Project DT 006: Live Sight Steyr 50 BMG
Smith Tactical/ GunEngine.com was presented with a factory new Steyr 50 BMG Heavy Sniper Rifle and asked by the customer to install High 50 BMG rings, a Leupold Mark 4 Sniper Scope, and then bore sight, live sight, and test the weapon system for accuracy and function.
On the initial test, we calibrated the Mark 4 (2nd focal plane/ mil dot reticle system) at 40 and 300 yard zeroes, then final MPB zero of 400 yards (actual 500), actual MPB at 450 yards, and max range (mil dot/2 meter target) at 1050 yards, on a gun "rated" at 2000 yards. Beyond a mile (1,700 yards), the drop and accuracy of a rifle with a 33 inch barrel are too variable to consider the system consistently reliable, even with the Mark 4 at 25x and premium Hornady ammo.
Upon bore sighting to the black, it was found that the MPB elevation was perfect with the High 50 rings/Mark 4 combination at 400 yards right out of the box, and only required a two click down/right adjustment to be dead center. This combination of rings and scope is amazing. After the initial test, the rings were re-checked for torque (initial: 65 inch pounds cross bars/15-- light firm finger/thumb-- for top screws), and did not fall within Smith Tactical tolerances (.03). These were returned, and replaced with new Badger High 50's. The new rings did not vary at all.
All testing was done with the Hornady 2.54" A-Max 50 BMG at 750 grains with a BC of 1.050, MV of 2,800 fps and ME of 13,000 f/p. The scope was re-set for a BC of .67 before shipment, due to the customer's ammo specs. Bullet drop at MPBR (450) with the A Max was an actual -51.69 (-11 clicks from 500 zero). Recoil was approximately 83 foot pounds. Alititude for all tests was 4470. Temperature was 70 F, BP was 29.81. Humidity was 10%, and there were no to very light cross winds.
Scope Tips
This system is now set for maximum efficiency and ease of use for a 2 yard high target at 450 yards. From that baseline, leisure (competition) sighting should be done with a sighting/ranging scope or ranging binoculars, and elevation simply dialed into the incredible Mark 4 based on range.
Medium time frame faster sighting can be done with shooter reticle estimation of range, then dialing in correct yardage in clicks. To go from 450 yards with the customer's preferred load (just like dropping back from zero to the MPBR) will require negative clicks, approximately -15 at 300 yards, and -25 at 200 yards. Shooter reticle ranging with the (2nd plane) Mark 4 should be done at 25x. The 4 gives 1 mil for each dot in the reticle. Target range is target size in yards times 1,000, divided by mils. If a 6 foot tall target has his feet on the crosshairs and his head is on the second mil dot (at 25x), he is at 1,000 yards. With MPB ballistics set at 12 inches, +060 clicks give a consistent two foot group at 1,000 yards with the customer's ammo drop of -271.
"Hold over" ranging is not recommended with a system designed to be shot accurately at over 500 yards with a bipod or sand bags, and weighing over 30 pounds, but the Mark 4 is legendary for hold over accuracy. Since each mil as scope is currently set is about 3.5" at 100 yards, or 3.39 MOA, you can get a quick holdover estimate with this scope by multiplying the range/100 (4 for 400 yards) by the MIL INCH (NOT MOA), or 4 x 3.5 = 14 inches (for example), which is the "dot to dot" value for each mil through the scope. The "technique" is to take the bullet drop of the round you're using, and hold over the number of mils that dividing the bullet drop by the 14 inch mil value would give you. A drop of 42 inches at a bit over 400 yards with the Hornady A-Max would give you a calculated HO of 4 dots with this method, as an example. Of course this is not necessary with this system at this range, as the scope was already zeroed at 500 and set to an actual MPB with predetermined clicks (-11) at a 12 inch allowable target size. For reference when MOA adjusting, the Mark 4 has 1/4 click MOA adjustments. Practically, estimating "air" at ranges over 300 yards is iffy at best, unless you have a natural "talent". As a fighter pilot, our customer for this system could probably do it!
