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Posted: 3/3/2011 7:47:36 AM EDT
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I'm going to sight in my latest build- lightweight 16" CAR (BCM LW upper) with a 1/7 twist - for a ranch/truck gun. Most of our shots are 80-100 yards; but we regularly have predators pop out 50-60 yards away and occaisionlly get to shoot as far as 150 yards. I'm primarily using 62gr Speer soft nose ammo that we get from Goverment. So,
1. I'm wondering about sighting it in dead-on at 80? What do y'all think? If I do that- ROUGHLY, what would it be shooting at 50yds, 100yds, 125yds and 150yds? Just looking for guestomates here, fellas- I'm trying to figure out best sight in distance that will keep me from having to compensate for distance and still keep me in the kill zone on a coyote whether I'm shooting 50, 80, 100 or 125yds. 2. If I sight in as described above, or something relatively close, and I let my kid shoot a jackrabbit with it at 10yds, it's essentially going to shoot low by the amount of distance between the centerline of the bore and the centerline of the sight, correct? 3. If you dont think I should sight it in at 80yds, what distance do you think I should use, and why? Thanks to all who reply! |
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The best advice I ever got was "Sight it in at the distance you intend to shoot at the most".
Most of your shots are 80-100 yards. So when you sight in you should be able to nail a varmint sized target at 90 yards. Then move your target in to 80 yards and see how high it is (not very), then back out to 100 and see how low (again, not very). Now move it in to 50-60, at that point it might be high enough you'll want to adjust elevation or hold low. Make a note of how many clicks or how much hold. Repeat for 150, don't forget to reset elevation to your 90 yard zero. Finally bring in a jackrabbit sized target to 10 yards and shoot it. I can't find the link but there was an old school hunter that showed how to use a piece of cardboard cut to the height of the game you intend to shoot. You line that up on some reference mark on your scope and know where to hold by reference instead of by clicks or dots or guessing. |
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I personally think the Revised Improved Battlesight Zero will work great for you (50yard/200meter zero). The bullet is within +or- 2 inches all the way out to 250 yards.
http://www.ar15.com/forums/topic.html?b=3&f=18&t=328143 
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Setting a high velocity .224 caliber bullet for any particular short range with sights so high above the bore line is a waste. Calibration is nearly impossible. If you take a look at these two sites and read the short version below, you may decifer a simple way to set the sights for all short ranges and still not lose the long range capability. Long range being perhaps 300 yards with a CAR sight system.
The two locations below have a wealth of info regarding setting A2 carryhandle sights in 20" and 16" ARs: http://thefiringline.com/forums/showthread.php?t=286804 http://www.ar15.com/forums/topic.html?b=3&f=18&t=512335 What those site end up meaning is this. Extracting the basic parts of those threads is sometimes difficult. As an example of what the CAR system can do with an A2 carry handle sight, I took out a new ArmaLite lower, J&T Expedition 16" CAR upper today with the addition of a XS Sight Systems no offset flip sight. The Expedition 16" CAR is a heavy under the handguard, light in front of the FSB barrel with a muzzle break porting system drilled into the barrel with no extra flash hider. 16" total length to the end of the recessed crown. Before I went, I took the set screw out of the rear sight rotors. This released the lower elevation wheel rotor that has threads to adjust the elevation stem from the upper numbered wheel rotor which only has the setting numbers and does not change the elevation stem. I set the lower wheel so that it started bottomed out at a click, moved to a free click, moved to a second click representing 100 yards, moved to a third click representing 200 yards, moved to a free click, and moved to the fifth and final spot representing 8/3. I put the set screw back into the assembly and tightened it so that 8/3 was at the fifth and final spot. Conceptually, the side of the drum now is now bottom at 8/3-5, 8/3-4, 8/3-3 (100), 8/3-2 (200), 8/3-1, 8/3 (300). That is all there is to the idea of RIBZ Revised Improved Battlesight Zero. (read above for endless details. Leaving one more at the bottom has uses.) I took it out to shoot at 200 yards set on 8/3-2 clicks with Federal 55FMJ. That is the to be zeroed 200 yard setting. 1 round in the dirt to see where it went. Right windage added and front sight raised one click to zero elevation. Note that the rear sight is not moved to set the zeroing elevation. Then I left the elevation alone and zeroed the windage counting right clicks starting with the sight all the way to the left. Having used the front sight to calibrate the rear elevation rotor settings, the elevation dial is set for 50-100-200-300. The windage number is written down (you can just as well use left or right of the center mark for windage). This is a basic zero for Federal 55 grain FMJ, Fiocchi 55 FMJ, PMC 55 FMJ, AMEagle 55 FMJ. Zeroing with other loads would work just as well. Tried a 55 grain Sierra BlitzKing handload and cut the group sizes in half, but about 2 inches lower than the factory Federal 55FMJ. A single click up would zero that load at 8/3-1. Tried a 69 Sierra bulleted Federal GMM .223 load and it shot higher than the Federal 55FMJ. Going 8/3-5 (the bottom click) zeroed it at 200 yards. Blew the hell out of an 8" rock at 200 yards with that load. Notes made on settings. With 55 grain bullets, the upper rotor's 4 would be very close to the 400 range. No fuss and easy enough to do. It requires a total tool expenditure of one allen wrench for the set screw. The XS sight with no offset is not required. I just like them. When switching from the small apperature for zeroing to the large apperature for wide angle viewing, the small apperature flips to the front. At the same time, add two clicks of right windage and the large apperature is rezeroed. For easy references, I put some white nylon filled fingernail polish into the slots on the rotor wheel knerling IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII at the correct sports for 8/3-2 (200 yards) and 8/3-3 (100 yards). The 200 yard setting 8/3-2 is also the 50 yard setting. On the windage knob, the same fingernail paint identifies the windage zero for the small apperature. If you flip the small apperature forward, turn the knob two clicks right so the painted spot stays alongside the small apperature. |
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