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| If you are LE or active military call Hornady directly (# is on their website) and ask for LE sales (Kathy). If not, get one of your friends/family in LE or active military to do it. Basically direct from Hornady to LE (individual or department) or active duty military is the only way it will leave their warehouse. |
You should never try to solve your problems with handguns. Large caliber automatics work much better.
Okay... sounds good.. any idea how much it costs? I'm going to make a guess around $0.75 a round  .
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LE pricing is $10.73 for a box of 20 and I think that you get a 10% discount if you order 200 rounds. |
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Stability Test – final results After testing the TAP loads at 50 yards for signs of instability I continued the testing from 100 yards. As stated in the preliminary results post, this test uses a Colt 16” HBAR with a 1:9” twist and is chrome lined and NATO chambered. Before getting to the results I’d like to mention a couple of points as suggested by wyv3rn. First of all, not all 1:9” twist barrels are exactly one turn in nine inches. Some might be slightly faster, such as a 1:8.8” twist and some might be slightly slower, such as a 1:9.2” twist. The point being that your 1:9” twist barrel might be a little different than mine and therefore your stability results may also differ from mine. Secondly, rotational stability is influenced by ambient temperature. A round that is stable on a nice sunny summer day might not be so in the middle of winter. On to the test results. Before firing the TAP rounds, I obtained a 10-shot control group using Sierra 52 grain MatchKing bullets. The group measured 1.01” and had a mean radius of 0.36”. This group is a fine example of the accuracy this barrel is capable of as I have duplicated these results numerous times in the past with this barrel. Here is a pic of the control group.  First up for the TAP loads was the TAP FPD load. You may recall this load showed excellent accuracy when fired from a 1:7” twist barrel. Using the Colt 16” barrel with the 1:9” twist I obtained three 10-shot groups from 100 yards that measured: 1.28” 1.65” 1.76”. For comparison the three 10-shot groups of the TAP FPD load fired from the 1:7” twist barrel measured: 1.08” 1.15” 1.18”. Using my usual procedure of overlaying three 10-shot groups on each other using RSI Shooting Lab software I obtained a 30-round composite target of the rounds fired from the 1:9” twist barrel. The mean radius for this target was 0.48”. By comparison, the mean radius of the 30-round composite target for the TAP FPD load fired from the 1:7” twist barrel was only 0.37”. This shows a definite increase in group size for the rounds fired from the 1:9" twist barrel.  Next, following the same procedures, I obtained three 10-shot groups of the 5.56 TAP load through the 1:9” twist barrel that measured: 1.44” 1.90” 2.06”. For comparison the three 10-shot groups obtained from the 1:7” twist barrel measured: 1.16” 1.38” 1.45”. As before, 30-round composite targets were compiled to compare the mean radii. The mean radius from the 1:9” twist barrel measured 0.54” while the mean radius from the 1:7” twist barrel measured 0.46”. Again we see an increase in group size for the rounds fired from the 1:9” twist barrel. (Keep in mind that the control group from the 1:9” twist barrel was right on par with the control groups from the 1:7” twist barrel.)  All the bullet holes from both TAP loads were typically rounded bullet holes. There was no sign of key-holing whatsoever. However, with both the TAP FPD and the 5.56 TAP we are seeing an obvious increase in group size when fired from the 1:9” twist barrel (although in practical terms the increase in group size is less than one inch from the smallest TAP FPD group fired from the 1:7" twist barrel to the largest 5.56 TAP group fired from the 1:9" barrel at 100 yards.) Obviously, test results from just one barrel with a 1:9” twist don’t prove anything and it could be that my barrel just doesn’t like the 75 grain bullets. However, I think the results suggest that the TAP rounds were only marginally stabilized in the 1:9” twist barrel under the ambient conditions and that is the reason for the decrease in accuracy compared to the 1:7” twist barrel. Feel free to post your conclusions. Atmospheric conditions: Temperature: 76 degrees F Relative humidity: 39% Barometer: 30.19 Elevation: 960 feet above sea level |
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Molon- I assume your 1/9 barrel is chrome lined? I have always wondered if the chrome lining would lead to less spin and stabilty - less friction. Also, as a barrel wears out the rifling and ID wear as well. Just my random thoughts and like you said..everyones barrel is a little different. Would a slower round (non-5.56) have a chance to stabilize better. Since it is not be forced down the barrel as hard/fast? Thanks for the posts! Edit- I am wondering if a barrel and its rifling can only do so much work towards stabilizing a bullet. If their was an equation it would be something like bullet weight times energy times twist coefficient for barrel = a certain spin rate required to keep the bullet stable. Therefore increasing bullet weight and/or speed down the barrel could throw of the equation for a stable bullet...Just realized that their probably already twenty equations out their to figure this stuff out.  |
