Eric Stecker (or anybody else)

Frankly, the effects of lead level in the nose on bullet stability related to yaw, center of gravity and such characteristics is Bryan's realm so I will leave it to him to share his thoughts on the subject.
Click to expand...

You asked for it... :D

I'll offer thoughts from two perspectives:
1. The physical effects of a longer core that's made perfectly (meaning perfectly balanced). This is the 'textbook' answer.

2. The relative potential for dispersion for short vs. long core in light of the inevitable imperfections.

First, the textbook effects...
As Eric stated, a thicker jacket forces the core to be longer. A longer core (all else being equal) results in a lower stability factor for the bullet. Now this is tricky. At first glance, it would seem that the longer core would act to shift the Center of Gravity (CG) forward (which it does). Anyone who's familiar with the mechanics of flight knows that moving the CG forward (in relation to the Center of Pressure (CP)) increases stability. However, bullets are different creatures because they're statically unstable (meaning their CP is ahead of their CG). Bullets overcome their static instability by spinning, which creates gyroscopic stability, which must be strong enough to overcome the static instability. The level of gyroscopic stability that the bullet generates at a given rate of spin is largely dependent on it's mass properties, in particular, the moments of inertia about it's principal axis (spin axis and yaw axis). Making the core longer moves the CG forward which helps stability a little, but more importantly, the longer core increases the moment of inertial about the pitch/yaw axis, and this has a very strong adverse affect on stability. The net effect is a lower stability factor for longer cores. Those interested can refer to the mathematical condition for static stability.
To put this in perspective, I think the cores on the thick jackets are only a few hundredths (~0.020"-0.030") longer than the cores in the thin jackets (Eric please correct me if that's off). This is enough to reduce the stability factor by only a very small amount. Such a small amount that there's no need to recalculate the twist requirements for thick vs thin jackets. We're talking a couple % on something that's got a ~40% safety factor to begin with.
To summarize the 'textbook' considerations; the thicker jackets make for slightly less stable bullets, BUT it's not worth worrying about (don't let me hear about someone ordering a faster twist barrel for their 'thicks' :mad:) A +/- 10 degree change in air temp would have about the same effect on stability as the long vs short core.
It may not be a surprise to some that in this case, consideration of the 'textbook' answer yields no actionable information:rolleyes:, but at least that rock's been turned.

Now for part 2: practical considerations related to dispersion...
The front of the core is a place that's not physically confined, and can sometimes take on an 'irregular' surface, or there may be some lead 'flash' residue from the core seating operation...
Eric touched on this already. When the lead extends farther into the nose, any imbalance at the front of the core has less of an effect on the bullets balance (and dispersion) than if the imperfection were farther from the bullet's spin axis. In other words, think of the top of the lead core as an ugly source of imbalance. The wider the top of that lead core is, the more potential it has to throw off the balance of the bullet and cause trouble. By this logic, longer cores (thick jackets) would stand to lead to more precise bullets.
However...
IF, during the act of forming the bullet with the longer core, it leads to a greater amount of imbalance, then it's a toss-up. The 'good' effect of the narrower ugly area may be offset by the fact that it's twice as ugly. Clear as mud, right?

I don't have any certain answers on this one, but these are some things to think about.

There are certainly examples of inherently precise bullets that have very short cores (like the 155.5 Palma's, thick and thin, being discussed currently) and there are also examples of some inherently precise bullets with long cores (like the 210 VLD).

In summary, I can't think of anything that will certainly give one jacket/core type an advantage over the other (in theory or otherwise). Time will have to tell on this one.

Well, now that I've thoroughly confused things, I'm gonna go out and shoot my long-bow for the last hour before dark :p

Cheers,
-Bryan
 
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Pointing Bullets

Now that Bryan has my head hurting again trying to follow the technical jargon I'll answer Jim:)

Jim,

I very much appreciate your kind offer to point bullets for me and your reasons for feeling the way you do about pointing. I have compared pointed and non pointed bullets at 1k in blind tests and while in every case the drop is less for the pointed bullets and feel that should carry over into less wind drift for pointed ones, I do not feel comfortable shooting them in matches until I do a lot more testing for myself. I did not see more accuracy.

