Why a Simple Duplex Reticle is More Versatile Than BDC Reticles

[wildcat junkie]

You've all heard me express my opinion on this subject before. Here is a YouTube video that proves my point.

 

 

[phade]

I don't know anyone who uses BDC who doesn't plug in details to get them on point or close enough to verify at range the specific distances that apply.

Almost all of the major BDC makers have an app to recalibrate to "close enough" to then verify. Sig even matches it up with their BDX when you use the RF and scope.

It's really NO different than xbow scopes that go on a variety of models. The whole premise is if you use something as advertised - and the manufacturers clearly state detail in the manuals.

If someone is competition shooting or benchrest, etc. I get it. But for hunters, use the app, verify at range and then it's good to go with your data set. Most of our scope caps have waterproof tape with yardage lines on them and corresponding details. 

[dbHunterNY]

I agree with what the guy is saying but how is this at all prove your point that a simple duplex is more versatile than a bdc?? A bdc is a effectly a duplex with additional reference points. Even if the one hash mark is 305 yards I can't hold over as precisely with a duplex vs calling 305 close enough and using it as if it were 300. It's an entirely different argument and topic of someone not using it correctly or verifying POI with their specific setup.

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[wildcat junkie]

1 hour ago, dbHunterNY said:

I agree with what the guy is saying but how is this at all prove your point that a simple duplex is more versatile than a bdc?? A bdc is a effectly a duplex with additional reference points. Even if the one hash mark is 305 yards I can't hold over as precisely with a duplex vs calling 305 close enough and using it as if it were 300. It's an entirely different argument and topic of someone not using it correctly or verifying POI with their specific setup.

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You can plug in the same data needed for the BDC to be correct (MV measured over a chronograph, bullet BC and THE DISTANCE OF THE SIGHTLINE ABOVE THE BORE AXIS) for the known subtention of your duplex. That will give you 3 reference points.

For example if I use the bottom of the top post as my 100yd POI I will be zeroed at 250yds and the top of the bottom post POI can also be calculated,. I don't have my data in front of me at the moment, but with my 8mm06 A.I. it will be around 350yds.

Furthermore, the + or - 3" PBR for the crosshairs will be 280yds, so no holdover needed with a center of vitals hold from just in front of the muzzle to 280yds

A duplex reticle can also be used for range estimation. The gap between the top and bottom post subtends 15" in a Leupold 3-9 standard duplex at 300yds so I know that if a mature buck does not fill the gap it is over 300yds. Then the top of the bottom post would be the appropriate aim point.

The same subtention values can be used for windage compensation. 

All this with a reticle that is quicker to acquire in the event of a quick shot.

Edited March 25, 2021 by wildcat junkie

[grampy]

1 hour ago, wildcat junkie said:

You can plug in the same data needed for the BDC to be correct (MV measured over a chronograph, bullet BC and THE DISTANCE OF THE SIGHTLINE ABOVE THE BORE AXIS) for the known subtention of your duplex. That will give you 3 reference points.

For example if I use the bottom of the top post as my 100yd POI I will be zeroed at 250yds and the top of the bottom post POI can also be calculated,. I don't have my data in front of me at the moment, but with my 8mm06 A.I. it will be around 350yds.

Furthermore, the + or - 3" PBR for the crosshairs will be 280yds, so no holdover needed with a center of vitals hold from just in front of the muzzle to 280yds

A duplex reticle can also be used for range estimation. The gap between the top and bottom post subtends 15" in a Leupold 3-9 standard duplex at 300yds so I know that if a mature buck does not fill the gap it is over 300yds. Then the top of the bottom post would be the appropriate aim point.

The same subtention values can be used for windage compensation. 

All this with a reticle that is quicker to acquire in the event of a quick shot.

Great information WJ. Especially for the longer range shooters.

The majority of my shots at deer is under 100 yards. And many are 50 and under. Using this set up for zero would have me aiming too low, to hit vitals. As well as I have been conditioned over a lifetime, to look for the center of the reticle, when picking up quickly on a close deer that just pops in. I want the center of the reticle to be on that deer, and that my POI corelates to where I aim! Any other way would certainly mess up my simple mind, with complex computations in the heat of the moment. But that's just me! Others may not be nearly as simple minded.

[mowin]

42 minutes ago, grampy said:

Great information WJ. Especially for the longer range shooters.