The Greenhill formula for rifling twist is as follows: For velocities up to about 1800fps: Twist = (150 * bullet diameter) / (bullet length / bullet diameter) For velocities above 1800 fps: Twist = (180 * bullet diameter) / (bullet length / bullet diameter) This formula is not super-exact, as it does not take into account bullet shape, jacket material, jacket thickness, bullet density, etc, etc, but it is a great starting point and is very simple, whereas an all encompassing formula would be much more difficult to use quickly. Sir Alfred Greenhill (1847-1927) came up with the formula. He was a lecturer in mathematics at Emmanuel College, Cambridge, England from 1873-1876. He also taught mathematics to artillery officers at Woolrich Military Academy from 1876-1906. |
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MK262 comparison As far as I am aware, the only other 5.56mm NATO pressure round loaded with a “heavy” OTM bullet besides the Hornady 5.56 TAP round (that is currently commercially available) is the Black Hills MK262 load. One can’t help but wonder how the two compare. The MK262 round is currently loaded with the Sierra 77 grain MatchKing bullet with a cannelure. Looking through my chronograph records shows that the MK262 round has a slightly higher velocity compared to the 5.56 TAP round when fired from a 20” NATO chambered barrel and nearly identical velocities when fired from both 16” and 14.5” barrels. The overall standard deviations of both loads are also quite similar.  The external ballistics of the two loads are virtually indistinguishable out to 250 yards. The conservative ballistic coefficients used for the graph and tables below were derived by testing at 200 yards by Rick Jamison.    I tested the accuracy of the Black Hills MK262 load using the same Colt 20” HBAR that was used to test the Hornady 5.56 TAP load. This barrel is NATO chambered, chrome lined and has a 1:7” twist and has repeatedly proven to shoot very well for a factory barrel. (While a match barrel, with say a Wylde chamber, might produce tighter groups than this barrel, the idea here was to test the MK262 load for its relative accuracy compared to the 5.56 TAP load.) The testing was done from a bench-rest at 100 yards. My usual procedure of obtaining three, 10-shot groups from 100 yards and overlaying those groups on each other using the RSI Shooting Lab software program was continued with this test. The previous control loads fired from the Colt HBAR using a standard handload with a 77 grain Sierra MatchKing had a mean radius of 0.32” for the 30-round composite target. The 30-round compostite target from the MK262 load produced a mean radius of 0.42”. For comparison the mean radius of the previous 30-round composite target from the 5.56 TAP load was 0.46” giving the MK262 load a very slight edge in accuracy. The 10-shot groups measured: Control load---1.05”, 1.07”, 1.10” MK262---------1.20”, 1.34”, 1.37” 5.56 TAP------1.16”, 1.38”, 1.45”  |
| Good Job Molon! This stuff needs to go in a tacked thread as it's asked about every month or so. |
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"All Arfcommers should wear thier multicam smoking jackets or jammies around the house in anticipation of JBT tasering/dog shooting/civil rights violation or the occasional impromptu gangbanger street theater." - m24sh
"All Arfcommers should wear thier multicam smoking jackets or jammies around the house in anticipation of JBT tasering/dog shooting/civil rights violation or the occasional impromptu gangbanger street theater." - m24sh
Thanks for pointing out the misprint. The chart has been corrected. Naturally not all of my chronographs came out so close to each other. I thought it was remarkable that I was able to find those occurances that were so nearly identical. Also, the velocity figures I posted were from the MK262 load using the Sierra OTM bullet. The MK262 from the original AR-15 group buy that used the Nosler OTM bullet tended to have slighty higher velocities out of a 20" barrel. I don't save the extreme spread figures in my computer database of chronograph data, but if I can find the original chronograph printouts I'll post that data. |
I suspect, according to the data and pics, that the MK262 and 5.56 TAP use the IDENTICAL ball powder. I would sure like to know for my TAP/MK262 handload clones...  So far I have been unable to find a duplicate from available RETAIL powders.  Rmpl 
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"Our destruction... will be from another quarter. From the inattention of the people to the concerns of their government, from their carelessness and negligence..." ...Daniel Webster, June 1, 1837
What Would Yahshua Do? www.wwyd.org
What Would Yahshua Do? www.wwyd.org
I'm certainly no ammo guru, but perhaps the factory blends are proprietary? May not be able to duplicate with retail stuff. YMMV. |
When the going gets tough...the tough go cyclic.
