B&T Ammo Labs Fragmentation Experiment #5:

"Multiple Round, High Velocity 5.56mm 75 grain Hornady BTHP vs 77grain Nosler BTHP performance in bare gel."

Tatjana von E. and Derek W. F.

The purpose of this experiment was to compare the wounding properties of the aforementioned rounds in 10% calibrated ballistic gelatin. Given the impressive wounds created by both, and the possibility of a group purchase in which only one round may be chosen, we felt that testing them was of the utmost importance.

Thanks to one member (name withheld until I contact him), we were able to acquire some of the cannelured Hornady 75gr in standard .223 pressure. And thanks to the good people at Hornady that took all my money on a 550B, I was able to load up some 77gr Nosler to the same velocity.

We would also like to thank "Hi_Vel" for the gelatin molds that he manufactured for us in the past. These have become invaluable.

specifics and conditions:

Ammo: .223 75 grain Copper Alloy Jacketed BTHP rounds and 77gr Nosler Copper Alloy Jacketed BTHP rounds.

Rifle: Preban Colt 16" A3 with M4 Profile 1:7 Barrel and Phantom Flashhider.

Temp: 65 degrees. 63% Humidity. Pressure: 30.15 in/Hg. Alt: 213 feet.

The target was a FBI spec block (20x20x50cm) of 10% ballistic gel (9 parts water, 1 part gelatin by weight). Vyse ballistic gel was prepared according to FBI ballistic gel testing protocols. Additionally, gel temperature was not permitted to exceed 37 degrees C at any time during preparation.

Following preparation, gel was stored at ~4 degrees C and permitted to cure for 72 hours before testing. Gel was tested within 15 minutes after removal of blocks from refrigeration. Gel blocks were calibrated with a .177 caliber BB immediately before testing. (Optimum = 8.5cm @ 590 fps). Our results were within accepted calibration standards for ballistic testing without penetration measurement adjustment.

10 velocity tests on each type of round was conducted using an Oehler Research 35P chronograph 15 feet from the muzzle. Results are included below:

75gr Hornady
2616 fps (shown in gel)
2556 fps
2575 fps
2551 fps
2533 fps
2560 fps
2538 fps
2543 fps
2583 fps
2546 fps

Calculations on velocity data:

Mean: 2560
Median: 2574.5
Standard Deviation: 25
Extreme Spread: 83

77gr Nosler
2610 fps
2600 fps
2582 fps
2611 fps
2558 fps
2594 fps
2624 fps (shown in gel)
2594 fps
2596 fps
2616 fps

Calculations on velocity data:

Mean: 2598.5
Median: 2591
Standard Deviation: 18.87
Extreme Spread: 66

After some alignment shots, targets (bare gel blocks) were placed 16 feet from the muzzle and each subjected to a single round. Velocity of the projectile was again measured at 15 feet, 1 foot before the gelatin block.

Multiple blocks were shot.

The blocks were examined, photographed and then dissected into slices. Slices were photographed to measure and record wound profile size. Fragments were then extracted and their penetration depth measured and recorded. Fragments were organized according to penetration depth and photographed to record fragment distribution throughout the wound cavity.

The highest performance (penetration and fragmentation) are photographically reproduced here.

Results notes/Observations:

1. The velocity of the best performers in each category was the highest measured. The 77gr at 2624 fps and the 75gr at 2616 fps.

2. Velocities as over 100 fps SLOWER than a similar round loaded to NATO pressures.

3. Fragmentation of each round was quite dramatic, and both rounds had VERY similar neck lengths at 4cm (1.57"). While this is not as short as we'd like, and doesn't quite compare to the 0.5" neck length of the 100gr round, it is still good.

4. Total recovered weight of the projectiles were:

75gr: 75gr
77gr: 74.2gr

5. Largest recovered fragment (deepest penetrating in both cases)

75gr: 35.6gr
77gr: 32.1gr

6. All of the 75gr rounds veered off in one direction or another, but would have most likely equaled the 77gr in terms of penetration if they had kept a straight course.

7. The nose of each round was sheered off rather quickly in each case. You can identify the fragments in the charts below.

These rounds will fragment at MUCH lower velocities than standard M193 or M855 ammunition will, making them suitable for shorter barreled rifles, or for longer distance shots. Both faired very well, and are just about equals to each other, and definitely outperformed our previous M193 experiments and the M855 data that we've seen. However, we both think that the 77gr Nosler has a larger temporary wound cavity than the 75gr Hornady. However, this could have been due to the slightly increased velocity. However, given that the Nosler *slightly* outperformed the Hornady, we would choose the Hornady over the Nosler due to the possible setback issues inherent in non-cannelured rounds.

Figure A: Left to right: M193, M196, M855, M856, 75gr Hornady BTHP, 77gr Nosler BTHP

Figure B: First section of "High" penetrating 75gr Hornady BTHP in gel

Figure C: Main section of "High" penetrating 75gr Hornady BTHP in gel

Figure D: Last section of "High" penetrating 75gr Hornady BTHP in gel

Figure E: Recovered fragments by depth for "High" penetrating 75gr Hornady BTHP round

Figure F: First section of "High" penetrating 77gr Nosler BTHP in gel

Figure G: Main section of "High" penetrating 77gr Nosler BTHP in gel

Figure H: Last section of "High" penetrating 77gr Nosler BTHP in gel

Figure I: Recovered fragments by depth for "High" penetrating 77gr Nosler BTHP round