Hi guys,

Here is part of the requested TAP data. It will take several posts to cover all info so bare with me....

First the rifle test protocol:
Velocity is measured using a Oehler 35P at 21 feet from the muzzle.

Max performance distance is based on bullet-retained velocity at distance and the associated expansion, fragmnetation and penetration performance at that velocity. The distance given indicate the point out to which the terminal performance will closely match that shown in these test results.

Media: 10% ballistic gelatin was prepared in accordance with the procedure outlined by dr Fackler and mr Malinowski in their article "Ordnance gelatin for Ballistic studies", The Journal of Forensics and Pathology 9(3): 218-219 1998. Blocks measured 6"x10"x12" and stored at 40 degrees Fahrenheit until just prior to testing. Calibration was done with a BB fired at 585-610 fps with a depth of penetration of 3.1 to 3.9 inches. Gelatin was placed 30 feet from the muzzle of the test weapon.

Location:
Hornady Manufacturing Ballistic Laboratory Grand Island, Nebraska.
Elevation:
1800 feet ASL
Temp:
74 degrees Fahrenheit

Weapon: SIG 551
Barrel: 14.5 inches
Twist rate: 1/7

40 TAP @ 3257 fps
tot. pen. 5.25"
max. temp. cav. 5"
dept to max. cav. 2"
entry .25"
retained weight 0 gr.
max performance range: N/A

55 TAP @ 2767 fps
tot. pen. 7"
max. temp. cav. 5.13"
dept to max. cav. 2.75"
entry .5"
retained weight 0 gr.
max performance range: 240yds

60 TAP @ 2694 fps
tot. pen. 9"
max. temp. cav. 5.25"
dept to max. cav. 2.5"
entry .5"
retained weight 15.8 gr.
max performance range: 215yds

75 TAP @ 2518 fps
tot. pen. 11.75"
max. temp. cav. 4.88"
dept to max. cav. 3.5"
entry .75"
retained weight 37.4 gr.
max performance range: 125yds

Rgds,
Bollocks

Weapon: Steyr USR
Barrel: 20 inches
Twist rate: 1/9

40 TAP @ 3454 fps
tot. pen. 5.13"
max. temp. cav. 5"
dept to max. cav. 2"
entry .5"
retained weight 0 gr.
max performance range: N/A

55 TAP @ 2944 fps
tot. pen. 7.13"
max. temp. cav. 5"
dept to max. cav. 2.68"
entry .25"
retained weight 12.6 gr.
max performance range: 300yds

60 TAP @ 2832 fps
tot. pen. 8.63"
max. temp. cav. 5.25"
dept to max. cav. 2.68"
entry .25"
retained weight 20.5 gr.
max performance range: 275yds

75 TAP @ 2653 fps
tot. pen. 13.63"
max. temp. cav. 5.25"
dept to max. cav. 6.38"
entry 1.68"
retained weight 31 gr.
max performance range: 225yds

Rgds,
Bollocks

I put this Colt in because of the 1/12 twistrate and the effects on terminal performance:

Weapon: Colt AR15 A1
Barrel: 20 inches
Twist rate: 1/12

40 TAP @ 3513 fps
tot. pen. 5.75"
max. temp. cav. 4.25"
dept to max. cav. 2.38"
entry .25"
retained weight 0 gr.
max performance range: N/A

55 TAP @ 3030 fps
tot. pen. 7.75"
max. temp. cav. 4.75"
dept to max. cav. 2.25"
entry .5"
retained weight 0 gr.
max performance range: 300yds

60 TAP @ 2909 fps
tot. pen. 9.13"
max. temp. cav. 4.25"
dept to max. cav. 3.5"
entry .5"
retained weight 21.6 gr.
max performance range: 275yds

Rgds,
Bollocks

And here is the AR15 with fast twist rate:

