Rimfire BDC Reticle Breakdown

Everyone wants the easy button and the industry has listened. Scope manufacturers have designed series of scopes known as BDC or Bullet Drop Compensation Reticles to accommodate the easy button request of shooters.  

The idea is that the reticle inside the scope already has Bullet Drop built in it, so just pick up the rifle and shoot your target at given distance. Rimfire BDC scopes are some of the most common scopes in the world. Everyone has an old 22LR sitting in the closet or in the gun safe and it would be so handy if a scope did all the work for you. Allowing for you to pick up some cheap ammo from the store and hit the range or timber.

Pictured is a Rimfire BDC Reticle here is how you are educated on how to use it. 

• 50 yard target - hold center X and zero your scope.
• 75 yard target - Hold 1st dot down (also known as substitution C1) on target.
• 100 yard target - Hold 2nd dot on target (C2)
• 125 yard target - Hold 3rd dot on target (C3)
• 150 yard target - Hold the location where the Reticle goes from thin to thick (C4)

Wow that is handy and so easy!  But is it a lie.... 

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Are Rimfire BDC Reticles a Lie?

The short answer is No - They are not a lie, but they are very misleading. 
Manufacturers have to make products that fit the masses. They can't make one-off scopes for each person with their pick of ammo and gun combo that is out there in the world. So they have compiled data on what is the most common ballistic performance of 22's on the market and developed their reticles to get you in the ball park. 

Wait... So how does it work for me?

There is a high likelihood that your BDC Reticle is lying to you. Here why - 

1. Second Focal Plane Scope- BDC scopes usually come exclusively in "SFP" scope designs. This means that the Reticle stays the same size inside your scope no matter what magnification you are at. That translates to your Subtensions  will have different values. In your user manual of the scope you will see where they will tell you the operating magnification of the scope. Example - If you have a 4-12x power scope the manufacturer may say the working reticle magnification is 12x. Meaning the BDC Drop Values only pertain when the scope is on that set power. 
2. Velocity & Bullet Weight - If you don't use the same ammunition,  barrel length  and environment they tested with the subtensions will not hold true.  In the image above it states that for this reticle to work you need a Muzzle Velocity of 1,250 FPS. Bullet weight - this is an assumption  of the shooter. Most 22LR Ammo is 40gr. We can only assume this is a requirement of this  scope. If you don't meet these exact specs this reticle is a lie and it will not work as advertised. 

Real World Rimfire BDC Usage

Do I need to throw away my Rimfire BDC? 
 NO! It still can be used and used effectively. 

Here is how the above BDC Rimfire Reticle performed on one of our CZ457 Varmint Rifles, 20.5 inch barrel.  Using SK Standard Plus 40gr 22LR Ammo at the factory prescribed scope magnification.  

• 50 Yard Zero 
• Subtension 1 (C1) - 68 Yard Target Vs 75 yards from Chart
• Subtension 2 (C2) - 89 Yard Target  Vs 100 yards from Chart 
• Subtension 3 (C3) - 110 Yard Target  Vs 125 yards from Chart
• Subtension 4 (C4) - 132 Yard Target  Vs 150 yards from Chart

As you can see if we would have just take the values given to us from the manual we would would never be able to properly engage the target with our Gun and Ammo combo if we wouldn't have tested out real life performance. 

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Conclusion

• BDC Reticles can work just fine.
• Don't listen to what the manual says.
• Is it the best for Marksman/Precision shooting? - No, but it might be all you need!
• Take the time to chronograph your ammo and time behind the trigger to see what those subtensions really do for your set up.
• ​Most importantly have fun shooting!