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Hammer ballistic coefficient tests...
- Thread starter entoptics
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entoptics
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@JD284win
I'm astonished that your real world data put the B.C. ~25% lower than whatever method Hammer is using to provide their B.C. estimates, hence my thought that maybe it was a typo. Thanks for confirming.
I used LabRadar and JBM to back calculate the B.C., not shot drop validation.
@Hugnot
I believe JBM uses the same "algorithm" it would use to calculate downrange velocity in a normal ballistic solution, but instead solves for B.C. by using your velocity inputs and the distance between them. Essentially it just re-arranges the equation to use inputs of distance/velocity to solve for B.C. instead using inputs of velocity/B.C to solve for a series of distances.
I'm sorry you "take exception". I have no dog in any fight. I'm simply providing information.
I would like to point out a few things that I think you are overlooking in your "apples to oranges" statements.
1) The most liked posts in this thread say something along the lines of "verify for yourself". That implies that relatively primitive and low cost methods can be used to arrive at a useful B.C.
2) If "all rifles are different" is meaningful at the variances we're seeing (it's not), then one would expect some to report higher than quoted B.C.s, and some to report lower than quoted B.C.s. We don't see that.
3) I've seen numerous posts on Hammer B.C.s, arrived at with primitive/inexpensive methodology, and not a single one was actually higher than that quoted on Hammer's product page.
4) Many of Hammer's quoted B.C. values (and apparently Cutting Edge, Badlands Precision, et al.) are calculated from "shot drops", yet they aren't collecting Doppler files from a LabRadar in conjunction with an iPhone and Kestrel, despite the low cost.
5) With my $750 setup (LabRadar + Kestrel), I've gotten results which are within 8% of every "large long standing bullet manufacturers that have greater resources for a longer period..." I've tested. Most are within 5% or less.
xsn10s
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I appreciate the work as LR shooters have adjust BC's to fit their trajectory vs manufacturer's published BC's. This has been pretty common and the extra equipment used only adds more accuracy to the "calculated" BC's. IMO all BC's are calculated. Hornady even has a BC page with barrel twist differences on their BC's. Keep up the good work and thanks for sharing your results.
buckbrush
Well-Known Member
My experience with the 124 HH and the 125 Badlands SB II are very close to this regarding BC variation. Actual being less than advertised by about the same margin.
I use and LabRadar and MagnetoSpeed in tandem.
I use and LabRadar and MagnetoSpeed in tandem.
WiscGunner
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- Aug 2, 2016
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I tested the 155 (158) Hammer Hunters in my 7SS 1:8" Proof CF 26" barrel. Dead nuts clover leaf impact splashed on rick face at 763 yard… drops not remotely lined up with BallisticARC or AB (same base math) using factory g7 BC of 0.259. Tried AB's G7 BC 0.206 and was closer but not great. Switched to Trasol with AB's BC number and dead nuts. Same was true with Hornady 180gr at further distances. Common calculator formulas don't match real drops very well especially as BC deteriorates with velocity. Trasol doesn't rely on BC as the main determining factor in its calculations. A little frustrating the factory BC is so much off from common usage but thrilled with the laser accuracy of the bullets!
I definitely agree with all of that and take away pretty much the same things.
If I may, I only want to offer some more considerations to this thread topic. I'm not implying anything and I'm not trying to pick a fight against anyone or any specific bullet.
Some things are extremely hard to model and calculate, such as drive bands, bore riders, amount of drive bands, rounded edges, open tips, size of open tips, exposed lead tips, etc, etc. Fir those things, you have to simply look at the drop data, radar data, etc and extrapolate it from that by comparing them all to see what makes a positive or negative effect on aerodynamics and BC.
I had a conversation not too long ago with Bryan Litz about drive bands, to include Hammer's drive band design, and if he'd ever tested the same things when they were designing the Berger Match Solids. Even with a patent, it won't stop you from at least doing tests to see the effects. Here was his main response in regards to it:
So from that conversation, and based on the data presented in this thread, I think it's safe to say that while the drive bands and rounded edges of the Hammers do indeed help achieve great MVs and reduce drag compared to if they didn't have the radiused edges, the amount of grooves used still lowers the overall aerodynamics and greatly increases parasitic drag. Thus, actual BC will be significantly lower than any estimate. The open tips compound this as well.
Again, I'm not trying to use this as some way of saying "Hammers are bad". I'm only offering it as data and talking points and as a contributing factor on the actual BCs seen by many with them and how they seem to consistently be lower than all the published estimates.
I do wish more bullet manufacturers would invest in such things as switch barrel action setups so they can cost effectively test many different bullets and in many different rifle twists and velocities, as well as inexpensive radar like LabRadar, teamed with software like the RSI Shooting Lab software, to be able to get much more accurate BCs for the consumer to start with. Even a LabRadar, or Magnetospeed, and a Kestrel with AB software and doing drop verifications like @entoptics has done here is effective as well as cost effective.
