Molon
02-03-16, 16:45
Hornady 5.56mm 62 Grain TAP Barrier Ammunition
https://app.box.com/shared/static/6k5ljfl4fskpcg2jh69mvolahhdexz5s.jpg
https://app.box.com/shared/static/vcnqbuwpry6bh3ules67q8s83qyqcnca.jpg
Hornady’s 5.56mm 62 grain TAP Barrier ammunition (#8125N) is loaded with a 62 grain flat-base, soft-point bullet with a cannelure. This bullet has the largest amount of exposed lead at the meplat of any of the soft-point barrier-blind loads that I’ve evaluated.
https://app.box.com/shared/static/0tah1mfsotpq0k1uz7hm009xrff0uxrf.jpg
https://app.box.com/shared/static/rkgnr3srux58rxz7dbnv6cyqi0g0d5ru.jpg
Contrary to erroneous information that has been posted on the Internet, the bullet used in this ammunition is not a bonded projectile.
https://app.box.com/shared/static/teu6jwh48ss18jp3reiiuiu842o55cys.jpg
The case mouth is crimped and has an anaerobic sealant.
https://app.box.com/shared/static/nnwmfw5gmifx15gvfnjmreq5bm6xqkat.jpg
The primer pockets of this ammunition are crimped and have lacquer sealant. The case-heads read, “Hornady 5.56 NATO”. Hornady advertises that the ball powder used in this ammunition is temperature stabilized and has a flash retardant. The box label carries a warning that this ammunition is "NOT FOR USE IN .223 CHAMBERS".
https://app.box.com/shared/static/rws5fimbx7vl8ddj5ifwdxefp0sdlhie.jpg
Hornady advertises that this ammunition has a muzzle velocity of 3078 FPS when fired from a 20” 5.56x45mm NATO test barrel. For comparison, the US mil-spec for the velocity of M855 ammunition is as follows:
MIL-C-63989C [Amendment 4] states that the average velocity of the cartridges “shall be 3,020 feet per second (fps) plus or minus 40 fps at 78 feet from the muzzle of the weapon. The standard deviation of the velocity shall not exceed 40 fps.” This specification is for a 20” barrel and depending upon variables equates to a muzzle velocity of approximately 3105 FPS (plus or minus 40 FPS.)
As an aside, after reading the above specification, some of you may be wondering, “Why 78 feet from the muzzle?” The answer to that question is that this specification is simply an historical hold-over from the days when “circuit” chronographs (e.g. Le Boulenge Chronograph and the Aberdeen Chronograph) were used at Aberdeen Proving Ground, Frankford Arsenal and Springfield Armory. These types of chronographs required a significant distance between their first and second screens to produce accurate results.
As an example, when using the Boulenge Chronograph, the first screen of the chronograph was placed 3 feet in front of the muzzle and the second screen was placed 150 feet beyond the first screen. For those of you who might not be aware of the following fact; chronographs determine the velocity of the bullet at a point that is midway between the first and the second screen (i.e. not at the location of the first screen). Therefore, with the above spacing, the velocity of the bullet is determined for a point that is 75 feet from the first screen. So, add the three feet (from the muzzle to the first screen) to the 75 feet (the midway point of the screens) to obtain the “78 feet from the muzzle” distance.
https://app.box.com/shared/static/sj2isxyjw0iqtl0e1mcybqcg1g6hvaa8.jpg
https://app.box.com/shared/static/pj1xtbym3vnov134v10uaa87x5q0ro00.jpg
I chronographed the Hornady 5.56mm 62 grain TAP Barrier ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered 20” Colt M16A2 barrel.
http://www.box.net/shared/static/h8daj1jhf1.jpg
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.
https://app.box.com/shared/static/qecrizgcgxyzqztvq5xvb9gczasq71q3.jpg
https://app.box.com/shared/static/psjsdukng1c4p5efyw096kuka7p2aliu.jpg
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.
https://app.box.com/shared/static/rwruh372al3yh9kafscx370ewe74e6el.jpg
Atmospheric conditions
Temperature: 78 degrees F
Humidity: 54%
Barometric pressure: 29.99 inches of Hg
Elevation: 950 feet above sea level
The muzzle velocity for the 10-shot string of the Hornady 5.56mm 62 grain TAP Barrier ammunition fired from the 20” Colt barrel was 3069 FPS with a standard deviation of 18 FPS and a coefficient of variation of 0.58%.
....
I conducted an accuracy (technically, precision) evaluation of the Hornady 5.56mm 62 grain TAP Barrier 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 VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade 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.
https://app.box.com/shared/static/8ybmvvks8dyx1t1soslfzpxgah071370.jpg
The Wind Probe.
http://www.box.net/shared/static/lkg47ptc04.jpg
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.
https://app.box.com/shared/static/xac10i5ekkey7ih9ej5a3n6nmv5gy4j9.jpg
Prior to firing the Hornady 5.56mm 62 grain TAP Barrier ammunition, I fired a 10-shot control group using a hand-load topped with the Hornady 73 grain A-MAX bullet. That group had an extreme spread of 0.82”.
https://app.box.com/shared/static/gbg7e7zlyhec917m1gbomgv2fidrd3o9.jpg
Three 10-shot groups of the Hornady 5.56mm 62 grain TAP Barrier ammunition were fired in a row with the resulting extreme spreads:
1.79”
1.23”
2.44”
for a 10-shot group average extreme spread of 1.82”. 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 0.55”.
