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Posted: 7/3/2003 6:34:47 PM EDT
I currently have my EOTech 552 zeroed at 50 yds. When shooting upclose (@25 yds.) you aim about 3 inches high to hit your point. (This shows my ignorance) If zeroed at 25 yds. how would POA differ?

TS
Link Posted: 7/3/2003 6:59:05 PM EDT
You mean when you shoot point blank with a 25yrd zero? Or out to 50yrd with a 25yrd. zero. Sorry just need to make sure I know what you need!
Link Posted: 7/3/2003 9:10:46 PM EDT
Sorry, that was poorly worded and constructed. My EOTech currently zeroed at 50yds hits the a 25 yard target about three inches lower than the point of aim. Naturally if I zero the weapon at 25 it will hit the POA at 25. Where will the bullet hit at 50 yds if zeroed at 25? And where will it impact in realtion to point of aim at 100? Thanks, TS
Link Posted: 7/3/2003 9:58:40 PM EDT
[Last Edit: 7/3/2003 10:10:28 PM EDT by gman552]
I used this ballistic calculator [url]http://www.beartoothbullets.com/rescources/calculators/balistics/[/url] to calculate bullet drop/rise using a 55 gr FMJ bullet with a BC of 0.255, muzzle velocity of 3240 fps, and sight height of 2.6". With a 25-yd zero, you get the following: 00 yds, -2.6" 25 yds, 0" 50 yds, +2.4" 75 yds, +4.5" 100 yds, +6.4" 125 yds, +8.1" ... ... 250 yds, +11.5" ... ... 414 yds, 0" I just attended a CQB carbine class where we zeroed at 30 yds. The bullet would be +1.6" at 50 yds, +4.8" at 100 yds, +7.9" at 220 yds, and back to far zero at 364 yds. The [url=http://groups.msn.com/TheMarylandAR15ShootersSite/zeroingmethods.msnw]improved battlesight zero (IBSZ)[/url] gives a near zero of 50 yds and a far zero of 243 yds, with no more than -2.6" (muzzle) or +2.3" (150 yds) between these ranges. My question: Is there a different zeroing method for CQB weapons (100 yds or less)?
Link Posted: 7/3/2003 11:43:29 PM EDT
Thanks, Gman. I plan on shooting no farther than 150 yds with this particular weapon. TS
Link Posted: 7/17/2003 10:35:14 AM EDT
Then zero at 50 yards. Even for CQB zero at 50 yards. If you check the offsets at the closer zeros (say 25y or 30 y) you STILL have to adjust for headshots at 12 yards (or closer) - the difference isn't all that much. But you don't need it at 25y By zeroing at 50 yards its COM for body shots, and the holdover for head shots from say 8 yards to 25y is close enough that 1 hold over value value should work at all CQB distances. Plus you get that nice flat trajectory +/-2" out to 220y for the longer shots.
Link Posted: 7/17/2003 11:44:17 PM EDT
Thanks for the real life reasoning and practical necessity for the 50yd zero. TS
Link Posted: 7/18/2003 12:13:13 AM EDT
[Last Edit: 7/18/2003 12:20:45 AM EDT by bvmjethead]
