Hammer ballistic coefficient tests...

[TheSouthpaw]

I have an Oehler 89 which precisely measures BC from velocity and time of flight. The Oehler measures the BC in your particular gun. I've seen them produce different BCs in different guns.

I've measured a few bullets so far and I tested Tubbs' nose ring and it's affect on BC.

I've attached a couple reports for the 250 a-tip, 225 eld-m, 112 barnes matchburner and the 153.5 Berger in a creedmoor.

The only three methods of finding BC that really hold water out to distance are AB Doppler, Oehler systems and truing via measured drops. The problem is finding the AB RV near you and the price of the Oehler.

I will be testing the 124 HH before I head out elk hunting in November.

Is the nose ring DTAC going to be commercially available? What were your observations on it?

Please post the 124HH results when you're done.

 

[parshal]

It is available albeit expensive. It changes BC, sometimes for the better. It causes closed tip bullets to open pretty violently if you cut the ring deep which also negatively affects BC.

 

[WiscGunner]

OP's Point: Published BC's are wrong.

My Point: I don't care that they're wrong, because published BC's will never be accurate enough for the type of analysis required for long range shooting because they lack significant relevant information.

OP's Counter: They could publish better information if they got a Labradar, a Kestral, and an iPhone app.

My Counter: They still would have to provide BC information in multiple velocity windows, multiple barrel twists, multiple lots of things, and at the end of the day it would still never line up close enough to every rifle those bullets are running through.

You: Come along and basically prove my point.

You're proving it because you somehow chose the 264 WM and 7mm-08, and you didn't list barrel twist. Implicit in your argument that the difference in published and actual BC is that YOU are using the same velocity and twists that were used to calculate the BC. You have no idea the variables you're introducing into the calculation because you don't have the original equipment spec. Your drop is a foot off from the published spec, but could be two feet off or four inches off from the originally calculated BC for the bullet because you're shooting it out of a different rifle. The published BC could be 100% correct for a certain equipment combination, it's just wrong for YOURS. And yet, you have no idea how different it is because the relevant information was never given to you.

Still my point: Published BC is irrelevant because it gives the used a sense of false precision since the most relevant variables are not presenting with the information.

It's a tail chase of never enough. The way you short cut that is to do the actual work yourself, then you don't have to care what the BC on the box is or be mad that the dastardly dastards publishing them are 100% on super-cereal on purpose lying to you


You didn't read that correctly, try again. 1mph more accurately. That means reducing an error, not down to 1mph of accuracy, but by 1 mph. What does your 0.5 mil wind hold change to if you run the window from 4.5 to 8mph? Only 1mph worse on each end, if it changes by half a mil the point stands.

And even then, the whole point here is that using box BC is silly because it's almost certainly wrong anyways. Hornady doesn't have better gear to calculate BC, they used equipment closer to what the OP was using to test them. Each of us have to true up the numbers or it's just as bad a blind guess as using FPS off a box of factory ammo.


600 is plenty far enough to be called long range for hunting. Let's be realistic, no one here is super-sniping animals at 1k+ using the BC off the box after only practicing on the 100 yard range

Thank you for clarifying you wind call expectation. Obviously I totally agree that a better wind call is more helpful than what most people focus on such as group size or ES/SD.

However, I think you are over simplifying the lack of importance of a BC or box velocity while over valuing the multitude of variables at play. You are of course correct that BC will change with velocity, muzzle brake, suppressor, crown, barrel twist, chamber concentricity, ammo concentricity, and type of rifling but it is laughable to think a manufacture can't provide relevant data for standard use allowing the customer to compare products and choose what will best work in their rifle BEFORE purchasing and get them on target with a little "truing" NOT creating from the ground up. Obviously EVERYONE "can" create their own data from scratch but no customer accepts this with just about any product. Do hotels provide relatively accurate expectations of room sizes and amenities prior to purchase or do you pay first and then make shift your own bed and toilet out of whatever they provided?

Shooting to the max distance of a velocity minimum is not going to give the same expansion as higher velocity and suggested velocity minimums are just as unreliable as BC and should be verified by the individual or community or manufacture prior to use. However, it is foolish to think it can't or won't be used to compare bullets prior to purchasing and trying.