I try; unsuccessfully in most cases, to apply the KISS principle in my shooting. Anything I do to a bullet adds another chance for me to screw it up. One screw up is one too many. I am pretty happy with my selection process and will not be adding another step until I am convinced it will help my scores more than the possibility of occasionally hurting them.

I have used the same load (bullet, powder, primer, brass lots) in my last five barrels. During that time, I too have set a number of national records at various distances. My elevation scores are always near the top of the list in team testing sessions. I may not win every match I enter, but I am usual very near the top. I strive to be as consistent in my shooting as I can be.

Every shooter has his own approach to winning, mine is to beat myself. My rifle, loads, etc are secondary to that goal. You need to understand I only get to shoot matches 3-5 times in a year and test loads about the same number of times. I have only shot one match this year and will most likely not shoot another until I arrive in England prior to the World’s. Until I am able to prove to myself that pointing is the way to go I will stick with what has won a lot of matches of me.

Once again I thank you for your very generous offer, best of luck in your shooting.

To Eric,
Your bullets MIGHT not be perfect, but they are closer than any other brand.
 
Thin v. Thick

Larry:

I understand your point of view perfectly. No need to mess with your recipe for success.

As to Bryan keeping your head spinning, he can do that. But, as you know, he is one of the VERY BEST long range prone shooters in the country. His time will come, and Bryan will win it all at Camp Perry. Additionally, I have no doubt that he will be representing the United States on our Palma team. I feel honored just to have qualified for the tryouts so that I can shoot shoulder to shoulder with the best in the game.

Continued success, but I stand ready to do what I can for you and the U.S. F-Class Team.

Jim
 
I'm not sure this needs to be said, as any one still following this thread probably knows Jim Hardy. I've know him for some time; long enough to forget just how long that's been.

His reply, that started the little fuss accompanying this thread, resulted from his answer to a question I asked. So as to his bona fides -- if needed. All the equipment I've seen Jim shoot and use in preparation for his shooting has been first class. Really first class. He is attentive to detail, much more than me. So when he reports something, I tend to believe it.

Back when Henry Childs was participation on this forum, he got mad at me & Jackie Schmidt (& others) for saying we found a correlation between humidity and the tune-charge of N-133. Henry's point as that none of the models show any causal relationship between humidity and power burn.

The other side of this is no one was using the word *cause.* We had a repeatable phenomena. When a meter reading showed a certain value, a certain thing happened. There may be lots of conditions that apply, maybe it only happened in the Southern States, where it is fairly humid to start with. I don't know, and while t one level I'm curious, at another level -- shooting targets -- I don't care.

Like Jackie, when Jim Hardy reports something, I listen, do my own testing, and usually come to the same conclusion.

The only other thing I'd mention is we've been talking about modifying bullets. Berger, or anybody else, isn't making bullets so we can further modify them. When we do so, we "void the warranty." We know this, no problem. If we get onto something that becomes a proven advantage, and incorporating it doesn't raise the manfacturing costs too much, Berger will, I am sure, make it part of their production bullet. If it raises the costs too high, well, there are only about a thousand (if that) 1,000 yard benchresters in the country. I don't know how many F-class shooters. We're not that big a group, no largish manufacturer can make a living with just us as potential customer.

We understand that, too.

So thanks to Jim for his answers, and thanks to Berger bullets for going as far as they have, and their continued interest & experimentation in accuracy bullets.

Charles Ellertson
 
Hi all , To eric and others at Berger.. While i applaud you guys at trying to make a better product ,the following is mentioned after your request to report any that were substandard..I have in a very small series of tests over the years (since 1997) with 3 different cal bullets of yours found a less than satisfactory outcome in all 3.. That said i also talk to a number of guys in your country that have great results..The second latest lot were 185 Vlds ,they were the worst(only info is a bar code 6 79459 30013 1).By the time they got to me they were actually more expensive than the hand made bullets i normally use ( at AUS$90 per 100).. I have but 77 left out of a 100 ,i fired 4 x 5 shot groups with the same known powder charge(different seating depths) on fully qualified bullets and all were not good enough for my competition purposes ..The way they measure , Base to Ogive high to low (.011), AOL long to short = 1.376 to 1.348(.028) , Bearing surface long to short(.009) = Weight 184.6 to 185.5( .9 gn) and on a small sample (6only) the Juenke devations were 15 to 24..Long story short ,they measured the way they shot.. With the difficulty in being able to actually purchase them here in Australia over the years i was going to just stop trying,but with the help of a friend from the US that has had super results at 1000yd Bench, he sent me 1000 210 vlds(qualifed) . So it's back on the horse i get ..JR..Jeff Rogers..ps please don't read into this anything sinister ,as it isnt
 