Weapon: Colt AR15A2
Barrel: 20 inches
Twist rate: 1/7

40 TAP @ 3535 fps
tot. pen. 6"
max. temp. cav. 5.12"
dept to max. cav. 1.87"
entry .25"
retained weight 0 gr.
max performance range: N/A

55 TAP @ 2997 fps
tot. pen. 6.75"
max. temp. cav. 4.75"
dept to max. cav. 2.25"
entry .5"
retained weight 8 gr.
max performance range: 300yds

60 TAP @ 2937 fps
tot. pen. 7.43"
max. temp. cav. 4.68"
dept to max. cav. 2.5"
entry .5"
retained weight 8 gr.
max performance range: 275yds

75 TAP @ 2663 fps
tot. pen. 11.87"
max. temp. cav. 4.87"
dept to max. cav. 5.62"
entry 1.12"
retained weight 37.4 gr.
max performance range: 225yds

That's it for now,
I hope you like it...

Cheers,
Bollocks

Thanks!

Hi,

I can't believe Maddog is the only reply I get on this thread......While everybody sounded so interested.....

I think I'll skip posting the rest of the data as it is a tedious job...Or is somebody still interested??

Cheers,
Bollocks

Please continue posting.  I really appreciate it.  Many people read your posts but only a few actually respond.  Keep it coming!!!

The data is interesting but why a post for a 20" USR, 20" AR 1:12, and 20" AR 1:7?

Its been shown (repeatedly) twist rate doesn't appreciably effect terminal performance.  This can also be seen in your data of the 20" ARs.  

It is interesting to note the velocity differences of the 3 weapons tested - lots of velocity variance in those loads; or is the rifle?  The USR always seems to have the slowest velocity and its a significant loss.

I'm kind of curious about the max performance distance of the 75gr Hornady. If you plug the numbers given into a ballistics calculator, the ranges given don't sync up too well.

It suggests a velocity floor of anywhere from 2149fps (20" 1/9 USR) to 2244fps (14.5" 1/7 SIG) for terminal performance.

That doesn't sound like a big difference; but it is the difference between a 185yd effective performance and a 225yd effective performance.

Yes, Please continue posting.

Thanks for the replies guys! I just needed to know if my effort was appreciated. When time permits I'll post some more stuff.

BTW. Please note that these are tests done by Hornady. I'm just the messenger. I also have ??with some of the data, but please direct your questions to Hornady.

I included the USR, AR15 1/7 and AR15 1/12 because Hornady did. With the 55 and 60TAP data you can clearly see the 1/12 penetrates deeper, especially with the 60 grainer it's striking. Wether this is conincedence, I don't know. I just deliver the raw data.

It's a fact btw that Steyr AUG/USR barrels are 'slower' than AR15 barrels. Why? You tell me, but I noticed that on several occasions where I measured velocities of ammo/reloads in different 223's. The HK's in 223 loose even more speed. A 16 inch AR15 barrel is faster than an 18 inch HK93 barrel with the same ammo.

Concerning the whole trauma-ballistics discussion, I don't want to get into that because I approach this subject from a complete different angle,....but who cares.

I'm still very thankfull that there are individuals on this site (Troy, Tatjana, Brou et al.) who sacrifice their time/money/dedication to perform all these experiments for us lot! I don't care too much for a number of the conclusions, but I LOVE the RAW data!

Cheers,
Bollocks

Agreed!!

Please continue posting!

I was just sitting down to do that myself-  Just looking at their numbers, it looks like the 75 gr. TAP will extend your reach ~10-20 meters over M193 in a similar barrel length.

(Wild Assed Non-Scientific Guess)

Bollocks-
  Thanks for taking the time to post all this- One request- Did the booklet have any data for shorter barrel lengths (10.5-11.5")?
Thanks!
 

What is "entry" measuring?

Someone feel free to correct me if I'm wrong; but my guess was that it was measuring distance to yaw after entry in ballistic gelatin.

Could you post the data for 75gr out of a 20'' AR15 1 in 9 twist?

Oz