Angle Cosine Indicator (ACI)
The "Angle Cosine Indicator," ® is a simple tool for hunters in mountainous terrain, and utilized to obtain their corrected for gravity distance to target.
The ACI® is a vault solid, water resistant precision instrument; quiet and made from aircraft grade aluminium, which is anodized in a flat black colour.
The Co-Sine numbers are Laser Engraved onto the body in five (5) degree increments.
The lens is shatter proof, shock proof and resistant to chemicals such as acetone and cleaning solvents.
Completely mechanical, there are no batteries or electronics to fail.
The "A.C.I."™ works on any shoulder mounted weapon system . When the weapon is held at an angle, the "A.C.I."™ indicates the co-sine number of that angle by means of a highly visible index mark. The co-sine number is then multiplied to the "EstablishedRange", (sloped distance to target), or inputted into the data entry point of the users Ballistic Targeting Software, which gives you the corrected for gravity distance to target.
There are two ways to mount the device. One way is to utilize a short, Weaver Base scope ring (not sold here), which is mounted onto the scope tube, at 90 degrees.
Another way is to utilize a Badger Ordinance mount designed to attach to a standard picantinny rail. The mount works on all day and most night scopes. Details of the Badger Ordinance mount are below.
How does an Angle Cosign Indicator work? One of three ways, but simple.
a. Method #1 and the most accurate is to input the cosine number into your ballistic software; i.e. Nightforce Ballistic Targeting Software or other ballistic software, that runs on either your home PC, Pocket PC or Palm Pilot. This is because the software takes into account the trigonomics of the fact that the bullet will still travel the full distance to target, and maintain a similar time of flight.
b. Method #2, is to multiply the cosine number to your MILRAD or MOA hold for your distance to target as indicated on your data card. For example, if your moa hold for 600 yards is 11 moa, and .87 is indicated by the ACI, you would then multiply .87 X 11moa, and obtain a corrected for gravity distance of 9.57 moa. This is fairly accurate, (Caliber Specific) although not as accurate as utilizing ballistic software. This is called the "Improved Rifleman Method."
c. Method #3, is to multiply the cosine number to your sloped distance. This will deliver the flat line distance to target, or what we call the bottom leg of the triangle. For example if you are shooting at a known 350 metres, and the ACI reading is .85, then the rifle should be sighted for a 280 metre shot.
If you experiment with your ballistic software, you will find that there can be as much as eight (8) MOA difference between method #1 and method #3. Method #1 is the most accurate & preferred method.
Now, adjust the sight elevation knob (come-ups) on your scope, for the "corrected range".
Price: $199.00 plus postage and packing ($7.99 for Australian Customers). Buy Now
Badger Ordinance Mount
Angle Co-Sine Indicator mount, by Badger Ordnance. Machined aluminum mount allows you to mount our Angle Cosine Indicator directly to your Picatinny rail. It will fit any M1913 MIL STD mount, attaches with 2 soft point set screws so it will not mar your mount.
Weighs less than 1/2 oz. and is Anodized Black.
Image: ACI with Mount
Price: $88.00 plus postage and packing ($7.99 for Australian Customers). Buy Now
NOTE: If you're buying both ACI and Mount, only pay $7.99 postage for both items.