New Posts New Posts RSS Feed - Do I  Understand DOA
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Check GunBroker.com for SWFA's No Reserve and No Minimum bid firearm auctions.

Do I Understand DOA

 Post Reply Post Reply   Topic Search Topic Search  Topic Options Topic Options
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 17:08
wcooper View Drop Down
Optics GrassHopper
Optics GrassHopper


Joined: September/02/2010
Location: San Antonio. Tx
Status: Offline
Points: 2
I understand that DOA is a non programable system where you always sight-in at 100 yards and for some calibers the dots below fall into a known yardage as opposed to BDC which I understand. Please tell me if I am correct.
Also is Mil-Dot programable? Is It more like BDC or DOA.
Thank You
Willie
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 17:10
Rancid Coolaid View Drop Down
Optics Jedi Master
Optics Jedi Master
Avatar

Joined: January/19/2005
Location: United States
Status: Online
Points: 7699
Willie,


WHAT?


And welcome.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 17:59
stickbow46 View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: January/07/2009
Location: Benton, Pa
Status: Offline
Points: 4673
+1 with RC.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 19:50
Bitterroot Bulls View Drop Down
Optics Master Extraordinaire
Optics Master Extraordinaire
Avatar

Joined: May/07/2009
Location: Montana
Status: Offline
Points: 3380
The DOA reticle has subtensions between its marks.  Just sight in for your desired range and use a ballistic calculator to match the subtensions to your trajectory.  Bushnell should provide literature telling what the subtensions are.

I don't know what you mean by programmable.

Welcome.


Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 20:35
Urimaginaryfrnd View Drop Down
MODERATOR
MODERATOR
Avatar
Resident Redneck

Joined: June/20/2005
Location: Iowa
Status: Offline
Points: 13877
Imagine if you will a crosshair that is thin all the way from top to bottom intersected by an identical one side to side--- yep --- that is how they used to be. Leupold and others decided to improve the crosshairs to make them more useful by placing marks across the line below center known as BDC or DOA or what ever you want to call them they are lines that in theory should correspond to most common hunting rifle calibers for bullet drop give or take a little.  Since we know that rifles of a particular caliber will shoot lighter bullets faster and heavier bullets slower we also realize the BDC system is not perfect but still useful. No matter where you place the mark below center and no matter what bullet your shoot fast or slow that mark will eventually correspond to some distance the trick is to find out what distance that is for your particular bullet in your caliber.  Here is how to do it.  Zero the center of the crosshairs at 100 yds or at 200 yds or any distance you might select for your known zero. No matter what power the scope is on that point will hold true. At powers lower than the maximum power of the scope with a second focal plane scope (reticle appears to remain the same size no matter which power) your marks below center will only be able to be used  at one power typically the highest power.  The reason is that as you change power from high to low the field of view grows wider as you can see looking through the scope. However the reticle remains looking the same so as you decrease power there becomes more and more distance between what the marks will represent at any given distance say 100 yds.  Example at 9 power the distance between the center X and the dot below might represent 3 inches but if you dial down to say 6 power that distance between the center X and the dot below might represent 5 or 6 inches.  With a second focal plane scope the reticle appears to grow smaller in direct porportion to the power and with a mil dot scope like the 3-9x42 Super Sniper the mil dot can both be used to mil dot range find  or can be used for known holdover.  One can print a chart for trajectory at http://www.jbmballistics.com/cgi-bin/jbmtraj_drift-5.1.cgi
Using the chart for your bullet at your elevation and temperature etc you can approximate how much drop you will experience however this is an educated guess and each rifle is different so you test your theory on the rifle range.   The other way to find out what distance marks below the center X represent is to Zero at 100 yds then hold the center X on the 200 yd target and shoot a group of three or so on the 200 yd  target then go up and mark the center of the group with something large and bright enough to see from 200 yds through your scope then go back to 200 yds and put the X on the center of the target and look to see which mark in your reticle corresponds to the mark on the target.  Test similarly for other distances.   It does not matter by which name they call the marks on the reticle what matters is that you test it on the range and see what your rifle does and use that information to aid you in making an good shot. 

Edited by Urimaginaryfrnd - September/02/2010 at 20:36
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: September/02/2010 at 22:48
wcooper View Drop Down
Optics GrassHopper
Optics GrassHopper


Joined: September/02/2010
Location: San Antonio. Tx
Status: Offline
Points: 2
Thanks, and by programmable I meant obtaining the information showing yardage at the circles no matter your sight-in point.
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Similar Threads: "Do I Understand DOA"
Subject Author Forum Replies Last Post
BUSHNELL ELITE 6500 DOA 600 RETICLE FOR SALE KIMBER8400AT Optics For Sale 5
Bushnell Legend Ultra DOA 200 Viper4 Tactical Scopes 0
Trying understand bullet drop and MOA. tpcollins Rifle Scopes 4
understanding reticle subtension 338LM Rifle Scopes 7
Bushnell Elite 6500 2.5-16x42 DOA 600 penguin6 Optics For Sale 1
Important Info on Bushnell's Elite w/DOA reticle shooter07 Rifle Scopes 6
Bshnll Trophy D.O.A v Legend Mildot H&R222 Rifle Scopes 8
Bushnell DOA???? gnab2 Rifle Scopes 2
Bushnell Elite 6500 2.5-16x42 DOA 600 fireroad Rifle Scopes 2
Bushnell Elite 2.5-16x 42 DOA JF4545 Rifle Scopes 1


This page was generated in 0.266 seconds.