Thick v. Thin

Eric:

In finishing up my prep on the 155.5 Thicks for my friend, something caught my eye. So I did a SWAG comparison of the 155.5 Thin and the 155.5 Thick side by side. They "appear" to have been made in a different die for reason that a (my) close examination of the ogive and transition to the meplat on the thicks "looks" like it is different from the thins, i.e., i.e. a slightly different design. Now, I could be wrong -- probably wrong -- it looks close.

But, if I am correct, are any or all of the Thicks being made in different dies than the Thins? Does Berger use multiple dies for the same bullet model, and weight -- like the 155.5 or the 7mm 180 VLD or 6.5 140 VLD -- understanding that it may be commercially desireable not to be limited to one die or machine?

In smallbore, a savy competitor will select Eley ammo from a certain machine and from a certain velocity node -- if any is left over after the big boys test at the factory and take the best. I know that when you place an order for a carbide die from Nemi or others, you expect a great die, but the conventional BR folks who make bullets know that that not all are as great as others. You never know exactly what you are going to get. Bart's will tell you they got lucky with a perfect die. Inquiring minds would like to know how Berger does it.

Is sure would like to see a die/machine indication on each box with a G7 and the Lot #. :)

Forgive all the questions, but it is very interesting stuff to me. I may be asking questions that are confidential and I understand those issues. But many shooters are committed to the Berger product, and would really like to know how Berger does it -- kinda an on-line tour if you will.

Thanks Eric,
Jim
 
Jim,

I'm sure Eric will add to this when he has a chance, but I wanted to see that you get an answer here quickly. If I'm reading your question correctly, no we don't use multiple form dies for the same bullet, certainly not at the same time anyway. Dies wear, and wear out. Carbide dies also occasionally die with a sickening (and expensive) crunch. Obviously, any manufacturer will have extras so that production can be maintained when one goes down. However, when this happens, that's the end of that "lot". The system is cleaned out of the last batch of bullets, and those made after the die is replaced should never come into contact with the previous batch. Despite the best efforts of the machinists and tool & die setters on the press, there will be minute differences between each run, especially when a die is changed, a new batch of material is introduced, an boat tail punch changed, etc.. Bottom line is, when a change is made, a new lot starts. This is the same way that Sierra does it, and Berger is every bit as obsessive about maintaining integrity within a lot, I assure you.

Over the years, I've seen some pretty blatant misinformation put out by folks who should know better. Some years back, a noted bench rest shooter published a book in which he said that large manufacturers (and he cited Sierra as an example) had many different bullet presses running the same bullets, which were then mixed into one big lot. Absolutely, completely and totally false. To begin, it was very rare for more than one, possibly two bullet presses to be running the same bullet at the same time. Even when there were two presses running the same stock #bullet, they were never mixed. We had exactly one customer who required us to mix bullets into "composite" lots before shipment, and even they finally saw the light and stopped doing this many years back. It was easier for their internal bean counters, rather than having to track various lots of components. Fortunately, their ballistics/test guys finally won the argument, and they're producing better ammo today because of that. Anyway, I'm getting a bit off track here, but my point is, nobody who makes quality products allows this sort of casual mixing when changes are made. As we've discussed, there are minor changes from batch to batch, and they're enough to be noticed and measured in many cases. So, the notion of keeping a batch separated by die is something that's already done. trying to identify a "good" die, and only buying bullets from that die isn't really feasible for you, either. As I said, these dies see some extensive use, and they may change over time. Once you have several million bullets off a single carbide die, you can usually measure some minor differences (often still "in spec") but they do change. Believe me, we do our very best to make sure the product stays just as uniform and consistent as is humanly possible. Trust us on this, we'll do our very best to make sure you get the very best bullets we're capable of producing.

