338 Bullet Testing / Demonstration LV Nev.

#251
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ELR Researcher</div><div class="ubbcode-body">
Sir:

Possibly you have never tried what I suggested. FYI, I use two comparators, Sinclair's and Davidson's (Davidson's much preferred). I always check to determine if there is any push-back before loading with powder. If the bullet jams in the lands because the bullet was forced back into the case - and you have to unload during a match - there is a significant chance that you are going to dump powder. Possibly you have never shot benchrest. Quite a time consumer to clean out a load of powder if that happens. Only takes 2-3 test cases to check the actual OAL (as chambered) and adjust your seating die. Try it, you may be surprised.

As for the possiblility that Chandalar's last post referred to my recent posts, please reread those recent posts - none on them addressed Stage 1 (the already-concluded tests), only the next round, which appears to be the accuracy round. If you were not referring to my posts, please excuse my comment. </div></div>

So now youre comparing a tactical load for accuracy to a benchrest load, to a Manufacturers load.
IF they do this, yes it would be an accuracy test but i sincerely doubt they will be loaded to BR standards as you seem to suggest doing with your concern of dumping powder due to low neck tension. Concern of dumping powder, really? This test as my understanding is to test stability and overall accuracy of a bullet at "distance". Not a 100,300,600 yard BR competition with minimal neck tension on a round seated to the utmost accuracy node for the bullet.

Maybe I am misunderstanding what your reasoning is for asking for the measurements you are and if so, my apologies. Its just that your requests seem a bit out of line and excessive considering you are not contributing.
 
#252
Re: 338 Bullet Testing / Demonstration LV Nev.

The accuracy test in the spring will more than likely be part of a SH Group Shoot at Gunsite.

To take part in it, I suspect you'll have to sign up and pay as we wrapping it all together but that does open the door for anyone who want to get a little training and shoot ELR Distances at Gunsite. If we get 10 or more shooters I know we are being offered a discounted price on the class.

So, it won't be open in that you can just stroll on Gunsite and shoot, but it will be open in that you can sign up and bring whatever you like to shoot. Cory has a nice program there, with a great range to test your UKD chops at distances over 1000m, out to 2000m.
 
#253
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ply1951guy</div><div class="ubbcode-body">a-hull, every muzzle velocity recorded is listed in the PDF I posted, along with some basic statistics. I posted the link in my second post after the results post, it is there for everyone who wants to see it. Here is is again since you missed it.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ply1951guy</div><div class="ubbcode-body">Thanks for the nice words everyone.

I also put together a PDF with all the information about the fired rounds. It includes the atmospheric conditions for every shot, as well as the recorded muzzle velocity. I do not have any load data, but this shows more of the conditions of the testing.

Muzzle Velocity and Atmospheric Data from Test </div></div> </div></div>


With the tested difference in the berger bullet, could it be the average m.v.'s they had with the berger being a little over 2700 and litz's b.c., is it because he based it on starting at 3000fps? If you could get 2950 to 3000 fps adding 3-5% would get you closer to the stated b.c. wouldn't it?
 
#254
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: a-hull</div><div class="ubbcode-body">

With the tested difference in the berger bullet, could it be the average m.v.'s they had with the berger being a little over 2700 and litz's b.c., is it because he based it on starting at 3000fps? If you could get 2950 to 3000 fps adding 3-5% would get you closer to the stated b.c. wouldn't it? </div></div>

Will they survive? I've been shooting a light load from my Snipetac for 3000fps. Something happens to them beyond 800 because I can no longer see my hits. Now, I must say that I'm using an 1:8"twist and that is likely the culprit. Don't know.
 
#255
Re: 338 Bullet Testing / Demonstration LV Nev.

Hypertex - how old are the berger 300 gr. that you are shooting?

The generation I 300s had problems above 2,850 or so, and were discontinued (at least that is my memory).

If you are shooting the newer release 300s, then I have no suggestions for you.

Jeffvn
 
#256
Re: 338 Bullet Testing / Demonstration LV Nev.

This was going to be asked by someone sooner or later and in no way meant to be antagonistic--when is Bryan Litz going give his very good opinion on his 300gr projectile and these new findings
 
#257
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ch'e</div><div class="ubbcode-body">This was going to be asked by someone sooner or later and in no way meant to be antagonistic--when is Bryan Litz going give his very good opinion on his 300gr projectile and these new findings </div></div>

I'm very interested in his brake down and reasoning as well.
 
