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zeiss Rapid Z calculator |
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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Posted: July/09/2008 at 22:24 |
Recently a poster suggested the rapid z group of reticles could be set for a given distance, 200, 300 etc in the same manner as the Leupold BAS system is set up in the varmit reticle. Briefly the Leo system is based on holding the bars at 300, 400 and 500 yds, then adjusting the magnification power to accomodate for the drop, thus cartridge groups that drop less have a higher power, usually the highest and the power (taking advantage of a property of sfp) lowered for those groups having more drop thus "lifting" them. This of course reduces the magnification of the image.
Zeiss's system (using Exbal) calculates the drop based on the "cut" off points of the bars on which ever reticle is being used.
So after referencing some simulated print outs from JBM on line calculator,
a load of 155 gr Amax, at 2900 fps in 308 with bc of .435 gave a hint that this would be a good start. so the z calculator was set up with the following on 14 power.
bar 3 300
bar 4 403
bar 5 502
bar 6 600
bar 7 697
bar 8 791
for the 800 z reticle and was about as close as I could get at hitting the bars and the yardages.
it was difficult to get the load to 2900 fps. but found a good group around 2800 fps.
so, in theory all I would need to do would be to back to the calculator plug in the 2800 fps then hit the optimize power button. for a reduced magnification that would still give me the same drop figures. --- and it gave 9.29.
So spending the day testing this load at ranges from 200 to 800 yds on 8 x 11 steel targets for 100 rds. at this power setting. my percentage hit was around 85%. (was just throwing the cases of the misses in a pile and count later).
given a serious attempt I feel this could be in the 90's -- damn nice set up.
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Steelbenz
Optics Jedi Knight ROLL TIDE ROLL Joined: January/03/2006 Location: Heart of Dixie Status: Offline Points: 5153 |
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Dale, quick Question?
what was the powder (IMR ?, Varget or ?) and amount to get 2900fps with an 155GR Amax. and what was the lenth of the test barrel?
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"Don't argue with a fool! From a distance you can't really tell who's who!"
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Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
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47 grs. of varget, but I couldn't get to 2900 fps with the 24" barrel without significant pressure signs as suggested by the hogdgon internet. 45.5 worked great for 2800 fps.
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