Just wanted to share those thoughts, as it's been eating away at me since the start of this thread. I'm not trying to stir any pot here, so please don't take my intentions the wrong way.
Here's a link to that RSI software too, if anyone was interested and wondering about it:
RSI’s Shooting Lab Ballistic Software for Hunters & Competitive Shooters
Comprenensive ballistics, records & analytical shooting software for Hunters, Reloaders & competition shooters.
www.shootingsoftware.com
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No, I understand completely what you did and how. Its the comparison of well established bullet companies with dedicated ballistic resources to a very young almost considered startup company. You did one heck of a great write up, not disputing that one bit. My term exception was not meant relative to the actual work you did. My apologies for that misstatement and resulting misunderstanding.
My comments are not a Hammer defense but is simply an observation of the group in the study.
As you stated, there are a lot of other companies similar to Hammer that do not use a LabRadar or comparable. How they arrive at their BC's from shot drops and resulting "suggested" BC's will have better consistent, comparable results of a common group. My apples to oranges comment is simply comparison of the maturity of companies, size of the companies and their resources to one that has been in business 6 years and still in the "growth" curve.
IMO, a study on similar companies that may be in same boat for resources would be a better analysis of how each one of them calculate their BC's and the perceived "accuracy" therein.
How many shots per bullet to provide a reasonable BC for each bullet. A data point for how much time it took for you to perform this work. Portal to Portal unless you have your own range plus actual total time to conduct each one of the calculations. I think this is an interesting data point as well. This may even be the most telling data point in the study. This will provide an insight into resources required to perform BC testing for their portfolio of products.
For example, CE has about 350 bullets in their portfolio, Hammer has about 240 bullets, Badlands Precision about 35. What time and costs can be associated conducting this work? How much does it cost to farm this work out?
Personally, I would prefer a third party analysis to derive BC's of any bullet. Even then, its a suggested starting point for setting your shot drops.
My comments are not a Hammer defense but is simply an observation of the group in the study.
As you stated, there are a lot of other companies similar to Hammer that do not use a LabRadar or comparable. How they arrive at their BC's from shot drops and resulting "suggested" BC's will have better consistent, comparable results of a common group. My apples to oranges comment is simply comparison of the maturity of companies, size of the companies and their resources to one that has been in business 6 years and still in the "growth" curve.
IMO, a study on similar companies that may be in same boat for resources would be a better analysis of how each one of them calculate their BC's and the perceived "accuracy" therein.
How many shots per bullet to provide a reasonable BC for each bullet. A data point for how much time it took for you to perform this work. Portal to Portal unless you have your own range plus actual total time to conduct each one of the calculations. I think this is an interesting data point as well. This may even be the most telling data point in the study. This will provide an insight into resources required to perform BC testing for their portfolio of products.
For example, CE has about 350 bullets in their portfolio, Hammer has about 240 bullets, Badlands Precision about 35. What time and costs can be associated conducting this work? How much does it cost to farm this work out?
Personally, I would prefer a third party analysis to derive BC's of any bullet. Even then, its a suggested starting point for setting your shot drops.
the444shooter
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- 730
From the Peanut Gallery, I understand the energetic defense and also the criticism of Hammer, as it has been in the spotlight a LOT the last few years, and for seemingly good reason(s)--ease of finding a load, performance on game, responsiveness and helpfulness of Steve himself.
My perspective has always been that they're not going to have a high BC because A) they're not tipped, B) they're mono C) they've got drive bands, and so I compare them mostly to Barnes TSX bullets, albeit they look a little sleeker. No one has ever accused a Barnes TSX of being a high-BC, long range bullet. The main difference being that Hammers appear to open better at distance/lower velocity with a larger cavity.
As I finally took the plunge and ordered some Hammers, I'm entering into it with the mindset that it will most likely be a 500yd max range for me, and I was going to split the difference in BC to test my drops. I'm under no illusion that these are a high-BC bullet, but I do agree that every effort must be exhausted to come out with BCs as close as possible. No manufacturer is immune to that expectation.
My perspective has always been that they're not going to have a high BC because A) they're not tipped, B) they're mono C) they've got drive bands, and so I compare them mostly to Barnes TSX bullets, albeit they look a little sleeker. No one has ever accused a Barnes TSX of being a high-BC, long range bullet. The main difference being that Hammers appear to open better at distance/lower velocity with a larger cavity.
As I finally took the plunge and ordered some Hammers, I'm entering into it with the mindset that it will most likely be a 500yd max range for me, and I was going to split the difference in BC to test my drops. I'm under no illusion that these are a high-BC bullet, but I do agree that every effort must be exhausted to come out with BCs as close as possible. No manufacturer is immune to that expectation.