#258
Re: 338 Bullet Testing / Demonstration LV Nev.

Cory and I are discussing Phase II now, looking like the last week of March 2012, at Gunsite

We will piggy back on a 3 Day SH Group Course where we can shoot out to distance and then have two days of "range rental" to conduct the tests.

After the holidays we will have more details.


Personally I think the difference comes from the fact where Bryan tested them, if he went out to 600 yards, and we went out to 1200 it just shows a bit more decay than was noticed at 600.

When calibrating ballistic computers you want to get as much hard data, like actually doping the rifle out to distance and working that data into the model for the B Calculator to work with. Like getting the drop at 800 yards around 1300fps as opposed to 300 yards. So here by taking it out further the decay is showing to not be linear.

it would seem to me, logically, that if you shoot the 300gr or any other bullet with a manufacturer BC inside 1000 yards you can use the published number, but if you go beyond 1000 yards the new number would be more valid because it is showing the decay there.

Because the guys at KNS talked to Bryan and there is no "glaring" error, or problem in their process, which I think if Bryan recognized one and relayed to the guys they would have said something, I would venture that the difference is distance / velocity issue where the decay changes. I'm not a math or science guy but I still wouldn't be scratching my head over it, I would simply believe the bullet.

Once everything is shot at distance on a target for drop and accuracy the numbers will flush themselves out even more. Either they will prove to be closer to right based on Phase 1 or closer to wrong based on the Manufacturer.
 
#260
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rocky Mountain</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ch'e</div><div class="ubbcode-body">This was going to be asked by someone sooner or later and in no way meant to be antagonistic--when is Bryan Litz going give his very good opinion on his 300gr projectile and these new findings </div></div>

I'm very interested in his brake down and reasoning as well. </div></div>

We (KnS and I) discussed the difference between our results at length when their assessments were published. To summarize, we are very eager to pursuit joint testing in order to learn what we can from each other in order to provide consistent and repeatable test results. When this joint testing comes about, I'm sure we'll address this forum with our findings.

In the mean time, I can share more information regarding my test results with the .338's.

As some of you may remember, when this bullet (the .338 cal 300 grain hybrid) was first released (Gen 1), I had assessed inaccurate performance (.455/.889, G7/G1) based on testing at 600 yards. Further testing at 1000 yards indicated the currently assessed performance of .418/.819, G7/G7.
The cause for the discrepancy in my results is not attributed to BC decay at 1000 yards vs 600 yards, but rather testing at 600 yards is simply too error prone to work with larger caliber, high BC bullets. In other words, normal uncertainties in MV, range, atmospheric variables etc result in unacceptable % uncertainties in measured BC. When measuring the BC of a high BC bullet, the test has to be conducted at longer range in order to manage the measurement uncertainty.
Due to the initial discrepancy of my own results, I proceeded to conduct extensive testing on this bullet at 1000 yards to be 'sure' it was right. The following are my test results by date for this bullet:
date: barrel, performance (G1/G7)
6/1/2010: 1:10-9" gain 30" Bartlein, .819/.420
6/5/2010: 1:10-9" gain 30" Bartlein, .811/.415
6/5/2010: 1:10" 28" Krieger, .825/.422
6/5/2010: 1:10" 28" Krieger, .825/.422
7/7/2010: 1:10" 27" Sako (TRG-42) .822/.421
2/15/2011: 1:10" 27" Sako (TRG-42) .809/.414 *note; low confidence test due to poor light conditions and suspect chrono #'s
2/24/2011: 1:10" 27" Sako (TRG-42) .817/.418

During the 6/1/2010 test, the bullets were also shot for 'drop' at 1000 yards which resulted in BC's of .824/.413. These results are considered lower confidence than the rest of the (tof based) results due to the uncertainties related to drop testing for BC. Nevertheless, the numbers line up well with those derived from tof.

