Hammer ballistic coefficient tests...

[cohunt]

 

[WiscGunner]

1) Nothing personal, but this type of response is why some people don't trust things said on the internet....

2) Incorrect. Because the B.C. affects the entire flight, a 3000 fps muzzle velocity rapidly becomes a <<<3000 fps as the drag slows the bullet down. Also, for reasons I don't fully understand, and personally find counterintuitive, time of flight has little bearing on wind drift compared to B.C.

Obviously the BC affects the entire flight of the bullet and I didn't say it didn't. "all other things being equal" higher velocity is affected by wind less due to tine of flight.

2 scenarios below, run through JBM Ballistics. Standard atmosphere, 10 mph wind.

153 A-Tip, 2700 fps. 500 yards. 0.632 seconds flight time. Wind drift 13.6". 1000 yards, 1.466 seconds flight time, wind drift 62.8"

124 HH, 3000 fps. 500 yards. 0.620 sec flight time. Wind drift 21.4". 1000 yards, 1.614 sec flight time, wind drift 108.5"

At 500 yards, the A-tip has slightly MORE flight time, but 64% of the wind drift of the 124 HH. At 1000 yards, the flight time is less than the 124HH (90%), but the A-tip has 57% of the 124 HH wind drift.

Wind drift for the slower A-Tip is less than that for the 124 HH from the muzzle onward. Let me repeat that. The higher B.C. bullet drifts less from the start, and only gains more advantage as it goes down range.

Also, the A-Tip passed the 124HH in velocity at 330 yards. From there on out, it has FAR more energy (heavier), and the velocity/wind/energy gap will only widen as it travels down range.

To quote myself again: "High BC retains more velocity down range". I fear you have misread my lost or intent. Velocity does mask as additional BC due to time of flight, how much BC depends upon how much velocity.

3) Incorrect. By your own example "BC does start to play into trajectory by 500 330yards and beyond". Indeed, ~9" of wind for the 124HH and only 6" for the 153 A-Tip at 330.

Again I am well aware of BC's importance throughout the flight time. Higher BC can get away with lower velocity, lower BC needs higher velocity to perform the same…"until that lower BC deteriorates the velocity below the point of gains."

I'm not sure you realize, but the 124 HH, with the carefully circled and highlighted "Calculated" was the bullet that performed the furthest from advertised in my experiments. Indeed, all of the Hammer bullets I tested were labeled as "Calculated from shot drops" on the website.

I am well aware both numbers are inaccurate, just stating they are announcing 2 different metbods of creating their BC numbers which may contribute to why some people have more extreme number issues than others. Nowhere did I vouch for the accuracy of those numbers but if I came off as doing so, thank you for additional clarification.


Comparing BC …all other things the equal

Assuming the BC for the 124HH is correct at .245G7, it requires 50ish% more wind hold compared to a 140ELDM at 600yrds and more for the 153. All going 2700fps in a 15mph wind. Again no claim to the accuracy of the sample BC's used.

Bump the velocity and it maskes as high BC due to shorter time if flight….until that lower BC deteriorates the velocity below the point of gains.

124 @ 3300 as previous posted 6.5prc PRC makes it roughly the same as the 140 Eld-M

Now for the 153 vs the 124…using AB's BC for the 153, additional velocity again makes up for BC. Just need to push the .245 G7 3650fps to match the G7 .359 153gr A-Tip at 600yards.

In conclusion, pushing these lower BC solids to higher speeds does in fact make up for less BC inside medium ranges used in hunting and even makes for a flatter trajectory to help with range estimation errors. (No claim to actual bC value is made here).

Yes everyone should true their own system, yes manufactures should provide resinanly accurate BC information for these sort of projects PRIOR to purchasing expensive components to test.

 

[codyadams]

Not my job to teach mathematics. Lesson concludes with this post.

scdogman has calculated the percent difference of the Litz value from the Hammer BC value. Cody finds that method correct. Fair enough...
If the .313 Hammer BC is the correct BC, you can divide .237 by .313, and then argue the Litz BC is 75.7% the value of the .313 Hammer value. The Litz value is indeed 24.3% different, less than, .313. IF the Hammer BC is correct, the concludion is the Litz value is a 24.3% error from the correct value. All appropriate IF the Hammer value is correct.

But scdogman's post relied on the Litz BC values as the "standard" for comparison, when stating "I don't understand the doubting of the numbers. The numbers are on par with Brian Lutz's calculated g7 results with all his fancy high tech equipment." And... "Brian gets .237 and my 700 to 800 yards drops gives me a 0.241 g7."

If the presumption is the .237 Litz value is the correct value, or the most correct value, the .313 value constitutes a 32% error from the most correct value. And I've presented the correct calculation of that percent difference, albeit the percent error, of the Hammer value from Litz's .237 G7.