The majority of my shots at deer is under 100 yards. And many are 50 and under. Using this set up for zero would have me aiming too low, to hit vitals. As well as I have been conditioned over a lifetime, to look for the center of the reticle, when picking up quickly on a close deer that just pops in. I want the center of the reticle to be on that deer, and that my POI corelates to where I aim! Any other way would certainly mess up my simple mind, with complex computations in the heat of the moment. But that's just me! Others may not be nearly as simple minded.

I'm the same. Most shots 100yds or less.  I want the center of the reticel to be where the bullet goes.  Every once in a while I get 250-300yrd shot. Time on the range behind the trigger makes those shots possible.  

[Robhuntandfish]

1 hour ago, grampy said:

Great information WJ. Especially for the longer range shooters.

The majority of my shots at deer is under 100 yards. And many are 50 and under. Using this set up for zero would have me aiming too low, to hit vitals. As well as I have been conditioned over a lifetime, to look for the center of the reticle, when picking up quickly on a close deer that just pops in. I want the center of the reticle to be on that deer, and that my POI corelates to where I aim! Any other way would certainly mess up my simple mind, with complex computations in the heat of the moment. But that's just me! Others may not be nearly as simple minded.

bingo - exact same for me.  Thats why my favorite scope is this below.  I put it on all my guns.  100 yards I set it at 1" high at crosshairs when sighting in.  Then in the heat of the moment i just put this circle - which is the the size of the bullseye on a target at 100 yards. Also for long range i only use my 30-06 which at 200 yards is only 2" low at that setting and still in the vitals.  Covers all i need in NY.  Now if really long range bench shooting i would prob prefer a scope to adjust for shooting those ranges over a BDC, but long range hunting 400 yards + prob a BDC as it would be less to fumble with.  

Edited March 25, 2021 by Robhuntandfish

[wildcat junkie]

1 hour ago, grampy said:

Great information WJ. Especially for the longer range shooters.

The majority of my shots at deer is under 100 yards. And many are 50 and under. Using this set up for zero would have me aiming too low, to hit vitals. As well as I have been conditioned over a lifetime, to look for the center of the reticle, when picking up quickly on a close deer that just pops in. I want the center of the reticle to be on that deer, and that my POI corelates to where I aim! Any other way would certainly mess up my simple mind, with complex computations in the heat of the moment. But that's just me! Others may not be nearly as simple minded.

But that's' the whole point of + or - 3" PBR sighting in. You don't have to "compute" anything, just aim for center of vitals and squeeze the trigger. I was just pointing out that a simple diplex reticle, at any range out to 350yds will do anything that a BDC reticle will with a much more practical reticle for quick target acquisition.

59 minutes ago, mowin said:

I'm the same. Most shots 100yds or less.  I want the center of the reticel to be where the bullet goes.  Every once in a while I get 250-300yrd shot. Time on the range behind the trigger makes those shots possible.  

Ah, but there's the rub. The bullet will only go "where the center of the reticle is" at one point along the arc of the trajectory when sighted in at close range. Typically most scopes are mounted about 1 1/2" to 1 3/4" above the bore access. It's even worse with "see through mounts" that can move the LOS more than 2" above the bore axis. The POI starts out below the POA at close ranges. Sight in at 50yds and it will immediately start to fall below the LOS as the yardage increases.

Let's assume a 9" vital zone for a whitetail deer. With + or - 3" PBR, the bullet will impact "where the reticle is" at about 30yds, be about 1" high at 50yds and 2 1/2" high at 100yds. One would not "miss" the vitals if the crosshairs were placed just behind the pocket of the shoulder at any of those ranges. At 150yds the bullet would impact 3" high, still a quick humane kill with a center of vitals hold. After 150yds the bullet impact would start to get closer to the POA until it was dead on at 250yds. Somewhere around 275- 300yds (depending on velocity and ballistic coefficient) the bullet will impact 3" below the crosshair POA. Still a quick humane kill; with center of vitals hold.

 

I have killed something like 30 deer in the 21 years I have lived in NYS at ranges from 50 to about 275yds. I never hold over or under at any of those ranges, I aim for the (vertical) center of the vitals. I have never missed a deer that could attributed to how I sight my rifles in, nor have I ever had to trail a deer more than 50yds. If they don't drop right there, I usually find them within 20yds.

Edited March 25, 2021 by wildcat junkie

[mowin]

1 minute ago, wildcat junkie said:

But that's' the whole point of + or - 3" PBR sighting in. You don't have to "compute" anything, just aim for center of vitals and squeeze the trigger. I was just pointing out that a simple diplex reticle, at any range out to 350yds will do anything that a BDC reticle will with a much more practical reticle for quick target acquisition.

