The Leupold Special Purpose Reticle (SPR) was designed to allow users to successfully engage targets with greater flexibility than generally possible with other reticle styles. This reticle also preserves the instinctive fire capabilities of the Leupold Circle Dot reticle in short range, low magnification engagements typical of Close Quarter Battle in the 21st century. This unique blend of capabilities allows the various optics platforms equipped with this reticle to perform equally well in open desert, heavy cover, or the urban environment.
A key component in the operation of the Leupold Special Purpose Reticle is the ability to estimate range using the milliradians (mils) scale. A milliradian
is a unit of measure that corresponds to different distances at different ranges.
For example:
The subtension of 1 mil equals 3.6 inches at 100 yards or 36 inches at 1,000 yards. In metric units, the correspondence is 1 mil equals 10 centimeters at 100 meters or 1 meter at 1,000 meters. Knowing this subtension and knowing the size of the target (or a reference object near the target) allows the distance to the target to be estimated with considerable accuracy.
The SPR Reticle is comprised of a three heavy posts connected by fine stadia lines, much like the German #4 reticle. On the fine stadia, large tic marks are located at 5 mil intervals, with small tics bisecting the large tics which indicate 2.5 mil intervals. A large center circle of 10 mil diameter surrounds a fine, .3 mil dot which is located at the intersection of the fine crosshair and provides a quick point of acquisition. Fine stadia are .1 mil thick, while thicker posts are .5 mil thick. The 2.5 mil tic marks are .3 mil wide, while the wider 5 mil hash marks are .5 mil wide. All subtensions indicated are with the riflescope set on the highest power. The result is a reticle that allows
numerous different measuring possibilities and almost limitless ranging ability for the trained operator.
The hash marks and tic marks on the vertical crosswire are calibrated to two popular long range service rounds, the 5.56mm NATO SS109 at 2800 fps
(carbine velocity) and the 7.62mm NATO 118 LR at 2600 fps (rifle velocity). After properly zeroing the rifle or carbine, the tic marks will correspond with bullet drop at the ranges listed below. (See Table 1) Actual distance values can vary by +/- 20 meters at the indicated distance depending on actual target size.
As can be seen from the accompanying diagram (Table 2) the mil tic marks and hash marks can be used as range estimating devices, provided a target of 1 or 2 meter height is available. This range estimating ability will allow the user to quickly and accurately estimate distance and engage targets at longer ranges. At close range, the large circle allows rapid target acquisition when ranging is not necessary and the target is still within the Point Blank Range (PBR) of the weapon.
To use the system, accurately estimate the range to the target using the mil system, then, use the corresponding aiming point that is matched to your cartridge to engage the target. For targets that are inside 200 yards, a center mass shot can be achieved by using the center aiming dot and a 100 yard zero.
Moderator
Originally Posted by Tzoid
Posting Permissions
Reply With Quote
Bookmarks