The compiled results make up my (Berger's) assessed performance of:
G1 BC = .818, and G7 BC = .419

I don't think the difference in our results (KnS and mine) are related to BC decay between 1000 and 1200 yards. It's true that G1 BC's vary widely with Mach number, but the G7's wouldn't be 7% different based on just 200 additional yards of flight. There's something else about the tests that are producing different results. It's curious that we measured the same BC for the SMK (the first bullet they tested) and the % error between our results steadily grew thruout the day in the same direction from 0%, to +2%, to +4%, to +7%. Their measured BC for the SMK was only 2% lower than the Berger Hybrid. Just looking at those two bullets side by side reveals dramatic differences in shape which ought to add up to more than 2% difference.

Based on the extensive and consistent test history I have for this Berger bullet and the feedback I've gotten from ELR shooters in the field, I'm confident in my current performance assessment for this bullet. However I'm still very eager to get together with KnS to see if their result is repeatable, and if so, why it's different from mine. It's not about ego or being 'right' for the sake of argument; rather it's about learning how to conduct consistent, reliable, repeatable, and meaningful ballistic performance assessments so that other shooters can make well informed decisions about their hard-earned money.

There are other interesting trends in the KnS test results besides the minor difference in measured BC compared to my results.
1) The difference between manufacturer advertised and measured BC for all the conventional (jacketed) bullets is less than 10%. However, the difference between advertised and measured for the solids is 19% in the case of the GS bullet, and 47% for the Predator (http://www.southwestammunition.com/category_s/96.htm). I couldn't find advertised BC's for the ZA276 or the 245 Lehigh. This dramatic discrepancy of claimed performance for monolithics is documented in chapter 18 of my second edition. This is not to say that monolithics are bad, but simply that it's difficult to estimate what the performance will be due to the radical nature of the designs. Factors such as driving bands and additional skin friction drag (from longer lengths) are a couple reasons why it's hard to nail down what the drag will be. But even with the actual performance known, they can be very good, accurate, reliable, consistent bullets capable of reaching out effectively to very distant targets. Just be careful to be realistic about the performance.
2) Although the Berger 300 grain Hybrid has the highest BC of all the bullets tested, that doesn't mean it's necessarily the best overall choice due to the lower MV it's capable of. I figured most of this crowd understand that, but wanted to point it out for clarity.
3) KnS test identified the 245 grain Lehigh as being the actual 'lowest drag' projectile in the test, having a G7 form factor of .92. This is a bullet I've not tested so I can't comment on that result from a verification POV, but I can say that my performance assessment of the 300 grain Berger is a G7 form factor of .90 (a little better than what they measured for the Lehigh).

As you can see, you can make several conclusions about trends that are universally supported by both my and KnS' work. Some conclusions are somewhat supported by both, and some conclusions are simply contradictory. So the tests were a success in the sense that they shine some more light, and when we get a chance to sort out our testing methods together, hopefully we'll get that light focused and revealing the same answers.

Happy Holidays,
-Bryan
 
#261
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jeffvn</div><div class="ubbcode-body">Hypertex - how old are the berger 300 gr. that you are shooting?

The generation I 300s had problems above 2,850 or so, and were discontinued (at least that is my memory).

If you are shooting the newer release 300s, then I have no suggestions for you.

Jeffvn </div></div>

I've tried both. Next barrel will be 1:10 I think.
 
#262
Re: 338 Bullet Testing / Demonstration LV Nev.

"Factors such as driving bands and additional skin friction drag (from longer lengths) are a couple reasons why it's hard to nail down what the drag will be."...

We actually do know a bit more than this.

While arifoils, and fuselages, do not sport engraving bands, there are decades of data supporting the conclusion that skin drag is never a significant consideration in off-setting the reduced wave drag effects which accrue to a high aspect ratio... at least not in any length for which spin-stabilization on a body of rotation, as in a bullet, is practical option.

There are, however, at least two sources now at both ends of the caliber scale that attribute considerable drag to the poly-band configuration. The path forward seems fairly obvious.

What is groundbreaking about the SH sponsored test is that this information will be collected, and disseminated, very rapidly through the industry in a coherent form.

The beneficiary is the consumer, because knowledge drives change.
 
#263
Re: 338 Bullet Testing / Demonstration LV Nev.

Bryan,
Thanks for the update. Looking forward to the joint testing results. Should be quite interesting.

Bryan Litz said:
"Factors such as driving bands and additional skin friction drag (from longer lengths) are a couple reasons why it's hard to nail down what the drag will be."...[end quote]

[quote Noel] We actually do know a bit more than this.[end quote]
<span style="font-weight: bold">If that is so, Noel, then how do you explain your predicted (pre test) B.C. for your bullet? </span>

"There are, however, at least two sources now at both ends of the caliber scale that attribute considerable drag to the poly-band configuration. The path forward seems fairly obvious."

