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  1. #1
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    Range Report: Hornady 5.56mm 75 Grain TAP SBR

    Hornady 5.56mm 75 Grain TAP SBR







    Hornady’s latest edition to their line-up of 5.56mm ammunition is their 75 grain TAP SBR load (#81295.) The “SBR” abbreviation stands for short-barreled rifle; the intended platform for the usage of this ammunition.










    This ammunition is loaded with a 75 grain flat-base, soft point bullet. This bullet is not a bonded projectile; it does however utilize an array of cannelures intended to lock the lead core of the bullet to the gilding metal jacket. The cartridge is sealed and crimped at the case-mouth.

















    Here’s some pics comparing the 75 grain TAP SBR projectile to some other modern heavy .22 caliber projectiles.


















    This ammunition is loaded in brass cases with a head-stamp that reads: “Hornady 5.56 NATO”. The primer-pockets are crimped and sealed.







    Contrary to erroneous information that has been posted on the Internet claiming that this ammunition “contains a propellant closer to gel than powder”, the form of the powder that this ammunition is actually charged with resembles that of a number of modern “ball” powders.








    Accuracy


    I conducted an accuracy (technically, precision) evaluation of the Hornady 5.56mm 75 grain TAP SBR ammunition following my usual protocol. This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group-reduction techniques (e.g. fliers, target movement, butterfly shots).

    The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation.

    All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VAR-X III set at a magnification of 25X and adjusted to be parallax-free at 100 yards. A mirage shield was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.









    The Wind Probe.







    The test vehicle for this evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar Walther barrel. The barrel has a 223 Wylde chamber with a 1:8” twist.









    Prior to firing the Hornady 5.56mm 75 grain TAP SBR ammunition, I fired a 10-shot control group using a hand-load topped with the Sierra 55 grain BlitzKing. That group had an extreme spread of 0.88”.












    Three 10-shot groups of the Hornady 5.56mm 75 grain TAP SBR ammunition were fired in a row with the resulting extreme spreads:

    1.28”
    1.41”
    0.93”

    for a 10-shot group average extreme spread of 1.21”. The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group. The mean radius for the 30-shot composite group was 0.44”.


    All fired cases ejected briskly from the rifle in a 4:30 direction. The spent cases were gathered approximately 12 feet from the rifle.



    The smallest 10-shot group . . .







    The 30-shot composite group . . .









    Lastly, for the Internet Commandos in our viewing audience, I fired a 3-shot group of the 75 grain TAP SBR ammunition from 100 yards. That group had an extreme spread of 0.36”.










    ....





    Velocity




    Since the Hornady 5.56mm 75 grain TAP SBR ammunition is intended for use in short-barreled rifles, I chronographed the ammunition from the shortest barrel that I had on hand; a Noveske 14.5” N4 barrel. This barrel is chrome-lined and has a 5.56mm NATO chamber with a 1:7” twist.









    Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings. If there is a difference, the chronograph “flags” the shot to let you know that the data is invalid. There was no invalid data flagged during this testing.

    The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph.












    Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker.









    Atmospheric conditions

    Temperature: 77 degrees F
    Humidity: 33%
    Barometric pressure: 30.05 inches of Hg
    Elevation: 950 feet above sea level


    The muzzle velocity for the 10-shot string of the Hornady 5.56mm 75 grain TAP SBR ammunition fired from the Noveske 14.5” N4 barrel was 2460 FPS with a standard deviation of 12 FPS and a coefficient of variation of 0.49%.


    For comparison, I also chronographed Hornady’s 5.56mm 75 grain TAP T2 ammunition back-to-back from the same barrel. The muzzle velocity for this load was 2649 FPS with a standard deviation of 11 FPS and a coefficient of variation of 0.42%.

    For additional comparison, I chronographed the Speer LE 223 Remington 75 grain Gold Dot ammunition from the same 14.5” Noveske N4 barrel. The muzzle velocity for the 75 grain Gold Dot ammunition was 2463 FPS with a standard deviation of 12 FPS and a coefficient of variation of 0.49%.








    ....

  2. #2
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    Nuts...I was hoping for a short barrel test I've been looking for this stuff but no one locally has it (and don't get me started on shipping to AK!). If I can ever find any, I'll test with my 10½" SBR.
    Curious about the powder... does it seem to be a mix? They claim better short barrel use, and some are saying online they heard it was due to a mix of powders, like a slight amount of fast burning pistol powder added in. Doesn't look like it in your picture tho. I'd sure like to get my hands on some to test!
    -----------------------------------------------
    Jim
    "You can never have too many guns" - my wife's actual comment
    Alaska Fun

  3. #3
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    I would like to have all that equipment that Molon has

    I will hunt around and see if I can find a gel test on this round... I too would like to see velocity test and all that out of a 10.5".

  4. #4
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    Aaaaaaaand found a box. Dropped the wife at her weekly Doc visit, and to kill time I hit a few places. Now have a box to test on Friday! Also grabbed the non-SBR TAP to see how it's different.

    And yeah... my testing will NOT be anywhere near the level of Molon's. Sorry.
    -----------------------------------------------
    Jim
    "You can never have too many guns" - my wife's actual comment
    Alaska Fun

  5. #5
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    These guys LE Sales at miwall seem to have one 200 round case in stock at a pretty good price. Problem is, they only sell to LEO's (or they would already be OOS ).
    NRA Benefactor Member
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  6. #6
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    Per a conversation with a Hornady rep at the OTOA conference this round's optimized for 10.5-12.5" SBR's. The developer of this round was there at another booth but I did not get to speak with him unfortunately.
    NRA Life Member - NRA RSO

  7. #7
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    I have a 10.5" just waiting for it. I'm on the "notify me" list at a couple of sites.
    NRA Benefactor Member
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    "I won't be wronged, I won't be insulted, and I won't be laid a hand on."
    John Wayne - "The Shootist"

  8. #8
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    Quote Originally Posted by Jerry R View Post
    I have a 10.5" just waiting for it. I'm on the "notify me" list at a couple of sites.
    I got lucky...this thread reminded me to look again (I've looking for a month or two), and the ONE store locally I have seen the TAP stuff at had the SBR in stock that morning. LEO/Mil sales only, but they also include other first responders so this knuckle dragging fireman was allowed to get a box. I still plan to hit the range tomorrow with my 10½" if I don't get swamped in honey-do's. I also grabbed a box of the standard 75gr TAP to see how much difference there is with the SBR version. I don't have all the fancy equipment that Molon has, so it will simply be chrono'd with my magnetospeed.
    -----------------------------------------------
    Jim
    "You can never have too many guns" - my wife's actual comment
    Alaska Fun

  9. #9
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    Quote Originally Posted by SwissyJim View Post
    I got lucky...this thread reminded me to look again (I've looking for a month or two), and the ONE store locally I have seen the TAP stuff at had the SBR in stock that morning. LEO/Mil sales only, but they also include other first responders so this knuckle dragging fireman was allowed to get a box. I still plan to hit the range tomorrow with my 10½" if I don't get swamped in honey-do's. I also grabbed a box of the standard 75gr TAP to see how much difference there is with the SBR version. I don't have all the fancy equipment that Molon has, so it will simply be chrono'd with my magnetospeed.
    Chrono data out of a 10.5 will be most excellent information to have! Just getting the rough idea is awesome.

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