Hope you forgive the rambling here, but yeah, you're right; it IS interesting stuff! Been at it for over 20 years now, and it's still a fascinating process to me.:)

Kevin Thomas
Berger Bullets
 
Dies and Bullets

Kevin:

Thanks for the information. I know that when the old 7mm 180 VLD die came to an end some time back, Eric was the first to let us know that it was being replaced. Same thing with the 105 VLDs. That is a stand up way to run a business and gives the shooters a heads up to adjust their seating dies for the new lots off the new dies.

Thanks,
Jim
 
Jim,

A lot more than dies can affect the ogive/OAL/bearing length of a bullet, especially when we're talking about a small variance. I toured the Sierra plan in Missouri in 2005, with Dave Tooley & Steve Shelp. I believe Kevin had left by that time, but what he said was absolutely correct.

Lube, on the other hand, is an entirely different kettle of fish. Sierra believe that it was a difference of lube in the drum with jackets that caused the base to ogive variance the 6.5mm 142-grain bullets are famous for (actually, I haven't bought any 142s in quite a while, maybe they're no longer famous for that). Not sure this was ever confirmed. Nor do I know how Berger does things; it is just one example of how things other than dies can affect bullet production.
 
Bullets

Charles:

You are correct. I used to have long telephone conversations with Ferris regarding making bullets. He always stressed how important the lube was as well as how important it was to maintain a clean environment for the work.

If it were not for the economy, I would roll my own. I would just love to do that -- have wanted to make my own bullets since I was about 14. Maybe that day will come. But until then, I will have to tweek Bergers.

I would love to take a tour of Sierra and Berger -- as well as several of the barrel manufacturers, Kelbly, Stiller, Borden etc. It would inspire me I know.

I just got an e-mail from Joel, and it will be nice to see both of you this shooting season. I will not let another year to by without visiting my old friends at Hawks Ridge. BTW, just like 1000 BR, women and children will just kick your butt in long range prone -- and smallbore. I wish I had started this game long, long ago as I love it so much.

Favor Center,
Jim
 
Jeff,

There was a period of time (roughly 2001 through July 2004) where those in control of the production of Bergers were less than capable. I was not with Berger during this time and even though Walt was involved he was in another state. Those who were running the presses had there own ideas about how to make bullets (which were inconsistent with Walt's methods).

I mention this because of the time frame you list. Berger's reputation took a beating during this time and it was a mess that took a lot of time and effort to clean up. If you (or anyone) has Berger's that do not perform as you expect please contact me directly at eric.stecker@bergerbullets.com. We will make the situation right.

For the last 5 years things are back to normal and much improved. We have partnered with Parabellum to provide a greater flow of bullets to Australians. The current reality is that demand for our bullets has increased tremendously. Lack of supply in Australia is not a result of Parabellum not placing large orders regularly but rather our difficulty in keeping up with these orders. We have expanded our capacity recently and are gaining ground but this can be a slow process as we do not want to lose control of our quality as we make more volume.

Jim,

Kevin spells it out very clearly. We have a given die designated for a given bullet or bullets (based on jacket length). Once it wears out (produces bullets with a .0009 or greater pressure ring) it will be retired and we will start production with a replacement which will be the one die we use until it wears out.

We have a plan in the works to provide discerning shooters with even greater levels of data. I will keep these plans to myself for now as they are in development stages but in time the details you speak of (and other important information) will be readily available.

Regards,
Eric
 
Berger

Eric:

Thanks for the ongoing efforts of Berger to keep improving every aspect of their business and the competitive bullet line. I have come to look forward to new developments from Berger and they keep coming on a regular basis.

Jim Hardy
 
Berger Thicks

Eric
Just to let you know how the thicks actually shoot in competition.Gary Gagliano shot the 105 VLD Thicks to a fourth place in lightgun group at the recent NBRSA 600 Yard Nationals.I myself shot a pair of 49's one day using the thicks as well.Nobody else shot a pair of 49's in one day using any bullet.
Lynn
 
The Thicks

Lynn:

I hear the 108 Thicks shoot real good -- especially in black XTC tube guns in NBRSA 600 Yard BR Nationals with the trigger being pulled by some old prone shooter. :D

Keep up the good shooting. It always seems like you and your Dad have a great time shooting matches together. Dang hard to beat that!

Jim
 
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