Noel, Care to explain this in more detail? Sounds High Tech.
Click to expand...
 
#264
Re: 338 Bullet Testing / Demonstration LV Nev.

Wadcutter,

You willl search in vain for a "predicted" BC from ZA. What you will find are some field calculated BCs provided by beta testers... that are not really much further off than the Gen I Berger estimate. Errors are ubiquitous in this realm of manufacturer research, which is why the contribution of KnS is so valuable.

My first source of inferential data is the morphology of Krupp artillery shells. This was quantified later by an English ballistician during WWII, who was interested in increasing the effective altitude of AAA batteries, by the name of Probert.

It is our resident PhD, Francis, that got me looking at band drag on small calibers over a year ago. I believe this test is a validation of his numbers, and I will be holding my own confirmation test very soon.

What you can be certain of, at this point, is that "skin drag" associated with long ogive designs is *not* the source of unanticipated low BC values.
 
#266
Re: 338 Bullet Testing / Demonstration LV Nev.

This is really interesting data but I have a couple of questions:

1. If I read these many pages correctly, it appears that even very good, long in business, bullet makers cannot be trusted to provide accurate data on their bullets. (Berger, Sierra)

2. While all the info on BC etc is very valuable, the "beef" is: how do they group ?
+200 fps @ 2000 yards for bullet A over bullet B doesn't mean much if the groups are three times as large.

While my long range shooting has been limited to 1000 yards, I have found that slower is sometimes more accurate.

When can we see groups ? Thanks.
 
#267
Re: 338 Bullet Testing / Demonstration LV Nev.

BC's from the mfg are usually done over two chronos at 200 to 300 yards in an indoor range. These were averages over 1200 yards, so that's some of the differance right there. We are setting long range test dates for groups right now, looking like the end of March.

To a certain degree, you are correct, velocity is not the only issue. However, more downrange velocity is better, all other things being equal. This is only the start of the process.
 
#268
Re: 338 Bullet Testing / Demonstration LV Nev.

I'm aware I'm late to the party here. If you are not completed with all your BC testing, would any of you have interest in shooting some 325gr Rocky mountain 338s as well as some 300gr cutting edge 338s? I would sponsor the bullets obviously.
 
#269
Re: 338 Bullet Testing / Demonstration LV Nev.

Jmason,

We have the Lapua, and most current ZA, to run over the chronographs still,

There is no reason that we cannot include Rocky Mountain, and Cutting Edge.

PM me.
 
#270
Re: 338 Bullet Testing / Demonstration LV Nev.

Jeff, and I, ran a comparative test of the old ZA338/6.5 against the new version that had not been validated for long range stability in time for the chronographs.

At 1,775 yards the new iteration is striking the target .50 to .75 minutes higher with mass, and muzzle velocity, being held constant between the two versions. The bearing foot-print was shortened slightly along with a correspondingly increased length value used in generating a new Von Karman ogive... but I believe that the increased performance can be attributed to a single modification; one of the five bands was eliminated.

We are working with two rifling geometries that will remove 75%, and 95%, of the engraving band drag respectively. If yesterday's test is a reliable indicator, then it is possible that a net gain of up to 3.6 MOA in trajectory at 1+ miles is obtainable through a better form factor alone. This will not be ready in time for the March accuracy test, but a weight increase to 300 grains will be part of both the 6.5 caliber match bullet, and the standard twist hunt bullet.

Perhaps the mini controversy stirred up of late over the chronograph data can be addressed through a repeat BC test scheduled to precede the accuracy test (?). I would like to corroborate the band drag estimate, and jmason has generously offered to supply bullets from Cutting Edge, and Rocky Mountain, to supplement the test pool.
 
#271
Re: 338 Bullet Testing / Demonstration LV Nev.

With the results shown so far being different to what has been published does this mean Applied Ballistics book is giving incorrect data for all projectiles Bryan has tested due to him testing at the shorter ranges ?I use the Berger 180gr target VLD projo and the .337 g7bc seems to be pretty good ,is it just that am I willing it to hit bulls eyes that it does so ??
 
