The change in NRA High Power rules a few years ago allowing optics on Service Rifles quickly prompted scope manufacturers back to their drawing boards. Leupold is the latest to offer an optic, the new Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1, specifically designed to conform to the new rules while still adding a rules-legal bell and whistle or two. Does it make the grade for High Power? Let’s take a look.
Regarding optics, NRA High Power Rifle Rule 3.1 states: “The rifle may have an optical sight (reflective sights are considered optical sights) with a maximum of 4.5X are permitted. Only commercially manufactured scopes that were produced with a maximum magnification of 4.5X and that have a maximum objective lens of 34 mm may be used. If an optical sight is used, the same optical sight must be used in all stages of a course of fire (changing sights is not permitted). The centerline of an optical sight shall be no higher than 3.5 inches above the centerline of the bore.”
Iron sights are still permitted, but shooters that are highly competitive use a scope, especially ones in pursuit of Excellence In Competition (EIC) points toward a Distinguished Rifleman Badge. Limiting the optic centerline to no more than 3½ inches above the bore centerline means a flat-top upper is required, as mounting a scope on the carry handle would place it too high. The situation has pretty much rendered my iron-sighted, A2-style AR-15 Service Rifle moot; I perhaps should have sold it (at least the upper) when the new optics rule hit the streets, but you know how hard it is to part with an accurate rifle (yes, I went to a scope, too). Rule 3.1 is short and sweet; the only features of the scope it really addresses are magnification and objective size.
Fit For High Power
With a maximum magnification of 4.5X and a 24 mm objective lens, Leupold’s Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1 complies with Rule 3.1. The 24 mm objective lens is mounted inside a 30 mm maintube, which gives the scope a straight profile in front of the turrets. While the rule permits a larger objective lens, Leupold’s 24 mm lens eschews an objective “bell” housing, which permits lower mounting of the scope.
Weight is a feathery 18 ounces. Leupold says eye relief varies from 3.7 inches to 3.9 inches, depending upon magnification, but two-tenths of an inch isn’t something most shooters will notice. Elevation and windage turret knobs are large and bear numbers in oversize print; both adjust in 1/4-MOA-click increments. Both have Leupold’s “Zerolock” feature that locks the knobs when returned to zero; pushing the wide button on the turret edge unlocks the knobs. According to the spec sheet, full range of elevation and windage adjustment is 165 MOA, meaning 82½ minutes from center in each direction, vertical and horizontal.
As received, zero on the elevation knob is not in the center of adjustment, but at the bottommost point. There are three rows of numbers on the elevation turret knob. The bottom row is marked in 1/4-MOA increments, the second row in one-minute increments and the third in two-minute increments. After one complete revolution of the knob, the shooter refers to the next higher row to see the actual setting, rather than needing to recall how many revs that’s already been put on. The full range of elevation adjustment as marked, then, is 72 minutes, despite the 82½ minutes stated on the spec sheet.
Windage adjustment, too, is given as 165 MOA, or 82½ minutes left and right. The turret cap is marked only to 12 minutes left or right, and a limiter stops any further rotation. The limiter, attached to the Zerolock button, is a tiny pin on the turret cap underside that rides in a groove on the turret, which stops turret rotation at only a half-turn. Once the scope is mounted and elevation and windage zero determined with a collimator or by shooting, the turret caps can be removed by first loosening two 1/16-inch Allen set screws on the edge; then the turret caps can be reinstalled with the zero marks (“0”) facing the shooter. The Zerolock feature locks the turret at this point, preventing rotation unless the button is pressed.
High Power Reticle, Low Power Variable
On NRA High Power targets, the “aiming black,” the center black scoring rings, is larger on the 300- and 600-yard targets, enough that they appear to be the same size as the 200-yard target at 200 yards. That is, no matter which of the three distances you shoot from, the target always looks the same size when sighting on it. Like other scopes dedicated to High Power competition, the Leupold’s reticle center is a circle of apparent size (about eight MOA) to just encircle the aiming black, with a peek of white around the edge. Therefore, Leupold’s Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1 optic is necessarily a second-focal-plane (SFP) reticle type, so that the reticle stays the same size as magnification changes.
In the center of the reticle’s circle is a microscopic black 1/2-MOA dot. If it were illuminated (and perhaps it is on other Mark 4HD models, see below) it could be useful, but as it is, the black dot is pretty much lost in the target’s aiming black. Leupold made an interesting and useful improvement on the standard vertical and horizontal stadia; rather than being solid lines, each is composed of two fine parallel lines that converge to a point just before touching the circle in the center. The slim parallel lines are an excellent aid in precisely focusing the ocular lens to individual eyesight. The ocular lens focusing ring is necessarily a bit stiff, so that no locking ring is necessary.
There is no parallax adjustment on the Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1; it is manufactured to be parallax-free at 150 yards, Leupold’s standard for rifle scopes. While necessary on high-magnification scopes, on a variable scope with such a low magnification as 4.5X, lack of parallax adjustment is not a serious shortcoming. Still, High Power Rifle shooters will benefit from attaching a lens reducer to the Mark 4HD scope. White Oak Armament, which caters specifically to High Power Rifle competitors, announced it will soon offer a lens reducer to fit the Mark 4HD.
The magnification ring lever’s purpose on a variable scope is to implement rapid changes in magnification, which isn’t an issue in High Power competition, and the lever is an unnecessary projection, so in practice I would set magnification at 4.5X and remove the throw lever, accomplished by simply unscrewing it.
Range Test
I fixed the Mark 4HD to my National Match rifle’s Picatinny rail with Leupold’s Mark AR one-piece IMS (Integrated Mounting System) mount and adjusted for a preliminary zero with a collimator. Elevation was pretty much spot-on but due to variables between scope, mount and rifle rail, I had to remove the scope’s windage cap to disable the limiter so that I could crank on enough windage—15½ minutes—to get a zero. This is done by loosening the knob’s two Allen-head set screws to remove the cap, and rotating the slot-headed adjustment under the cap. The preliminary adjustment still leaves plenty of windage adjustment at 600 yards even for a windy day.
I further evaluated the Mark 4HD by firing at 100 yards at an NRA SR-21 reduction of the 300-yard NRA High Power target (to evaluate the circular reticle) from a heavy rest on a concrete bench. Finding the zero with IMI Systems Razor Core 77-grain HPBT-Match ammunition required adding another 2¼ minutes right windage and 4½ minutes elevation beyond the collimator’s “on-paper” adjustment. I include that comment to point out the usefulness of a collimator, which isn’t perfection, but simply to save ammo when sighting in a scope.
I “shot the square” to check elevation and windage adjustment accuracy. You know the drill: shoot a group, add five minutes right windage, shoot, add five minutes elevation, shoot, put on five minutes left windage, shoot and drop elevation five minutes. Shooting the square a second time verified repeatability of adjustments, as well. The Mark 4HD’s accuracy of adjustment appears to be spot-on, with a fractions of an inch plus-or-minus difference that I attribute to my own eyesight, the low magnification and a bit of wind. Light transmission through the scope is excellent, the image is sharp and clear, and the eight-MOA circular reticle presents a sight picture ideal for use on NRA High Power Rifle targets.
With an MSRP of $1,149.99, Leupold’s Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1 offers high quality and excellent features in a mid- to higher-price scope dedicated to High Power competition. Leupold also offers the Mark 4HD in four other magnification ranges, 2.5-10X 42 mm, 4.5-18X 52 mm, 6-24X 52 mm and 8-32X 56 mm, and with a variety of different reticles, some illuminated, some with side focus (parallax adjustment), in both MOA and MILRAD versions. Learn more at leupold.com.
