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Bullet Drop Compensation with Duplex Reticles-326 viewsIf this buck was 420 yards away, could you take this shot with confidence? This article describes how a hunter can use a duplex reticle and a variable power scope to compensate for bullet trajectory at longer ranges, or commonly referred to as bullet drop compensation (BDC).
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Reference data used during this project for Bullet Drop Compensation (BDC) & windage-354 viewsUsing the duplex reticle measurements and ballistic tables created specific for each rifle, I generated reference cards detailing range, hold-over, scope magnification for BDC, and windage. You can download a MS Excel spreadsheet from HuntingNut.com that allows you to create a reference card for your rifle including ranging estimates based on using your duplex reticle and power setting to fill the post-to-crosshairs with the game’s chest.
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Range Estimation-336 viewsMost target estimation for deer size targets assumes a chest depth of 18 inches (bottom of the chest to the top of the back).
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420 Yard Results-287 viewsRifles used in this BDC project were a .243 w/ Simmons 4-12x, .308 w/ Leupold 3-9x, and .270 w/ Bushnell 2.5-16x Mil-Dot, left to right. Target was at 420 yards. The .308 grouping was shot first with insufficient wind compensation. Wind becomes a predominate factor at longer ranges.
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200 Yards or Meters-371 viewsRange Estimating (left) using Duplex Reticle with a magnification set for 18” from crosshairs to lower post at 400 yards or meters. Shot placement (right) showing hold-over to achieve correct Bullet Drop Compensation (BDC) for corresponding range.
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250 Yards or Meters-317 viewsRange Estimating (left) using Duplex Reticle with a magnification set for 18” from crosshairs to lower post at 400 yards or meters. Shot placement (right) showing hold-over to achieve correct Bullet Drop Compensation (BDC) for corresponding range.
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300 Yards or Meters-407 viewsRange Estimating (left) using Duplex Reticle with a magnification set for 18” from crosshairs to lower post at 400 yards or meters. Shot placement (right) showing hold-over to achieve correct Bullet Drop Compensation (BDC) for corresponding range.
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350 Yards or Meters-320 viewsRange Estimating (left) using Duplex Reticle with a magnification set for 18” from crosshairs to lower post at 400 yards or meters. Shot placement (right) showing hold-over to achieve correct Bullet Drop Compensation (BDC) for corresponding range.
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400 Yards or Meters-558 viewsRange Estimating (left) using Duplex Reticle with a magnification set for 18” from crosshairs to lower post at 400 yards or meters. Shot placement (right) showing hold-over to achieve correct Bullet Drop Compensation (BDC) for corresponding range.
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Leupold Boone & Crocket Reticle-416 viewsLeupold has a capable set-up with range estimation and wind compensation available on their VX-III scopes. Range estimation is accomplished by adjusting magnification until the animal’s chest fills the crosshairs up to the tip of the top thick post then reading the range in hundreds of yards on the other side of the power ring. Range estimation assumes an 18-inch chest depth. Wind compensation on their Boone & CrockettTM Reticle is for a 10 mph crosswind component. Depending on the performance of your rifle, zero ranges are designed to be 200 or 300 yards with some calibers requiring a lower power setting for accurate trajectory matching which is marked by a small triangle at 8x on their 3.5-10x and 11.2x on their 4.5-14x scopes. You can fine tune the BDC reticle to your rifles performance by adjusting the magnification to provide proportionally more or less bullet drop. In the case of my .308 and their 3.5-10x scope with a 200 yard zero, the BDC reticle would be tuned with the scope set on 8.8 magnification. Specific reticle details regarding calipers, bullet velocities, and MOA of reticle markings can be downloaded from the Leupold’s website, file name “Ballistics Reticle Supplement”. The Leupold VX-III scopes have less range of magnification than other manufactures, e.g., 3.5-10x vs 3-12x, 4.5-14x vs 4-16x. Leupold’s 4.5-14x is nice at the higher power settings but if you read the specification, their 4.5 is really a 5x magnification (4.9x).
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Burris Ballistic Plex and Ballistic Mil-Dot Reticles-383 viewsBurris has a Ballistic PlexTM and a Ballistic Mil-DotTM Reticle. They both have similar BDC tics on the lower portion of the reticle but the latter gives you the advantages of Mil-Dots on the upper and horizontal cross-hairs. The Ballistic Mil-DotTM is only offered on higher power scopes, 4-16X and above and 14x is used for the BDC reference. There is no wind compensation integrated with the Burris reticles. The Ballistic PlexTM crosshairs are designed for a 100-yard zero for standard calibers and 200 yards for flatter shooting calibers. The Ballistic Mil-DotTM crosshairs are designed for a 100-yard zero and intended for flat shooting calibers. Burris has a wealth of information on their website but it is hard to find. Try this web address, www.burrisoptics.com/reticles.html, to download Burris’ BDC files. With a Ballistic PlexTM and 100-yard zero, my .308 would be 2 to 3 inches high beyond 300 yards. Using a 200-yard zero, the ballistic match had even more disparity between this BDC reticle and my .308 rifle’s trajectory.
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Cabela's Rangefinder Reticle-754 viewsCabella’s Rangefinder BDC scopes have the quickest range estimation to shot down-range that you can find. You don’t have to twist any knobs, take your eyes off your target, or take your rifle off your shoulder to read a dial. The reticle grows and shrinks with magnification, like a European-style scope, so range estimation and BDC work at any magnification setting. This means there is no capability to change magnification to tune the BDC reticle for your rifles performance. The advantage of this set-up is simplicity, e.g., you don’t have to remember to set a magnification to get the correct BDC or worry that it might get bumped off your setting. There are no thick posts to help with low-light situations. The scope is intended for a 200 yard zero with 8 inches of trajectory drop at 300 yards, 23 inches at 400, and 44 inches at 500, typical of .30-06-like performance with boat-tail bullets. The only tuning you can do to match your rifle’s performance is to sight your rifle in slightly high or low at 200 yards to better fit the trajectory drop marks at longer ranges. You can also do simple windage estimation because the centerline circles allow you to project a 9-inch cone either side of the center crosshair at any range. If this BDC reticle closely matches your rifle’s performance, like it did my .308 and the .30-06 factory ammo I checked, it is a good option to consider.
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