"Long Range" while relative to the ballistics of the weapon system is often conflated with the comfort level or skill level of the shooter. Type of target (ie moving or stationary or both) also plays a factor. AdD caribou vs bedded mule deer changes the probability of success at the same distances. 600 yards is just inside what most would consider long range with a standard centerfire rifle as environmentals begin to play a role. 400yrd shots don't really need BC info, weather data, accurate velocity, small group size, tight ES/SD when shooting at a 2-3moa target hence why most short range hunters simply use a point blank zero.

Starting data is very easy to provide from manufactures and unfortunately insecurities tend to push so many manufactures to inflate their numbers to boost their sales. Create a new bullet, do what your suggesting the customer do and shoot them out of a standard rifle, reverse the drops, bingo, suggested starting BC for the customer. "Calculating" or "estimating" the BC of a bullet by doubling the standard velocity or using a 38" barrel or 6twist instead of say 10twist as standard for cartridges in that caliber is just dishonest deception.

Box velocity and box BC can be quite accurate for the custom if honest info is provided. Lots of others have gotten on board. Nosler made a significant coarse correction in the BC's calculated on the moon and now iffer realistic starting point numbers. Hornady offers BC and doppler. Berger offers good BC numbers.

Pretty simple to provide a recommended twist and muzzle velocity the BC was shot with. There is absolutely no reason a manufacture can't say a 140gr 6.5 mm bullet going 2900fps in a recommended 1:8twist is xBC. This then gives a customer infor for comparison and purchasing and then a starting point to begin truing to their rifle system.

Hell, if companies don't want to pay Litz or someone else to test there are tons of knowledgeable people on the forums who would do it for fun, just send some free bullets. Results would all be very similar. Look what Sherman and Hammer are doing with crowd sourced load data, why not crowd sourced BC? Forums could do this themselves quite easily, the hadest part is hsving someone lit the data on a spreadsheet.

 

[RockyMtnUT]

I'd hate to see a loud Texan

 

[FEENIX]

I'd hate to see a loud Texan

 

[Hard rock]

I'd hate to see a loud Texan

You probably wouldn't.

 

[WiscGunner]

That's a valid point , that I haven't stated but was in my thoughts , I m sure Steve will chime in on this at some point and explain probably once again how they arrive at their published B.C . I for one have not noticed hardly any wind drift from the 124 gr HH in the 6.5 PRC at 3300 fps at 500 yds with a 15 mph cross wind . Whatever the BC actually is it seems too buck the wind pretty good any thing I would shoot past 200 yds I will verify too establish my own data out too 600 yds . I feel I owe that too the game I'm taking , bullet drop is fairly simple , the wind drift is my main concern. The old saying trust but verify.

Nothing personal but this type of response is why some people don't trust users with the freedom of knowing the BC before purchasing.

Please, if this is old info for you, ignore it. BC does 1 thing for us, cut through the air. This shows as 2 results in our testing, velocity loss and wind resistance…all other things being constant.

The benefit of Hammer's bands is increased velocity from reduced bearing surface and more consistent BC from gun to gun due to engraving pressure having somewhere to move metal.

In your post, you don't mention a measurement of wind deflection at 500yrds, just "not hardly any". Higher BC allows a bullet to cut through the air, including the wind, with less resistance than lower BC. This resistance includes wind deflection the same as crossing a river. A lower Bc bullet like the 124HH will have far more wind deflection than say a 153 A-tip…all other things being equal. High BC retains more velocity down range.

Jacking the velocity of the 124 over the 153 simply shortens the time of flight thus the amount of time the wind has to deflect the bullet trajectory…acting like the bullets "bucks more wind". 3000fps to 1000yrds (3000ft) should be 1second of flight time. 3300fps is like shooting 900yrds of wind affected distance to 1000yrds. Compared to a 2700fps bullet that is almost like your target being 200yrds closer than the slow guy regarding wind deflection. Cut that in half to 500yrds and the wind doesn't have much time to affect the bullet path. BC doesnt really START to play into trajectory until about 500yrds and beyond. In short, the higher velocity achieved with Hammer bullets helps to offset the lower BC at medium ranges…until that lower BC deteriorates the velocity below the point of gains.

 

[WiscGunner]

For those that haven't noticed, it might be important to point out before people get to bent, Hammer list 2 different types of BC on their website. This is likely why you see some people happier with their factory BC than others. Caution as to what others are doing but at least Hammer is transparent that some are a guess and others are tested in some way.