IF the .237 Litz value is correct, Cody and scfogman have calculated a 24.3% difference from something. A 24.3% difference from an errant value? A 24.3% difference from a wrong value? That means something to someone?

On the other hand, if the standard for performance is "The numbers are on par", does any percent difference or percent error, calculated correctly or incorrectly, really matter?

Begs the comment "Whatever"...
Whatever your pleasure...

It simply means that the litz value states it has a 24.3% lower bc value than Hammer. Or another way to say it, Hammer states their bc is 24.3% higher than the litz value. The percentage is relative eachother. For me the litz values aren't always right on either, however usually very close and still usually on my 20" tall steel target out to 1000. They are still just another starting point that needs to be verified.

After going back through my log book I have actually stretched out one Hammer bullet, the 7mm 143 hh. The advertised .230 g7 came out true enough to not warrant changing for me to 937 yards from a 9.25 twist 7 mag, using a VX6-HD 3-18 For dialing. I live at 6600 ft elevation, not sure how much that matters, it was factored into applied ballistics. They were right on waterline for me.

I honestly think the only way to get true and consistent published bc's across the board for the purpose of comparison would be if an unaffiliated company had a standardized method and tracked every bullet in existence. AB does just that, with some minor variations. They have pretty tight affiliations with Berger, that may cause some people pause. I can't say if it affects their testing, I personally have no clue. I still use their app. They also don't have all the bullets from smaller or especially newer manufacturers, understandably so. I have heard, though I am unaware if it is true, that they charge a fairly sizeable amount to profile a bullet. Not sure about any details, and I may be wrong.

Again, no dog in this fight. Just throwing out my observations, hoping to remain nuetral.

 

[WiscGunner]

Why not a Long Range Hunting spreadsheet from user verified BC's? Would clearly show trends and averages amongst actual users. Just need a standardized input criteria such as, mV, altitude/temp/humidity or DA, barrel twist, distance, ballistic calculator used, etc.

Simply compiling the known data already in users hands would create quite a list.

I would guess the biggest issue would be standardizing the calculator used. Unfortunately the most common of the 3 types is encouraged to be tweaked more than a meth head.

 

[codyadams]

Why not a Long Range Hunting spreadsheet from user verified BC's? Would clearly show trends and averages amongst actual users. Just need a standardized input criteria such as, mV, altitude/temp/humidity or DA, barrel twist, distance, ballistic calculator used, etc.

Simply compiling the known data already in users hands would create quite a list.

I would guess the biggest issue would be standardizing the calculator used. Unfortunately the most common of the 3 types is encouraged to be tweaked more than a meth head.

This could be useful. Similar to some of the load data spread sheets we have seen, just list the data you said for bullets. Max range confirmed at, muzzle velocity, corrected G7 used, all that stuff.....

 

[Pdvdh]

It simply means that the litz value states it has a 24.3% lower bc value than Hammer. Or another way to say it, Hammer states their bc is 24.3% higher than the litz value. The percentage is relative each other.

Again, no dog in this fight. Just throwing out my observations, hoping to remain nuetral.

As an engineer with a nauseating amount of mathematics courses, I disagree. Disagreement explained:
1) The Litz BC value is indeed, 24.3% different than the Hammer value. And it's 24.3% lower than the Hammer BC value. IF the Hammer value is the correct BC value, then the magnitude of the Litz error is 24.3%, and the error is lower than the correct BC value.

2) On the other hand, the Hammer BC value is 32.1% (not 24.3%) different than the Litz value. It's 32.1% higher than the Litz BC value. IF the Litz value is the correct value, then the magnitude of the Hammer error is 32.1%, and the error is higher than the correct BC value.

The difference between the two BC values is 0.076.
In example 1) 0.076 is divided by the Hammer value, which is the larger numerical BC value. The larger value in the denominator produces the smaller quotient value (24.3 percent difference).
In example 2) 0.076 is divided by the Litz value, which is a smaller numerical BC value. The smaller value in the denominator produces the larger quotient value (32.1 percent difference).

My percent confidence level? 100

 

[scdogman]

I

As an engineer with a nauseating amount of mathematics courses, I disagree. Disagreement explained:
1) The Litz BC value is indeed, 24.3% different than the Hammer value. And it's 24.3% lower than the Hammer BC value. IF the Hammer value is the correct BC value, then the magnitude of the Litz error is 24.3%, and the error is lower than the correct BC value.

2) On the other hand, the Hammer BC value is 32.1% (not 24.3%) different than the Litz value. It's 32.1% higher than the Litz BC value. IF the Litz value is the correct value, then the magnitude of the Hammer error is 32.1%, and the error is higher than the correct BC value.