#272
Re: 338 Bullet Testing / Demonstration LV Nev.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ch'e</div><div class="ubbcode-body">With the results shown so far being different to what has been published does this mean Applied Ballistics book is giving incorrect data for all projectiles Bryan has tested due to him testing at the shorter ranges ?I use the Berger 180gr target VLD projo and the .337 g7bc seems to be pretty good ,is it just that am I willing it to hit bulls eyes that it does so ?? </div></div>

That would be a big jump to make such an assertion.

Since 2009 there have been a lot of shooters reporting excellent results with Mr. Litz's published BC's. The latest test is only 1 bullet from the hundreds that he tested and published, hardly enough to make any sort of assertion or accusation against his published bodies of work.

As I mentioned before, the KnS Ballistics team and the Applied Ballistics team spoke at length regarding both testing methodologies, both setups and their potential sources of error and there was not an "a-hah!" moment where any of us said "That's the problem" definitively.

Again, the assertion that we should be invalidating the work that Mr. Litz has done to date is what the TV industry would term "jumping a shark".
 
#273
Re: 338 Bullet Testing / Demonstration LV Nev.

As mentioned I use Bryan's data to 1000 yards accuratly and I am sure he is consistant in his testing.If results are different between people I am sure it not because someone has found out suddenly how to make the equations 1+1 =3 , someone got it right and some else will need to make adjustments
It is good for all formulas and methods to be tested and proved -the future for these tests will continue to be very exciting for us all ,thanks!
 
#275
Re: 338 Bullet Testing / Demonstration LV Nev.

I would like to thank all involved in this project...looking forward to any and all futrue data...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jeffvn</div><div class="ubbcode-body">Hypertex - how old are the berger 300 gr. that you are shooting?

The generation I 300s had problems above 2,850 or so, and were discontinued (at least that is my memory).

If you are shooting the newer release 300s, then I have no suggestions for you.

Jeffvn </div></div>

Man what have I missed on the 300s,I am curious as to when the new release took place as I have been away from shooting for a few years and have a hopefully usefull stock pile of bullets to use ...
Any info or link would be awesome thanks

God Bless America ..
 
#276
Re: 338 Bullet Testing / Demonstration LV Nev.

the nice thing is, thanks to a member of the Hide we now have 2 boxes of GSC Bullets 338295SP142 so we can do an actually load work up and accuracy testing, and will put this to rest on our own.

They continue to shift and dodge with their information and position on the matter, so we will simply move forward on our own with "purchased' bullets.

Our sampling of bullets continues to grow.

if anyone wants to be present at the next phase we will be at Gunsite the last week of March and it is open to anyone who wants to attend.
 
#278
Re: 338 Bullet Testing / Demonstration LV Nev.

According to the box I have, they recommended twist rate is 1-7, which I don't know who uses a 1-7 twist 338LM... so it may have to use a 1-9.5 AWM because I highly doubt and I don't see the point of making a dedicated barrel for this when we have very good rifles with 1-9 twist rates we are using.

So 338LM out of an Accuracy International AWM

edit: I have a gain twist coming and I was told if the barrel is cut to 24" it will be a 6.75 exit twist. So there is always that possibility.
 
#281
Re: 338 Bullet Testing / Demonstration LV Nev.

Odds are I won't especially with GSC being as combative as they are. And with the bullet asking for a 7 twist it seems silly.

With all the support we are getting from other manufacturers it seems foolish to give them any attention so after this I suspect we'll just let them fall off the radar and bring attention to those willing to work with us in stead of against us. When you consider the cost, I would recommend people support companies that embrace the end user, and not constantly change things, then argue against products they sold.

There is a considerable expense to this, so if we can help people wade through the nonsense it only makes sense to let the market decide.

Moving forward it will be out of sight out of mind. Too many choices to play games.
 
#282
Re: 338 Bullet Testing / Demonstration LV Nev.