Ah, but there's the rub. The bullet will only go "where the center of the reticle is" at one point along the arc of the trajectory when sighted in at close range. Typically most scopes are mounted about 1 1/2" to 1 3/4" above the bore access. It's even worse with "see through mounts" that can move the LOS more than 2" above the bore axis. The POI starts out below the POA at close ranges. Sight in at 50yds and it will immediately start to fall below the LOS as the yardage increases.

Let's assume a 9" vital zone for a whitetail deer. With + or - 3" PBR, the bullet will impact "where the reticle is" at about 30yds, be about 1" high at 50yds and 2 1/2" high at 100yds. One would not "miss" the vitals if the crosshairs were placed just behind the pocket of the shoulder at any of those ranges. At 150yds the bullet would impact 3" high, still a quick humane kill with a center of vitals hold. After 150yds the bullet impact would start to get closer to the POA until it was dead on at 250yds. Somewhere around 275- 300yds (depending on velocity and ballistic coefficient) the bullet will impact 3" below the crosshair POA. Still a quick humane kill; with center of vitals hold.

 

I have killed something like 30 deer in the 21 years I have lived in NYS at ranges from 50 to about 275yds. I never hold over or under at any of those ranges, I aim for the (vertical) center of the vitals. I have never missed a deer that could attributed to how I sight my rifles in, nor have I ever had to trail a deer more than 50yds.

If I did the long range shooting you do, I would probably change the way I sight in or practice.  Guess I'm just so used to shooting, sighting in my way, that changing anything now would just confuse me. 

Never liked the BDC reticle. Scope looks to cluttered. 

[wildcat junkie]

26 minutes ago, mowin said:

Never liked the BDC reticle. Scope looks to cluttered. 

We certainly can agree on that. Too much chance for confusion in the heat of the moment.

[dbHunterNY]

Maybe I'm hung up on one statement. Not saying I disagree with the content posted. I just still don't think a duplex is as versatile. Practicality wise it's all a moot point and sight picture or reticle your scope has is subjectively better or not compared to the next. Honestly my perfect scope would be a first focal plane with MOA hash marks for both elevation and windage. Not familiar with mils.

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[Steve D]

Personally never had the need for anything other than a Duplex reticle. Like Grampy and others most of my shots are 100 yards or less. I have no desire to shoot one long distance. The longest I ever made was 225 yards and the duplex did fine. I cranked up the variable a bit and hit where I wanted.

 An accurate rifle, the ability to shoot, and not having to think about what dot to use is more important as far as I am concerned.

[dbHunterNY]

Personally never had the need for anything other than a Duplex reticle. Like Grampy and others most of my shots are 100 yards or less. I have no desire to shoot one long distance. The longest I ever made was 225 yards and the duplex did fine. I cranked up the variable a bit and hit where I wanted.
 An accurate rifle, the ability to shoot, and not having to think about what dot to use is more important as far as I am concerned.

Many common deer rounds with a duplex you're good to 300 yards by putting crosshair right on its back anyway. Beyond that most people aren't shooting or don't get a deer that far away.

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[wildcat junkie]

On 4/2/2021 at 11:21 PM, dbHunterNY said:

Many common deer rounds with a duplex you're good to 300 yards by putting crosshair right on its back anyway. Beyond that most people aren't shooting or don't get a deer that far away.

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My 8mm-06 Ackley Improved shooting a 200gr Speer Hotcor at 2900fps has these POIs at various point of the standard duplex reticle.

Edited May 2, 2021 by wildcat junkie

[dbHunterNY]

My 8mm-06 Ackley Improved shooting a 200gr Speer Hotcor at 2900fps has these POIs at various point of the standard duplex reticle.

Plugged it into ballistic app I use and result seemed close to what I'd expect. Your drop something around 13-14" at 350 yards? Seems like bottom post would be more than that but maybe your more than a 9x scope. Anyway I get your point that you can use the reference points in a standard duplex similar to a bdc.

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[dbHunterNY]

Not your traditional setup and honestly my go to deer rifles have basic duplexs on them. Last rifle I setup has MOA windage and elevation hash marks with red dot. Can turn red dot off for more precision or if your battery dies you're still good. Varies in intensity from last light bright to sunny daylight bright. I'm really liking it.


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