Scope was removed for shipping, rings left on. Eye relief was set at 5 inches for safety (maximum) due to recoil (exercise CAUTION if sighting uphill!). Leupold touts it's "long" eye relief (between 3 and 5) but seasoned pistol hunters know that's about the minimum. Rings have been set so customer can re-set scope to the max forward position that is comfortable for his cheek/vision and shoulder placement (our SWAT customers even request mounting the rear ring on the exposed eyepiece threads occasionally, which is within spec for this scope), then add/remove the scope quickly for field sorties. The precision-machined top mount screws on the high 50 are specified at 15 in/lbs, which is practically light to firm finger/thumb tight using the Leupold wrench. Most shooters don't carry i/p gauges in the field. Recoil dictates conservatism, but the high 50's are forgiving and very precisely machined. Height was determined as the minimum necessary to clear bolt, fit the 1913 pic rail, not interfere with ejection, and yet remain as low as possible to the barrel within these constraints.
Performance
This rifle proved to be incredibly accurate, even at 1,000 yards. Move over Quigley. 6" and tighter groups were consistently achieved at 400 yards, and 18" groups were achieved from time to time with some tinkering at 1,000. Most good rifle marksmen cannot hit a standing Elk consistently with an 18" target zone over 300 yards. Even with a huge 50mm scope, it is hard to quickly acquire a jeep at 1,000 yards, let alone a little piece of paper. Given that this round is intended for stopped materiel, not moving targets, the larger "engine target" size makes near-mile shots possible, if not practical. Don't forget that the "mile" shots you hear about are with guns having 4 foot or longer barrels. This can make a difference of 10 inches in accuracy over a 28 inch barrel (the Steyr is 33), but you're then lugging around a 60 pound rifle. This amazing Steyr is quite light by comparison at 28.5 pounds.
Penetration with armor piercing rounds is calculated at 1.5 inches of steel (with 700 military ammo), although we did not use armor piercing rounds for this test. MOA fine tuning for windage and elevation, from those seen in the targets below, were then made using traditional center-group measurement click adjustments to "move the group".
Although this is advertised as a "sub MOA" gun at 1,000 yards, we found this unrealistic if you require consistency. That would mean your groups are CONSISTENTLY tighter than the center of the 10 ring of a 1,000 yard competition target (under 10 inch groups at 1,000-- 10 ring is 20 inches). Sure, the world record is 3 or 4 inches, but with several "bench" series, the best we could do is 18 inches with consistency, which was measuring bullet shape and wind more than our skill! We're curious how some of these studies measure "sub MOA" in a round that pokes a half inch hole with every shot anyway! Certainly MOA measurements below 300 yards become part hype. If you're allowed to shoot 10 3-shot groups, and one is at 6 inches at 1,000 yards, and that is your definition of sub-MOA, then yes, this gun MORE than qualifies.
The "down a jet in flight" mystique of the 50 BMG is also hype, as the A-max has a maximum altitude of about 16,500 feet straight up, with no penetrating power at that altitude. And the odds of actually hitting something moving that fast are about like trying to take out a satellite in geostationary orbit with your .22. These myths are perpetrated by gun banners, so reporters beware! CNN was actually gullible enough to fire a Barrett through a jet door at about 30 yards, and "extrapolate" from there. Don't tell them that Weatherby makes at least 6 rifles more practical in weight, recoil and caliber than Barrett if you really want to harrass a Hamas jet on takeoff.
Little known fact: The 50 BMG is actually a scaled up 30-06. John Browning liked the ballistics and profile of the venerable 30-06 so much that he designed his "jeep killer" with the same ratios! The 50 BMG is still the oldest and most widespread military caliber in the world. Wildcatters are encouraged to continue development of the range of ballistic and design options, as this is the surest way to defeat the banners. Thanks DT, forever and always, and God bless you and yours.
A curious and interesting side note on shipping this monster: the very substantial Austrian crate is out of spec for USPS, not insurable at Fedex, and contents require "inspection" at UPS. How do you remove the steel bands, "show" the contents to UPS for insurance, then re-band with your local UPS center staff (and a few other curious customers) standing around agape? Answer is DT's secret!
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