It is good to see some straight data. I was not surprised to see that solids with bands did not do as well as hoped. As one earlier poster stated bands can be called "drag bands." Any gain in muzzle velocity will be lost to drag. With the right platform anyone can shoot a bowling ball with a muzzle velocity of 3100 fps. However, the drag will be terrible downrange. A 220 Swift is smoking at 4000fps but the extended range performance will be terrible. This series of tests was solely on BC and as all readers here know BC is very important. I have shot many solids made on a CNC to my design and I have shot solids that another person produced for sale. Some solids can shoot very well. However, it is difficult to improve upon a quality jacketed bullet. Jacketed bullets in my experience are always less expensive and quality jacketed bullets shoot world class. In addition, in my experience solids were harder on barrels and foul more. I made rifle barrels for a living and I probably made around two dozen fifties. That was long before ELR became so popular. There have been many efforts to improve upon spin stabilized projectiles. Sierra and Bergers (and similar forms) are about as good as we are going to get. There is not much room for progress in bullets. I have been very suspicious when I read/hear about wonderous improvements in a bullet. Gains in BC are hard to make in the real world. I am very confident that putting bands on small arm projectiles is going the wrong way if you want high BC. Again, it was good to see data. Talking is great but testing is better.
 
#283
Re: 338 Bullet Testing / Demonstration LV Nev.

Jerry,

It is difficult to make significant improvements on well executed jacket/lead designs. I also agree with nearly all of your criticisms of monolithic solids, and your background as a barrel maker will give you a perspective that most people lack in this discussion.

Consider two variables that are assumed to be constant:

- Tungsten has a much higher specific gravity than lead, and works well as core material on banded solids.

- There are rifling geometries that do a wonderful job of burnishing engraving bands flush with the shaft diameter.

How do these two factors effect your estimation of the potential of turned projectiles?

In the very near future the hard numbers will be published on this forum.
 
#284
Re: 338 Bullet Testing / Demonstration LV Nev.

Noel
I know that you are well aware of the challenges of making high quality bullets. As for any specific bullet design the best one can do is model the bullet and project how it will perform. Testing is the only method to determine how well the bullet does in the real world. If one goes with some type of composite projectile it gets harder to hold tight manufacturing tolerances and keep costs down. Bullets with higher specific gavity are usually heavier and then suffer on the velocity side.
I am in no position to comment on the performance of your designs. I applaud anyones efforts to make a better bullet. I know how hard it is to make a new product. I know what it feels like to have high hopes that just do not pan out. In those cases it is back to the drawing board. The only thing that stands between our ideas and actual performance is scientific testing to the best of our means. It is expensive to run tests and they take a lot of time. I cannot speak too highly of those parties who ran these tests. When one runs tests it is impossible to please everyone. There are always critics of the data and the method. There are always more questions than answers. In all cases it is best to let the data stand alone and clearly explain how the data was collected. Often data is collected that is mystifying in some particular. All that honest people can do is test again if possible. Scientific proof is hard to get but I feel the truth is worth the effort. It must be kept in mind that BC is only one factor in bullet performance. These tests only addressed BC and that was made clear. Cost will always be a serious hurdle for product acceptance. The more complex the bullet design the harder it will be to make it and harder it will be for the shooter to afford to buy it. In these tests performance the only thing tested with no regard to cost. That makes perfect sense. What is the best we can get at any cost is a great motivator.
I am completely open minded about projectiles with banding. So far, my life experience (only one mortal) has shown that bands will degrade BC. If tests show that I am wrong then I will clearly admit my error and congratulate the designer publicly. Again, I do not feel qualified to judge any bullet that I have not tested. I hope I have answered your questions.
 
#285
Re: 338 Bullet Testing / Demonstration LV Nev.

Jerry,

Engraving bands *do* contribute to drag, material density does factor into BC, and component construction adds to cost.

We agree upon this.

I am also one of the first to be critical of sloppy test protocol, and cooked evaluation reports.

If these issues are effectively addressed, does that alter your estimation of engraving band designs per se?
 
#286
Re: 338 Bullet Testing / Demonstration LV Nev.

Noel
If any banded projectile design shows a higher BC than a comparable weight jacketed bullet in head to head tests then I would certainly acknowledge a superior design. I hoped I had made that clear in my last post. I have seen no evidence at this point to give banded projectiles any extended range advantage whatsoever.
If you believe as I do that bands increase drag, that material density influences BC and that costs are typically higher in solid projectiles then I can't see where we are far apart. You have also implied that you agree with good protocol and good test evaluation. It should follow that the burden of proving banded bullet superiority rests with you or other designers of such products. If jacketed bullets outperform solid designs and are cheaper it will be difficult for the shooter to justify solids.
I have no ax to grind at all. Unfortunately, proving that banded solids are superior to jacketed bullets has not been successful to date in small arms. Ultimately opinions don't matter if actual testing is possible. Many a race horse owner has felt they owned the fastest horse. However, it is the performance on the track head to head that settles the issue. I hope that your product meets your expectations but I have to remain sceptical until the evidence convinces me to shift.
 