Right. Transparency is key and not being misleading. Barnes are indeed not a high BC bullet either. There are indeed inherent factors that make a mono less aerodynamic, especially if made to perform well terminally for hunting applications.
I have ZERO issue with Hammers, or any other bullet, being low on BC compared to other bullets. It is what it is. The terminal performance is priority one, with getting it accurately to POA/POI being a very close second priority.
BC factors into priority two, but doesn't really matter if the bullet doesn't behave acceptably regarding terminal ballistics.
What this boils down to is, BC is what it is and that's whatever. What would be more helpful to the consumer is a more accurate figure to start with so their initial decision on what bullet they choose is more accurately made, and their time developing and truing that load is spent productively and efficiently.
No one wants to buy a bullet that looks good on the website, then work up a load and have to go through several components to find out the advertised BC is way off, the bullet is now not going to be as effective to as far as they thought, will require more wind drift correction, etc, etc.
There are many manufacturers that are guilty of misleading BCs. Hammer was just the one that stood out in the OP. I have several examples from ALCO that are a worse example of inaccurate published BC. That's been frustrating too, even knowing about it before buying them.
I get your point you're trying to make too, @Muddyboots with the startup companies. Not all startup companies are using estimated BCs though. Hopefully it's ok for me to tag @mcdil and say that he's been using methods to gather the BC for his bullets rather than just calculated estimates. So it can be done by startup companies. Im glad to hear CE is starting to gather actual BCs for their bullets too.
I feel like this is maybe coming off as a dig on Hammer, and I truly don't mean it to. I'm just making points and using them as an example is all. I sincerely mean no disrespect to anyone or any company.
I've used LabRadar velocity decay data from the first 80-100yds of bullet fight to calculate the BC values of every bullet I shoot in these calibers (.224, .257, .284, .308, and .338). Been doing this ever since shortly after I purchased the LabRadar unit, about 5 years ago.
After reviewing the LabRadar data, and ensuring the pool of velocity decay data is reliable and in close agreement for each bullet fired, this method isn't much more complicated than back calculating a BC value based on long range bullet drops. And the BC values will be more accurate than BCs based on bullet drop, because the human error associated with accurate bullet placement, and the error due to ambient environmental conditions on long range bullet drops, have been removed from the BC determinations.
The equipment required for my method is 1) LabRadar to collect velocity decay data, 2) Kestrel to collect reliable station atm pressure / temperature / humidity, 3) a reliable ballistics program.
The knowledge requirements required for my method include 1) an ability to review, identify, and discard any faulty LabRadar velocity decay data, and 2) competency with the ballistics program.
The extra cost compared to relying solely on bullet drops for BC determination are the LabRadar. And if you're a reloader, and half-serious about long range shooting and hunting, you ought to have a LabRadar anyhow, in my opinion.
One thing I've determined in the past several months is the significant affect barrel twist rate can have on bullet BC value. This became obvious while testing identical bullets from two different rifles. Both rifle chambers were cut with the same chamber reamer. Only significant difference between the rifles are the barrel manufacturer and barrel twist rates. One barrel a 9.4 twist and the other a 8.5 twist. I see a substantial difference in bullet BC value from the two different barrels. The faster twist barrel yielding the higher bullet BC values. I find a much bigger difference in BC value than the ~2% rule of thumb difference Bryan Litz has referenced, from his bullet BC measurements in different twist rate barrels. Dunno if Bryan is still sticking with the 2% figure or not...
A side benefit of my process? If you receive a defective batch of bullets that will not stabilize in flight! I received some defective bullets one year ago that were imprinting 22" groups at 280yds from a rifle that was shooting better than 1/2moa precision with 5 other bullets. The bullets were flying with such poor stability that my BC values were 1/2 the manufacturer's stated BC value. Eventually the manufacturer identified the problem and I received some replacement bullets. I suspect I'd measure similarly reduced BC values from any bullet that was poorly stabilized in flight.
Some bullets I test are very close to the manufacturer's stated BC value. Some values are 6% higher than advertised. Some have been 35-38% lower than advertised. More BC values are calculated lower than advertised, than higher. Some BC values are so low from my barrels that I quickly dismiss use of the bullet for any ranges past ~450yds.
I've learned calculating a BC value with my methods is very repeatable over time. I consider my calculated BC values accurate to within ~ 1.5% from my barrels. As over time, using different batches of LabRadar velocity decay data for the same bullet, from the same rifle, I experience calculated BC values with maximum differences of ~1.5%.
After reviewing the LabRadar data, and ensuring the pool of velocity decay data is reliable and in close agreement for each bullet fired, this method isn't much more complicated than back calculating a BC value based on long range bullet drops. And the BC values will be more accurate than BCs based on bullet drop, because the human error associated with accurate bullet placement, and the error due to ambient environmental conditions on long range bullet drops, have been removed from the BC determinations.