The difference between the two BC values is 0.076.
In example 1) 0.076 is divided by the Hammer value, which is the larger numerical BC value. The larger value in the denominator produces the smaller quotient value (24.3 percent difference).
In example 2) 0.076 is divided by the Litz value, which is a smaller numerical BC value. The smaller value in the denominator produces the larger quotient value (32.1 percent difference).

My percent confidence level? 100

As an engineer with a nauseating amount of mathematics courses, I disagree. Disagreement explained:
1) The Litz BC value is indeed, 24.3% different than the Hammer value. And it's 24.3% lower than the Hammer BC value. IF the Hammer value is the correct BC value, then the magnitude of the Litz error is 24.3%, and the error is lower than the correct BC value.

2) On the other hand, the Hammer BC value is 32.1% (not 24.3%) different than the Litz value. It's 32.1% higher than the Litz BC value. IF the Litz value is the correct value, then the magnitude of the Hammer error is 32.1%, and the error is higher than the correct BC value.

The difference between the two BC values is 0.076.
In example 1) 0.076 is divided by the Hammer value, which is the larger numerical BC value. The larger value in the denominator produces the smaller quotient value (24.3 percent difference).
In example 2) 0.076 is divided by the Litz value, which is a smaller numerical BC value. The smaller value in the denominator produces the larger quotient value (32.1 percent difference).

My percent confidence level? 100

All things are relative. To present % error, you state how far from the standard. The standard we start with here is the manufacture's numbers. This will be the denominator in all computations. It shows are far above or below something is from the standard or expected out come.

Also you are right, I'm not a mathematician and I didn't stay in a Holiday Inn Express last night. But I do have an engineering degree and I'm 6 hours short of having math degree as well. Next are we going to see which degree is better?

The example below use theoretical valve
which is the expected output. Again the standard is the denominator(number on bottom).

Also anyone can google how to calculate % error. No math degree needed. I think my example about pay is spot on. What you were expecting to get paid is used as the denominator. We express deviation relative to that. I was underpaid by some percentage or I was overpaid by some percent. It's express deviation relative to the expected outcome. Pay or manufacture's bc on box.

 

[Ernie]

Since I will only hunt with Hammers out to about 600 yards, I will probably put my guesstimate between the two, do my drop confirmations, and adjust BC from there.
I am so far from a math or engineers degree, it is not even funny.
Just go shoot, and report your actual findings, then go kill stuff, and give us good stories with pictures

 

[FEENIX]

IBTL!

 

[xsn10s]

 

[Northkill]

Lovin the math lessons guys. Would hate to see your skills go to rust. Iron sharpening iron here. Haha

 

[QuietTexan]

When considering the 300 RUM, integrating the differential of the function's parabolic natural log means that exponential growth in the ballistic coefficient still amounts to less change in the Coriolis factor impacting wind shift than imparted y the longitudinal tidal force on the perfect sphere on a frictionless plane before imparting the subdural hematoma via hydrostatic shock on the unsuspecting doe under the feeder at 37 yards.

 

[blvette75]

It simply means that the litz value states it has a 24.3% lower bc value than Hammer. Or another way to say it, Hammer states their bc is 24.3% higher than the litz value. The percentage is relative eachother. For me the litz values aren't always right on either, however usually very close and still usually on my 20" tall steel target out to 1000. They are still just another starting point that needs to be verified.

After going back through my log book I have actually stretched out one Hammer bullet, the 7mm 143 hh. The advertised .230 g7 came out true enough to not warrant changing for me to 937 yards from a 9.25 twist 7 mag, using a VX6-HD 3-18 For dialing. I live at 6600 ft elevation, not sure how much that matters, it was factored into applied ballistics. They were right on waterline for me.

I honestly think the only way to get true and consistent published bc's across the board for the purpose of comparison would be if an unaffiliated company had a standardized method and tracked every bullet in existence. AB does just that, with some minor variations. They have pretty tight affiliations with Berger, that may cause some people pause. I can't say if it affects their testing, I personally have no clue. I still use their app. They also don't have all the bullets from smaller or especially newer manufacturers, understandably so. I have heard, though I am unaware if it is true, that they charge a fairly sizeable amount to profile a bullet. Not sure about any details, and I may be wrong.

Again, no dog in this fight. Just throwing out my observations, hoping to remain nuetral.

Hi Cody, A quick question what is the AB reference you used. As many have stated need to take the BC with a grain of salt provided by Manufacturers I picked this thread up this morning. I confirm the drops as far out as I will take game. Thanks

 

[xsn10s]

For the record I'm for accurate BC's especially in a long range setting. It only makes sense. I'll still check by shooting but an accurate BC means I'll waste less ammo verifying/ adjusting and will be able to move on to training for actual use.