Ogive Variation?

[Joe Salt]

Joel yes your doing fine were not trying to tear each other apart or anything, its just the way it looks on here when we type something instead of talking it out, can't tell who is mad or not. Just hard to get your point across the right way. And yes that is another thing I do is put my bullets through a bushing, to make sure there not to fat.

Joe Salt

 

[Boyd Allen]

Nader,
Nice information. Now... You have explained to us how base to ogive variations happen, even though the same point die is used. Three questions....first, if cores are run through a squirt die before they are seated, would there be greater base to ogive uniformity? Second question, since the relationship of the ogive to the leade (in chambered ammunition)is what we are trying to keep uniform, and the seating stem is the point of contact for seating the bullet, doesn't if make sense to look at bullet to bullet variations in the distance between where the stem would hit the ogive, and that part of the ogive where the rifling will make first contact? Third question have you looked at this dimension? Again, thanks for the information.
Boyd

 

[Greg Culpepper]

And you will get less variation measuring base to ogive than ogive to ogive. that is why people are see the difference in there seating.

Joe,

I'm not getting it. Help me here.
Are you saying that seating depth measured to bearing surface will be more consistent by sorting bullets by base to ogive as contrasted to sorting for bearing surface length? Naw, that's not what you're saying. Tell me again, I want to understand this.

Greg

 

[Greg Culpepper]

Joel yes your doing fine were not trying to tear each other apart or anything, its just the way it looks on here when we type something instead of talking it out, can't tell who is mad or not. Just hard to get your point across the right way. And yes that is another thing I do is put my bullets through a bushing, to make sure there not to fat.

Joe Salt

Joe,

Does a neck bushing work for this or are you using something else? What results are you finding in percentage of culls?

Greg

 

[Nader]

Nader,
Nice information. Now... You have explained to us how base to ogive variations happen, even though the same point die is used. Three questions....first, if cores are run through a squirt die before they are seated, would there be greater base to ogive uniformity? Second question, since the relationship of the ogive to the leade (in chambered ammunition)is what we are trying to keep uniform, and the seating stem is the point of contact for seating the bullet, doesn't if make sense to look at bullet to bullet variations in the distance between where the stem would hit the ogive, and that part of the ogive where the rifling will make first contact? Third question have you looked at this dimension? Again, thanks for the information.
Boyd

Boyd,
Certainly the goal when squirting cores is to have absolute uniformity but this procedure is far from perfect. The core cutting from lead wire is a rather brutal affair and the lead wire itself is not precision extruded from the lead supplier,so the rough slugs vary quite a bit,naturally one has to squirt off the excess and that is a human controlled and cadenced stroke,so a little variation there. The jackets are pretty good as far as I can tell without any fancy interior mics( my tubing mic only gets about halfway in) I would imagine, like brass cases there are volume variations caused by differences in the tapered wall thickness. So on the core seater, if a slightly heavy ( or light core gets pared up with a slightly heavy ( or light jacket) then you are gonna seat a core under heavier or( lighter) pressure than the preceeding ones. If you dont catch it by feel and cull it you'll end up with a heavier( or lighter) CSJ,and thus a longer (or shorter) ogive reading than the other bullets once it goes through the point die.
The point I was trying to make with the seater stem contacting the bullet way up the ogive was that the ogive on the heavier/fatter bullet is swelled where the ogive meets the rifling(I think the harder to displace lead in that area is the culprit,(harder to displace than a plain jacket wall and a little air up in the bullet nose).So the ogive is changed but the nose where the seater stem contacts it is unaffected. So your seater is pushing the bullet nose down to the same place but the expanded shoulder/ogive of the rogue bullet could be in a different spot than it is with all the others.
As far as measuring the spot between the seating stem contact and the ogive where it meets the rifling,I don't know how that would be accomplished with a standard .0001 mic ( that "me not being a scientist" thing keeps creeping up).
Joel

 

[Pete Wass]