#287
Re: 338 Bullet Testing / Demonstration LV Nev.

We are very close on all points but one.

A fair interpretation of this set of test results demonstrates that solids of "equal weight" outperform jacketed equivalents... at least the three year old ZA design that was substituted for safety reasons.

My preferred design was not represented in this round.

Turned projectiles will always cost considerably more than a jacketed bullet, but they will be within reach of the type of shooter that plays the performance game.
 
#288
Re: 338 Bullet Testing / Demonstration LV Nev.

Very interesting test and results! where can I find an homepage for these ZA bullets? I have been looking all over the internet without finding them.

Im a beginner bulletdesigner who are working on some CNC machined bullets. To me it seems like the ZA bullet must have a much better formfactor than the Berger to achieve such a high BC when it is so much lighter. But that might be because its designed for a faster twist which it was shot from. The berger is designed for a 1/10 twist and if this bullet is designed to be stabile in 1/9,5 it can probably outperform the Berger even though it is made from a lower density material.

Do you have any estimates of what initial stabilityfactor the ZA bullet had at range?
smile.gif
 
#289
Re: 338 Bullet Testing / Demonstration LV Nev.

Hello Scratch,

Bringing these to market has been a five year project.

It involves not only the projectile, but barrels, and cases... all through the collaborative efforts of associates who possess specialized skills unique to their area of expertise.

Finalization of licensing agreements which will ensure wide, and reliable distribution, along with the structure to enforce patent protections, are near completion... at which point you will have no difficulty finding, and purchasing ZA products.

Noel
 
#290
Re: 338 Bullet Testing / Demonstration LV Nev.

Hello Noel! Thanks for your reply
smile.gif


I found some pictures of your bullets and they look very interesting and similar to lutz mueller designs, which is one of the bullet designers I really admire. Is your work a colaboration with him?

I must say that I am eager to see you set up shop, will be promising for sure.

kind regards
/Scratch
 
#291
Re: 338 Bullet Testing / Demonstration LV Nev.

Scratch,

My early designs were very similar to Lutz's, and there was a period during which we collaborated on rifling forms that would best utilize the engraving-band concept. We parted ways back in 2008.

From the standpoint of product development, this was fortuitous... as the ZA projectile has benefited from improvements accrued through *actual* testing.
 
#292
Re: 338 Bullet Testing / Demonstration LV Nev.

<span style="font-weight: bold">Noel</span>
I will buy your bullets when they arrive. Bullet designs are so interesting. and I applaued everyone who comes with forward thinking
smile.gif

If you could teach me how to estimate gyroscopic stability for a given twist when the bullet has a von Karman/sears haack ogive I would easily sacrifice my left nut, I am having serious problems figuring this out since the form doesnt have a Rt/R ratio which means I can really use mcGyro to estimate it
laugh.gif


I did som quick math over the bullet testet and to me it seems that the bullet that has the lowest formfactor is the Leheigh 245 grainer which formfactor I estimated to around 0,92, The CZ is secondplace at a formfactor of 0,94 and the Berger is third at 0,95. But I am not prepared to take poison on this today since I am quite hungover, someone might have to double check this statement;)
 
#293
Re: 338 Bullet Testing / Demonstration LV Nev.

Scratch,

The relative G1 form factors of the Berger, and ZA were posted earlier. I did not calculate the Lehigh because it is too small to hold the requsite mass.

You are spot-on about the stabilization problem... I solved it.
 
#294
Re: 338 Bullet Testing / Demonstration LV Nev.

<span style="font-weight: bold">Noel</span>
I did my estimates in relation to the G7 drag curve. But my calculations might be wrong, I havent double checked them. but if its true its interesting that Leheighs use of "inverted drive bands" gets a lower form factor than the ZA. But the test doesnt tell what SF the bullets had when fired so I cant really determine if that is the way to go or not. If the leheigh bullet had a higher Stability factor than the ZA bullet when fired, then that bullet in my mind is more optimal.