The smallest 10-shot group.
https://app.box.com/shared/static/bry07gfc7f80ncsj9ceefmh7simhsiq0.jpg
The 30-shot composite group.
https://app.box.com/shared/static/i3anenfdlyjny90me9zgz8u3oeoi7vs0.jpg
…..
https://app.box.com/shared/static/6k5ljfl4fskpcg2jh69mvolahhdexz5s.jpg
https://app.box.com/shared/static/vcnqbuwpry6bh3ules67q8s83qyqcnca.jpg
Hornady’s 5.56mm 62 grain TAP Barrier ammunition (#8125N) is loaded with a 62 grain flat-base, soft-point bullet with a cannelure. This bullet has the largest amount of exposed lead at the meplat of any of the soft-point barrier-blind loads that I’ve evaluated.
https://app.box.com/shared/static/0tah1mfsotpq0k1uz7hm009xrff0uxrf.jpg
https://app.box.com/shared/static/rkgnr3srux58rxz7dbnv6cyqi0g0d5ru.jpg
Contrary to erroneous information that has been posted on the Internet, the bullet used in this ammunition is not a bonded projectile.
https://app.box.com/shared/static/teu6jwh48ss18jp3reiiuiu842o55cys.jpg
The case mouth is crimped and has an anaerobic sealant.
https://app.box.com/shared/static/nnwmfw5gmifx15gvfnjmreq5bm6xqkat.jpg
The primer pockets of this ammunition are crimped and have lacquer sealant. The case-heads read, “Hornady 5.56 NATO”. Hornady advertises that the ball powder used in this ammunition is temperature stabilized and has a flash retardant. The box label carries a warning that this ammunition is "NOT FOR USE IN .223 CHAMBERS".
https://app.box.com/shared/static/rws5fimbx7vl8ddj5ifwdxefp0sdlhie.jpg
Hornady advertises that this ammunition has a muzzle velocity of 3078 FPS when fired from a 20” 5.56x45mm NATO test barrel. For comparison, the US mil-spec for the velocity of M855 ammunition is as follows:
MIL-C-63989C [Amendment 4] states that the average velocity of the cartridges “shall be 3,020 feet per second (fps) plus or minus 40 fps at 78 feet from the muzzle of the weapon. The standard deviation of the velocity shall not exceed 40 fps.” This specification is for a 20” barrel and depending upon variables equates to a muzzle velocity of approximately 3105 FPS (plus or minus 40 FPS.)
As an aside, after reading the above specification, some of you may be wondering, “Why 78 feet from the muzzle?” The answer to that question is that this specification is simply an historical hold-over from the days when “circuit” chronographs (e.g. Le Boulenge Chronograph and the Aberdeen Chronograph) were used at Aberdeen Proving Ground, Frankford Arsenal and Springfield Armory. These types of chronographs required a significant distance between their first and second screens to produce accurate results.
As an example, when using the Boulenge Chronograph, the first screen of the chronograph was placed 3 feet in front of the muzzle and the second screen was placed 150 feet beyond the first screen. For those of you who might not be aware of the following fact; chronographs determine the velocity of the bullet at a point that is midway between the first and the second screen (i.e. not at the location of the first screen). Therefore, with the above spacing, the velocity of the bullet is determined for a point that is 75 feet from the first screen. So, add the three feet (from the muzzle to the first screen) to the 75 feet (the midway point of the screens) to obtain the “78 feet from the muzzle” distance.
https://app.box.com/shared/static/sj2isxyjw0iqtl0e1mcybqcg1g6hvaa8.jpg
https://app.box.com/shared/static/pj1xtbym3vnov134v10uaa87x5q0ro00.jpg
I chronographed the Hornady 5.56mm 62 grain TAP Barrier ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered 20” Colt M16A2 barrel.
http://www.box.net/shared/static/h8daj1jhf1.jpg
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.
https://app.box.com/shared/static/qecrizgcgxyzqztvq5xvb9gczasq71q3.jpg
https://app.box.com/shared/static/psjsdukng1c4p5efyw096kuka7p2aliu.jpg
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.
https://app.box.com/shared/static/rwruh372al3yh9kafscx370ewe74e6el.jpg
Atmospheric conditions
Temperature: 78 degrees F
Humidity: 54%
Barometric pressure: 29.99 inches of Hg
Elevation: 950 feet above sea level
The muzzle velocity for the 10-shot string of the Hornady 5.56mm 62 grain TAP Barrier ammunition fired from the 20” Colt barrel was 3069 FPS with a standard deviation of 18 FPS and a coefficient of variation of 0.58%.
....
I conducted an accuracy (technically, precision) evaluation of the Hornady 5.56mm 62 grain TAP Barrier 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 VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade 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.
https://app.box.com/shared/static/8ybmvvks8dyx1t1soslfzpxgah071370.jpg
The Wind Probe.
http://www.box.net/shared/static/lkg47ptc04.jpg
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.
https://app.box.com/shared/static/xac10i5ekkey7ih9ej5a3n6nmv5gy4j9.jpg
Prior to firing the Hornady 5.56mm 62 grain TAP Barrier ammunition, I fired a 10-shot control group using a hand-load topped with the Hornady 73 grain A-MAX bullet. That group had an extreme spread of 0.82”.
https://app.box.com/shared/static/gbg7e7zlyhec917m1gbomgv2fidrd3o9.jpg
Three 10-shot groups of the Hornady 5.56mm 62 grain TAP Barrier ammunition were fired in a row with the resulting extreme spreads:
1.79”
1.23”
2.44”
for a 10-shot group average extreme spread of 1.82”. 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 0.55”.
The smallest 10-shot group.
https://app.box.com/shared/static/bry07gfc7f80ncsj9ceefmh7simhsiq0.jpg
The 30-shot composite group.
https://app.box.com/shared/static/i3anenfdlyjny90me9zgz8u3oeoi7vs0.jpg
…..