.264 124gr Hammer Hunter

.284 155 Hammer Hunter

 

[entoptics]

1) Nothing personal but this type of response is why some people don't trust users with the freedom of knowing the BC before purchasing...

2) ...Jacking the velocity of the 124 over the 153 simply shortens the time of flight thus the amount of time the wind has to deflect the bullet trajectory…acting like the bullets "bucks more wind". 3000fps to 1000yrds (3000ft) should be 1second of flight time. 3300fps is like shooting 900yrds of wind affected distance to 1000yrds...

3)...BC doesnt really START to play into trajectory until about 500yrds and beyond. In short, the higher velocity achieved with Hammer bullets helps to offset the lower BC at medium ranges…until that lower BC deteriorates the velocity below the point of gains.

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.

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.

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.

For those that haven't noticed, it might be important to point out before people get to bent, Hammer list 2 different types of BC on their website. This is likely why you see some people happier with their factory BC than others. Caution as to what others are doing but at least Hammer is transparent that some are a guess and others are tested in some way.

.264 124gr Hammer Hunter
View attachment 392862

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.

The fact is, B.C. starts to come into play depending on each individual's needs. 44 mag carbine on deer? 375 Cheytac on steel? There's no rule of thumb, let alone hard and fast number. Suggesting the only way to figure this out is to "try after you buy" is disheartening.

Edited to avoid the % less vs % of sloppiness in language @FEENIX and @cohunt justifiably corrected me on, and I still used again...

 

[scdogman]

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. The hammer i shoot more often is the 177 hh with -.313 g7. Brian gets .237 and my 700 to 800 yards drops give me a .241 g7. 8 twist runnning 3129 fps at 600 ft.

I'm a hammer user in a 4 guns, but the numbers are what they are. If you are shoot 500 yards or in, it doesn't really stand out.

 

[Pdvdh]

Deleting a duplicated post.

 

[Pdvdh]

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. The hammer i shoot more often is the 177 hh with -.313 g7. Brian gets .237 and my 700 to 800 yards drops give me a .241 g7. 8 twist runnning 3129 fps at 600 ft.

I'm a hammer user in a 4 guns, but the numbers are what they are. If you are shoot 500 yards or in, it doesn't really stand out.

Trying to understand your post;
"Brian Lutz"... does that mean "Bryan Litz"? The ballistician that authors the Applied Ballistics books?

The Hammer Hunter you refererence is the .284 177gr Hammer Hunter, correct? I see Hammer Bullet's website assigns a "G7-BC=.313 estimated" to that specific bullet.

Presuming the info I've supplied in question form, above, is correct;
You've posted that you "... don't understand the doubting of the numbers. The numbers are on par with Brian Lutz's calculated g7 results ..."

0.313 is 32% higher than Litz's 0.237 value. And 29.9% higher than your bullet drop-based value of 0.241? You feel the ~31% differences are on par with each other, correct?

 

[bigngreen]

If I remember right Steve has been trying to get his hands on some higher end equipment for getting tighter BC numbers, I don't think it's something not on their mind BUT I think their putting money/time into what is important to their business which is quite obviously not modeled around BC but terminal performance which is where they are spending their precious R&D dollars.
I've shot some screamer BC bullets that frankly sucked a big one when they landed, ya they were fun to shoot but when you open up a rib cage and see more luck in the kill than bullet performance it takes the edge off that. Do I like a BC number I just pick it off the menu in AB, sure but frankly now that we have such excellent chronographs figuring out the BC doesn't even make me think twice especially when it's plain as day on the we site their calculated or drops, I know what that means, same thing as it has for 20 years. Eventually each company has been able to push resources to refine many aspects of their bullets and marketing, I spent a number of years shooting a lot of bullets to figure out the trajectory when even a decent velocity had to be figured out from many shots and conditions, I'm OK shooting maybe 10-20 rounds to tune a BC now days.

I can't count the times I've adjusted the BC on the same Berger bullets and BC is a huge part of their marketing, over time everyone refine.

 

[QuietTexan]

Man, all of these feels over me ignoring manufacturers information. Just slings and arrows y'all. Proof that unpopular ideas get stronger reactions than anything else.

For anyone wants accurate information and doesn't want to do their work themselves, just go buy the CDMs from AB and then you have independent, third-party information without having to go through the manufacturer or put any effort into it.