Input Data @ 25 yard zero Muzzle Velocity: 3240.0 ft/sec Chronograph Distance: 10.000 feet Ballistic Coefficient: 0.255 Drag Function: G1 Bullet Weight: 55 grains Sight Height: 2.60 inches Sight Offset: 0.00 inches Wind Range Speed: 0 mph Wind Vertical Speed: 0 mph Wind Cross Speed: 0 mph LOS Angle: 0 degrees Cant Angle: 0 degrees Target Speed: 0 mph Target Angle: 90 degrees Zero Range: 25 yards Zero Height: 0 inches Zero Offset: 0 inches Temperature: 59.6 °F Barometric Pressure: 29.92 in Hg Relative Humidity: 0.0 % Altitude: 0 feet Air Density: 100 % of Sea Level Calculated Table Elevation: 10.354 moa Azimuth: 0.000 moa Range Velocity Energy Momentum Drop Windage Lead Time (yards) (ft/sec) (ft-lbs) (lbs-sec) (inches) (inches) (inches) (sec) 0 3253.7 1292.8 0.79 -2.6 0.0 0.0 0.000 25 3151.8 1213.1 0.77 -0.0 0.0 0.0 0.023 50 3052.2 1137.7 0.75 2.4 0.0 0.0 0.048 75 2954.8 1066.2 0.72 4.5 0.0 0.0 0.073 100 2859.5 998.5 0.70 6.4 0.0 0.0 0.098 125 2766.2 934.5 0.68 8.1 0.0 0.0 0.125 150 2675.0 873.8 0.65 9.4 0.0 0.0 0.153 175 2585.6 816.4 0.63 10.4 0.0 0.0 0.181 200 2498.2 762.1 0.61 11.2 0.0 0.0 0.211 225 2412.6 710.8 0.59 11.5 0.0 0.0 0.241 250 2328.9 662.4 0.57 11.5 0.0 0.0 0.273 275 2247.1 616.6 0.55 11.1 0.0 0.0 0.306 300 2166.5 573.2 0.53 10.3 0.0 0.0 0.340 325 2087.4 532.1 0.51 9.0 0.0 0.0 0.375 350 2010.0 493.4 0.49 7.2 0.0 0.0 0.411 375 1934.3 456.9 0.47 4.9 0.0 0.0 0.450 400 1860.5 422.7 0.45 1.9 0.0 0.0 0.489 425 1788.7 390.7 0.44 -1.6 0.0 0.0 0.530 450 1718.9 360.8 0.42 -5.8 0.0 0.0 0.573 475 1651.2 332.9 0.40 -10.8 0.0 0.0 0.617 500 1585.5 307.0 0.39 -16.5 0.0 0.0 0.664 Input Data @ 50 yard zero Muzzle Velocity: 3240.0 ft/sec Chronograph Distance: 10.000 feet Ballistic Coefficient: 0.255 Drag Function: G1 Bullet Weight: 55 grains Sight Height: 2.60 inches Sight Offset: 0.00 inches Wind Range Speed: 0 mph Wind Vertical Speed: 0 mph Wind Cross Speed: 0 mph LOS Angle: 0 degrees Cant Angle: 0 degrees Target Speed: 0 mph Target Angle: 90 degrees Zero Range: 50 yards Zero Height: 0 inches Zero Offset: 0 inches Temperature: 59.6 °F Barometric Pressure: 29.92 in Hg Relative Humidity: 0.0 % Altitude: 0 feet Air Density: 100 % of Sea Level Calculated Table Elevation: 5.803 moa Azimuth: 0.000 moa Range Velocity Energy Momentum Drop Windage Lead Time (yards) (ft/sec) (ft-lbs) (lbs-sec) (inches) (inches) (inches) (sec) 0 3253.7 1292.8 0.79 -2.6 0.0 0.0 0.000 25 3151.8 1213.1 0.77 -1.2 0.0 0.0 0.023 50 3052.2 1137.7 0.75 -0.0 0.0 0.0 0.048 75 2954.8 1066.2 0.72 1.0 0.0 0.0 0.073 100 2859.5 998.5 0.70 1.7 0.0 0.0 0.098 125 2766.2 934.5 0.68 2.1 0.0 0.0 0.125 150 2675.0 873.8 0.65 2.3 0.0 0.0 0.153 175 2585.6 816.4 0.63 2.1 0.0 0.0 0.181 200 2498.2 762.1 0.61 1.6 0.0 0.0 0.211 225 2412.6 710.8 0.59 0.8 0.0 0.0 0.241 250 2329.0 662.4 0.57 -0.4 0.0 0.0 0.273 275 2247.1 616.6 0.55 -2.0 0.0 0.0 0.306 300 2166.5 573.2 0.53 -4.0 0.0 0.0 0.340 325 2087.4 532.1 0.51 -6.5 0.0 0.0 0.375 350 2010.0 493.4 0.49 -9.5 0.0 0.0 0.411 375 1934.3 456.9 0.47 -13.0 0.0 0.0 0.450 400 1860.5 422.7 0.45 -17.1 0.0 0.0 0.489 425 1788.7 390.7 0.44 -21.8 0.0 0.0 0.530 450 1718.9 360.8 0.42 -27.2 0.0 0.0 0.573 475 1651.2 332.9 0.40 -33.4 0.0 0.0 0.617 500 1585.5 307.0 0.39 -40.3 0.0 0.0 0.664
Link Posted: 7/18/2003 4:48:59 AM EDT
bvmjethead......you interested in tryin' to balance my checkbook??
Link Posted: 7/18/2003 11:34:24 PM EDT
NateZ, how are you mounting your EOTech, straight to the flattop? How far forward? TS
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