark: 6.5mm and 2 inches. 6.5 what? Link to comment Share on other sites More sharing options...
1967spud Posted July 13, 2009 Report Share Posted July 13, 2009 EXAMPLE 308 Win : Lapua Bullets 0.264" 139gr Scenar SIGHT IN FIELD DATA DATA POINT BLANK RANGE DATA MUZZLE VELOCITY (fps) 2700 2700 TARGET SIGHT-IN HIGH LOW BULLET WEIGHT (grains) 139 HEIGHT DISTANCE POINT POINT SIGHT HT ABOVE BORE (in) 2 (in) (yd) (yd) (yd) SIGHT IN DISTANCE (yd) 100 2 169 108 193 ALTITUDE (ft) 0 0 4 209 124 242 TEMPERATURE (deg F) 59 59 6 241 138 281 PRESSURE @ SEA LEVEL (in Hg) 29.53 29.53 8 268 151 314 PRESSURE @ ALTITUDE (in Hg) 29.53 29.53 10 292 162 343 RELATIVE HUMIDITY (pct) 78 78 WIND VELOCITY (mph) 10 WIND ANGLE (deg) 90 ( 3.0 O'Clock) INCLINE ANGLE (deg) 0 MAX APPARENT TRAJECTORY (in) 0 BALLISTIC COEFF 0.615 Sight Adjustments Needed Trajectory Values 1 MPH Drop From Time of RANGE Elevation Windage Tgt Lead Elevation Wind Drift Tgt Lead Velocity Energy Bore Line Flight (yd) MOA MOA MOA (in) (in) (in) (fps) (ft-lb) (in) (sec) 0 0.00 0.00 0.00 -2.0 0.0 0.0 2700 2250 0.0 0.0000 25 4.00 0.00 2.00 -1.0 0.0 0.5 2663 2189 -0.1 0.0280 50 0.75 0.25 2.00 -0.4 -0.1 1.0 2627 2129 -0.6 0.0563 75 0.00 0.50 2.00 0.0 -0.3 1.5 2591 2071 -1.4 0.0851 100 0.00 0.50 2.00 0.0 -0.5 2.0 2555 2014 -2.5 0.1142 125 0.25 0.75 2.00 -0.3 -0.9 2.5 2519 1958 -3.9 0.1438 150 0.50 0.75 2.00 -1.0 -1.2 3.1 2484 1904 -5.6 0.1737 175 1.00 1.00 2.00 -2.0 -1.7 3.6 2449 1850 -7.8 0.2041 200 1.50 1.00 2.00 -3.3 -2.2 4.1 2414 1798 -10.2 0.2350 225 2.25 1.25 2.00 -5.1 -2.9 4.7 2379 1747 -13.1 0.2663 250 2.75 1.25 2.00 -7.2 -3.6 5.2 2345 1697 -16.3 0.2980 275 3.25 1.50 2.00 -9.7 -4.3 5.8 2311 1648 -19.9 0.3302 300 4.00 1.75 2.00 -12.6 -5.2 6.4 2277 1600 -24.0 0.3629 325 4.75 1.75 2.00 -16.0 -6.2 7.0 2244 1554 -28.4 0.3961 350 5.50 2.00 2.00 -19.7 -7.2 7.6 2211 1508 -33.3 0.4297 375 6.00 2.00 2.00 -24.0 -8.3 8.2 2178 1464 -38.6 0.4639 400 6.75 2.25 2.00 -28.6 -9.5 8.8 2146 1421 -44.4 0.4986 425 7.50 2.50 2.00 -33.8 -10.8 9.4 2114 1378 -50.7 0.5338 450 8.25 2.50 2.25 -39.4 -12.2 10.0 2082 1337 -57.4 0.5695 475 9.25 2.75 2.25 -45.5 -13.7 10.7 2050 1297 -64.7 0.6058 500 10.00 3.00 2.25 -52.2 -15.3 11.3 2019 1258 -72.4 0.6427 525 10.75 3.00 2.25 -59.4 -17.0 12.0 1988 1219 -80.7 0.6801 550 11.75 3.25 2.25 -67.1 -18.8 12.6 1957 1182 -89.6 0.7181 575 12.50 3.50 2.25 -75.4 -20.7 13.3 1927 1145 -99.0 0.7568 600 13.50 3.50 2.25 -84.3 -22.8 14.0 1896 1110 -109.0 0.7960 625 14.25 3.75 2.25 -93.8 -24.9 14.7 1867 1075 -119.6 0.8358 650 15.25 4.00 2.25 -103.9 -27.1 15.4 1837 1041 -130.8 0.8763 675 16.25 4.25 2.25 -114.6 -29.5 16.2 1808 1008 -142.6 0.9175 700 17.25 4.25 2.25 -126.0 -32.0 16.9 1779 976 -155.2 0.9593 725 18.25 4.50 2.25 -138.1 -34.5 17.6 1750 945 -168.4 1.0018 750 19.25 4.75 2.25 -151.0 -37.3 18.4 1722 915 -182.3 1.0450 775 20.25 5.00 2.25 -164.5 -40.1 19.2 1693 885 -197.0 1.0889 800 21.25 5.25 2.50 -178.8 -43.1 20.0 1666 856 -212.4 1.1336 825 22.50 5.25 2.50 -193.9 -46.2 20.8 1639 828 -228.6 1.1789 850 23.50 5.50 2.50 -209.8 -49.4 21.6 1612 802 -245.6 1.2251 875 24.75 5.75 2.50 -226.5 -52.8 22.4 1586 776 -263.4 1.2720 900 26.00 6.00 2.50 -244.1 -56.3 23.2 1560 751 -282.1 1.3197 925 27.00 6.25 2.50 -262.6 -59.9 24.1 1534 726 -301.7 1.3682 950 28.25 6.50 2.50 -282.0 -63.7 25.0 1509 703 -322.2 1.4175 975 29.50 6.50 2.50 -302.4 -67.6 25.8 1485 680 -343.7 1.4676 1000 31.00 6.75 2.50 -323.7 -71.7 26.7 1461 658 -366.2 1.5185 Link to comment Share on other sites More sharing options...
1967spud Posted July 13, 2009 Report Share Posted July 13, 2009 this may be better for you Link to comment Share on other sites More sharing options...
zigliss Posted July 13, 2009 Author Report Share Posted July 13, 2009 Great - thanks Mark - I had 31.8 MOA throuhg the programme I was using so close enough! Link to comment Share on other sites More sharing options...
Guest varmartin Posted July 13, 2009 Report Share Posted July 13, 2009 Her is my take on it .......... All you need to know is ....BC....Velocity ...sight adjustment specs...zero point and scope height......for a drop chart !! It does not matter what calibre, case, bullet weight , bore size, scope base ...........etc etc Then fine tune it with the ` field and range conditions ...ie, temp, alt, relative humidity and pressure ...... Link to comment Share on other sites More sharing options...
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