As to gyroscopic stability I can only do a a rough estimate of it by comparing the form to a secant and tangent ogive of the same length. I can only guess about this but to me the von karman seems to be less stable than a tangent ogive when the ogive length is realatively short, but they all pan out to be quite similar when the ogive lengths are long.

I understand that you dont want to give all your trade secrets away. Just consider me a curious spectator
wink.gif

 
#295
Re: 338 Bullet Testing / Demonstration LV Nev.

Scratch,

Of the four options:

- Secant Radius Ogive
- Tangent Radius Ogive
- Haack L-V
- Haack L-D (Von Karman)

In order of stability for a given length:

- Haack L-V
- Tangent Radius Ogive
- Secant Radius Ogive (conditional, may switch with Von Karman)
- Haack L-D

In order of increasing drag for a given length:

- Haack L-D
- Secant Radius Ogive
- Haack L-V
- Tangent Radius Ogive

There is no secret about this. The challenge is to take the optimal form for a given length (Von Karman), and stabilize it at a maximum mass, dictated by internal ballistics, in order to obtain the highest possible BC.

Another approach is to design to a specific maximum range, in which the time of flight is minimized, but the Von Karman is still the optimal nose form of choice... the projectile is simply reduced in weight.
 
#296
Re: 338 Bullet Testing / Demonstration LV Nev.

hehe I dont want to argue with you, since I dont know half what I am doing. I use Robert McCoys formula for stability, and it says that secant ogives are more stable than Tangent ogives. Maybe i have programmed it wrong somehow but I dont think so. in the beginning I used Don Millers formula for stability and with that you will get a higher stability for tangent ogives than secant since it uses mass as a factor and not shape. I have tried different setups in loadbase as well and that program tells me the same thing.
i agree that the sears-haack shape is one of the lowest drag shapes in certain mach speeds but my conclusion is that its not the most optimal shape from a gyroscopic stand point.
However I dont have a PhD in physics so I might misinterpreted McCoys work. i am just a computer geek who likes to program stuff when I am not shooting.

Kind regards!
/Scratch
smile.gif
 
#297
Re: 338 Bullet Testing / Demonstration LV Nev.

Scratch,

The Mach number does have alot to do with both the drag, and stability of the nose type... I am making a generalization specific to our area of interest.

The Haack L-V works best between Mach 2-3 when holding length constant. The Von Karman comes into its own below Mach 2 under the same constraint. No shape is optimal at all velocities, but the Haack L-D is a very good compromise for the velocity envelope of rifled guns. It is also the most difficult to spin stabilize for precisely the reasons that you have alluded to... mass distribution, and magnus effect. The stability formulas are worse than useless once a projectile exceeds six calibers.

That is why tungsten is such a critical component of extreme range performance. It is also why the Lehigh is marginal on BC regardless of distribution... it simply lacks the potential for adequate mass.
 
#298
Re: 338 Bullet Testing / Demonstration LV Nev.

Noel

Hi again. I was a little bit confused earlier because I had not experimented with Hack-LV or Hack-LD "ogives. My only tests has been run on the sears-haack shape, which I kinda have discarded because of stability concerns. The Hack-LV and hack-LD looks more promising even though the LV to me seems to be almost exactly like a 0,5 Rt/r secant ogive. calculating stability for these shapes are very hard for me since they are not constructed around a radius, but I think I have managed to achieve a fair estimate after consulting with some physisists.
I cant however make those shapes perform better than secant or tangent ogives in my computer program. Even though they seem to perform in parity, But I will make sure to test them out and see for myself, maybe the reality is much better than what my computer program says it is.
wink.gif
 
#299
Re: 338 Bullet Testing / Demonstration LV Nev.

Scratch,

When the Sears-Haack is referenced, it is usually the Haack L-V that is being discussed. You have me wondering what nose type you were actually testing.

Both of the Haack formulas generate a secant nose configuration, but it is easy to distinguish these from *any* radius ogive.

Unless you are extremely talented at CFD analysis, and programming, your best option is to control for CG, mass, and length in performing field trials of your own. Use the classic 1/2/3 tail(7 degree)-shaft-nose ratio measured in calibers, and get yourself an 18-caliber twist proof barrel.

Ask me in a pm how to maintain a constant CG, and total mass.

Best,
Noel
 
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