The equipment required for my method is 1) LabRadar to collect velocity decay data, 2) Kestrel to collect reliable station atm pressure / temperature / humidity, 3) a reliable ballistics program.
The knowledge requirements required for my method include 1) an ability to review, identify, and discard any faulty LabRadar velocity decay data, and 2) competency with the ballistics program.
The extra cost compared to relying solely on bullet drops for BC determination are the LabRadar. And if you're a reloader, and half-serious about long range shooting and hunting, you ought to have a LabRadar anyhow, in my opinion.
One thing I've determined in the past several months is the significant affect barrel twist rate can have on bullet BC value. This became obvious while testing identical bullets from two different rifles. Both rifle chambers were cut with the same chamber reamer. Only significant difference between the rifles are the barrel manufacturer and barrel twist rates. One barrel a 9.4 twist and the other a 8.5 twist. I see a substantial difference in bullet BC value from the two different barrels. The faster twist barrel yielding the higher bullet BC values. I find a much bigger difference in BC value than the ~2% rule of thumb difference Bryan Litz has referenced, from his bullet BC measurements in different twist rate barrels. Dunno if Bryan is still sticking with the 2% figure or not...
A side benefit of my process? If you receive a defective batch of bullets that will not stabilize in flight! I received some defective bullets one year ago that were imprinting 22" groups at 280yds from a rifle that was shooting better than 1/2moa precision with 5 other bullets. The bullets were flying with such poor stability that my BC values were 1/2 the manufacturer's stated BC value. Eventually the manufacturer identified the problem and I received some replacement bullets. I suspect I'd measure similarly reduced BC values from any bullet that was poorly stabilized in flight.
Some bullets I test are very close to the manufacturer's stated BC value. Some values are 6% higher than advertised. Some have been 35-38% lower than advertised. More BC values are calculated lower than advertised, than higher. Some BC values are so low from my barrels that I quickly dismiss use of the bullet for any ranges past ~450yds.
I've learned calculating a BC value with my methods is very repeatable over time. I consider my calculated BC values accurate to within ~ 1.5% from my barrels. As over time, using different batches of LabRadar velocity decay data for the same bullet, from the same rifle, I experience calculated BC values with maximum differences of ~1.5%.
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No not at all from my perspective but if you are in a very small startup manufacturing operation, day to day costs are what you keep afloat and to begin prosper. Obviously it would be nice to have at bullet1, but day to day costs for survival are paramount to any manufacturing operation. Time not making bullets or sales may determine if doors stay open. The standard manufacturing phrase still applies: if you are not making product, you are not making money. My point is the cost of the equipment is secondary to having "extra" resources on payroll that is not making product to perform this work. Their time is no longer contributing to their profit. Lathes sitting idle only add to the companies deficit and not profit. Young companies struggle to hit their profit numbers which is why some grow and others fail. Its obviously a shave the beard off Lincoln business to grow and profit or otherwise CE in business since 2001 would have done it as well at day 1. In addition, some of the Hammer BC's are actually stated to be an estimate which should be recognized as "ball park" estimate to help set some basic parameters for finding drops. Companies like CE, BP, Hammer and so on are "boutique" style businesses that are recognized to be used experienced shooters for most part since they do not have reloading data manuals and expect experienced shooters know how to develop loads from their own experience. This same expectation is for BC's IMO. They are provided to get you in ball park set develop your own drops based upon your rifle, load, location, environmental conditions etc.
Lastly, I also asked some follow up questions. Time to perform these tests and or cost to farm out is certainly a mitigating factor in any business decision. Then there is the overall value to the business no matter what the business may be. What will I gain versus cost? Businesses have struggled with this question since first caveman had a fire starting business.
Lastly, I also asked some follow up questions. Time to perform these tests and or cost to farm out is certainly a mitigating factor in any business decision. Then there is the overall value to the business no matter what the business may be. What will I gain versus cost? Businesses have struggled with this question since first caveman had a fire starting business.
I mean, if they can shut the whole shop down for two weeks to go on a costly African safari, surely they can take some time here and there to test some bullets and their BC. And I fully understand the trip is business related and any results they obtain and share can and will be used for testimonials and marketing.
Again, I get your point, but I still believe efforts could be made, and I also think in the long run it would be time well spent for the sake of the consumer/customer.
That's my perspective.
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WiscGunner
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I use s Magnetospeed and have no experience with the Labradar. Could you elaborate on your velocity decay method? Are you just putting 100yrds as you max range in your calculator and adjusting BC value until velocity lines up at 5 or 10yrd increment out to 100?
SnakeRiverEric
Well-Known Member
Let me know what you find out. I shoot all of his bullets.
