Scope BDC question.

Comrade Ogilvy

Comrade Ogilvy

CGN Regular
Rating - 100%
24   0   0
Location
Ontario
Hi,

I'm new to shooting and have been browsing for my first scope. While looking at the Vortex Strike Eagle 1-6, and the Bushnell AR Optic 1-4, I noticed something that I'm having trouble understanding.
The Vortex reticle center aiming point is good for 20-200 yards, with the next BDC line for 300 yards etc. The Bushnell center is for 100 yards, with the next BDC line for 200 yards. Both scopes are geared for 5.56/223.

So my question is, if you had two identical rifles side by side, firing the same ammo at the same targets, wouldn't the bullet trajectory be the same? Why would you have to adjust your aim from 100 to 200 yards with one scope, but not the other?
Sorry in advance if I'm ignorant of the obvious.
 
I believe the design of the strike eagle, when zeroed at 200 yards has a small post above Center that will be your 100 yard zero and then the hash marks lower will be your zeros for further ranges. It's really just a slight difference in reticle design and a bunch of marketing babble.
 
From the Vortex Strike Eagle 1-6x24 manual;

"Riflescope Adjustments
Using the Reticle for Bullet Drop Compensation
Standard BDC Technique
Most rifles will work well zeroed in at 50 yards using the center
crosshair. Consult the riflescope owner’s manual for sight-in
techniques. For most popular 5.56mm / .223 loads, the center
crosshair will then provide good accuracy from 20 to 200 yards.
For most popular 7.62mm / .308 loads, the center crosshair will
provide good accuracy from 20 to 150 yards.
At further distances, the lower hashmarks can be used as aiming
points at the corresponding aiming points listed on page 3."

"Standard Bullet Drop for Popular 5.56 mm / .223 Loads
Main crosshair zeroed 50 yards, use from
20 to 200 yards:
Hashmark Distance
1st 300 Yards
2nd 400 Yards
3rd 500 Yards
4th 600 Yards"

Not sure that answers your question and I haven't done your experiment, YMMV.
 
Yeah thanks, I read that in the manual too which lead me to my question. I don't know why one scope would have the same aim point up to 200 yards, and another scope have an adjustment from 100 to 200 yards.

@Markus - The manual doesn't say anything about the small post above the center crosshair.

http://www.vortexoptics.com/uploads/M-00128-0

I guess to be more clear what I'm asking, if we both had the same rifle sighted in with different scopes, and we both hit center target at 100 yards, which one would be more accurate at the 200 yard target? One of us will be aiming with the same crosshair, while the other will be adjusting their aim with the BDC.
 
Last edited:
Comrade Ogilvy said:
I don't know why one scope would have the same aim point up to 200 yards, and another scope have an adjustment from 100 to 200 yards.
Click to expand...

The simple answer to this question is because company A can't build the same thing as company B.

They all have to come up with a design that's different than the other guys yet serves the same purpose.

You're guess is as good as mine as to which one is actually better.
 
Comrade Ogilvy said:
https://www.perfectunion.com/vb/att...223-556-shoot-flat-mini-14-pmc-ballistics.jpg

I found this interesting little chart. I would say it's because the Vortex is zeroed in at 50 yards, and the bushnell at 100 yards. The chart shows different bullet drops at the same distance. I'm not smart enough to figure out why that is. :)
Thanks guys.
Click to expand...

Thanks for the chart.

50 yards zero, It is due to bullet rise through its trajectory before gravity overcomes velocity. At 100 yards it rises 0.8683" and then gravity takes hold between the 150 and 175 yard distance. At 200 yards it drops -1.3898" yielding a "zone" of accuracy of +0.8683" to -1.3898" from 50 to 200 yards.

100 yard zero; The zone is -0.4453" at 50 yards and rises to the 100 yard distance and starts dropping -3.136" at 200 yards

FWIW, I own the 1-6x24 Strike Eagle and zero at 50 yards.
 
Wester said:
Thanks for the chart.

50 yards zero, It is due to bullet rise through its trajectory before gravity overcomes velocity. At 100 yards it rises 0.8683" and then gravity takes hold between the 150 and 175 yard distance. At 200 yards it drops -1.3898" yielding a "zone" of accuracy of +0.8683" to -1.3898" from 50 to 200 yards.

100 yard zero; The zone is -0.4453" at 50 yards and rises to the 100 yard distance and starts dropping -3.136" at 200 yards

FWIW, I own the 1-6x24 Strike Eagle and zero at 50 yards.
Click to expand...

Thanks for taking the time to explain that. If you don't mind me asking, do you like the Strike Eagle and would you recommend it for a beginner? That is one of the scopes I have my eye on.
 
Comrade Ogilvy said:
Thanks for taking the time to explain that. If you don't mind me asking, do you like the Strike Eagle and would you recommend it for a beginner? That is one of the scopes I have my eye on.
Click to expand...

I like it so far. There are few other options I did consider at the time but the Strike Eagle was on sale and I could not argue with their warranty.
 
You must log in or register to reply here.
Back
Top Bottom