The 75 grain TAP FPD and 75 grain "practice" loads both use the same "T1" bullet and have similar muzzle velocities and therefore nearly identical trajectories. 75 TAP FPD muzzle velocity = 2638 fps 75 "practice" muzzle velocity = 2646 fps 75 5.56 TAP muzzle velocity = 2821 fps  
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Here is another perspective on how accurate the 5.56 TAP round is for a NATO pressure load. Below is the 30-round composite target of the 5.56 TAP load fired from 100 yards compared to a 30-round composite target of IMI M193 fired from the same Colt HBAR at 100 yards. The composite mean radius for the M193 load is 0.72" while the mean radius for the 5.56 TAP load is only 0.46". Here is the same 30-round composite target from the 5.56 TAP load overlayed on an NRA High Power type target reduced for 100 yards. (The X-ring measures 1.5" and the 10-ring is 3.5".) 
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| Not to mention, IMI M193 is about tops in consistency & accuracy as M193 goes. I've seen much worse accuracy out of other M193 and M855. What was the max spread on the IMI? I'm guestimating somewhere around 2.5" for the entire 30 round group. That's as good as M193 gets. Milspec requirement is something like 4-5". |
You should never try to solve your problems with handguns. Large caliber automatics work much better.
The individual 10-shot groups of the IMI M193 measured 2.24", 2.59" and 2.62". The extreme spread for the 30-round composite target was 2.88". The IMI stuff is the best M193 that I have come across. |
1911. I've heard rumors there are other handguns
Joined:
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Posts:
3533
EE: 100% (37)
FL, USA
1911. I've heard rumors there are other handguns
Joined:
Sep 2005
Posts:
3557
EE: 100% (37)
FL, USA
group buy 
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Psalm 54:7 For He has delivered me from all my troubles, and my eyes have looked in triumph on my foes. yep <img src=/images/smilies/icon_smile.gif border=0 align=middle>
DaveS: The Holy Spirit and a 1911 are good companions.
DaveS: The Holy Spirit and a 1911 are good companions.
| There are already people willing to purchase ammo for us in group buy fashion for the 5.56 TAP load. However many of the people I have talked to about this want prices below dealer cost and below LE cost or at most they want people to go through a lot of crap for zero benefit just because they are selfish and dont want the officer doing the order for them to benefit in any way. "LE cost is $110 per 200 and I dont want to pay more than that even if I am not LE" |
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Molon, This among the best publicly available testing of this type I've seen done; you are to be congratulated! Your results are in concordance with both testing we have conducted and other data that I am aware of. Thank you for your efforts at making this useful information openly available and helping to educate the shooting public. |
I couldn't have asked for a better validation of my results. I thank you kindly. Molon |
1911. I've heard rumors there are other handguns
Joined:
Sep 2005
Posts:
3629
EE: 100% (37)
FL, USA
Indeed, the tackage is strong with this thread ... |
Psalm 54:7 For He has delivered me from all my troubles, and my eyes have looked in triumph on my foes. yep <img src=/images/smilies/icon_smile.gif border=0 align=middle>
DaveS: The Holy Spirit and a 1911 are good companions.
DaveS: The Holy Spirit and a 1911 are good companions.
Probably a good idea. |
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