Amen

Boyd and others,
I am kind of reluctant to jump in here because I am not in any sort of authoritive position.,nor do I understand the science end of things,nor do I wish to have the "flesh ripped from my bones" by the current flock of non-appreciative BR Central buzzards that have nothing to offer but criticism.
However, in my bullet making infancy,some things have come to light that I never understood before when I was just a shooter( and barely understand now).Anyway, here are my observations for the moment:
Seating stems push on the bullet from a place well above where the ogive contacts the rifling. I have a gizmo(chamber gauge stub that mounts on my "el cheapo"calipers) that pretty accurately measures base of bullet or base of loaded cartridge to the portion of the ogive that actually contacts the rifling in my chamber.. I can also measure a .825 long jacket on a standard caliper, Doing this on 100 jackets, an .825 jacket is boringly .825 long( yeah,J4 !)Now lets core seat some jackets,One with a 65 gr combined weight and one with a 68gr( different punch diameters and die settings of course),the jackets change length a little but remain consistant. Now over to the point up die we go.Same setting, same jacket different weights.The bullets come out of the point up die with the same overall length but with two different ogive readings. The heavier bullet with the longer ogive reading. OK, so take three .825 jackets and three identical weight/volume slugs,and adjust the core seater die up and down a smidge(a freekin smidge)and run these three same weight/length CSJ's in the point die and guess what? three different base to ogive measurements that correspond to heavier (longer)CS pressure or lighter( shorter) CS pressure. OK, so with the most stringent human efforts possible,one is still gonna get a slightly heavier/lighter core jacket combo come down the line and that is where the bullet makers "feel" is gonna notice the difference in CSpressure and hit the brakes and throw that bullet into the "cull pile". Doing that, all of the bullets in that run will have the same base to ogive measurements. Don't do that, or let Sierras machine completely ignore any variances and you will get different base to ogive measurements in your box of bullets.
Now how does this apply to paper? If you tune your rifle on a razors edge and it will only shoot one seating depth and one powder charge and then you throw some not really shure about consistancy bullets in it, your "tune " is going to be easily compromised. If you tune your rifle with a broader seating depth window, then the broader tune will suck up the variation. That is why hard to tune high ogive and VLD's frequently respond to jump tunes. The jump space sucks up the variation ( it should be obvious by now that I'm no scientist)easy to tune low ogive bullets that will shoot from .005 off jam to .015 off jam and do it with three diffrent "numbers" of powder will also suck up the variation.
bullet diameter must also be held consistant to get best performance( in the critical core seating pressure adjustments) So you see, there is a lot more to bullet consistancy and rifle tune than previously meets the eye.
Joel

Exactly what I have observed for years.

 

[Pete Wass]

Variations:

There is one little point that I would like to make, and it is not who should be where. As far as I know, there is only one gauge that will show differences in distance from where a seating stem would touch a bullet, to where that same bullet would touch the rifling. Variations in this distance are not the same thing as base to ogive or boat tail to ogive differences, and to my way of thinking should be the best possible predictor of distance to or into the rifling variations in ammunition loaded with a particular batch of bullets. Opinions?

A related question that I would like to hear opinions on is how much variation in loaded rounds' bullets' distance to or into the rifling (or from touch) does it take to show up on paper. Also, are different ogive styles (tangent, secant, VLD, or double radius) more or less tolerant of this sort of loaded round variations. What has been your experience Have you actually measured loaded ammunition for this variance? I have not, but now that I am better equipped for the task, I will. I guess that I have always ASSUMED that all of my custom short range bullets were uniform, within a batch, because they all came from the same point die.

Some time back a gunsmith/shooter of high skill, told me of a new short range Benchrest shooter that was seeing quite a bit of ogive to base of loaded round variation in his ammunition. The smith modified his seating stem so that it bore further down the ogive from where it had, and the variance was significantly reduced. It would seem to me that if all of the bullets were uniform, that this would not have made a difference. I am pretty sure that the shooter was using custom bullets, and that they would have all been from the same point die, but for there to be the sort of problem that he was having, there would have had to have been significant ogive shape variations. Would this have been caused by differences in jacket metallurgy, or possibly variations is press stroke as the bullets were formed? Could differences of lube have contributed? It would seem that these would be questions for the bullet makers among you.

When I tune I select a load in a speed range that is known to be an accurate node. I then begin by loading three rounds with bullets that just barely touch the lands and continue to load groups of three rounds advancing the bullet by .003 in each three round group. if the bullet - speed combo is going to work it almost always shows up either at .003 or .006. Occasionally a barrel will want a bit more jam but .006 seems to often be where the small round hole appears. If .003 makes a Mickey Mouse face into a small round hole there has to be a compelling reason, eh?

Folks can say all they want about the relationship between bearing surface length and ogive length not mattering but holes in paper will tell one otherwise. For some reason I seem to find a direct relationship and have since I begsn sorting bullets. Bullets of differing surface lengths will shoot together as long as one makes sure they are seated the same length on the ogive where it touches the lands, from my experience.

The most consistent bullets I have Measured to date were made in Waterburry- Farrel. I was sent a sample of 100 to try and every one of them measured exactly the same. I couldn't believe it and still have them I found them so prescious .

Personally I don't care what folks do or what they therorize but when I see the fruits of my lobor by sorting my bullets that is all I need to know.

I can tell all with great certainty that the 100 machine made bullets I have is the only lot of bullets, regardless who made them I have ever sorted that were all exaclty the same.

Regarding making one's stem larger: I have recently been told that if one does this one should drill a small hole through the center of their stem to eliminate any vacuum that might occur from to good a fit between the stem and the bullet. Some say when the relationship between the size of the stem and the bullet get closer to the same the stem may want to stick to the bullets.

One thing is for certain, it is impossable to make ammo that is TOO GOOD. One can draw any conclusion from that they want.

Pete

 

[Greg Culpepper]

The point I was trying to make with the seater stem contacting the bullet way up the ogive was that the ogive on the heavier/fatter bullet is swelled where the ogive meets the rifling(I think the harder to displace lead in that area is the culprit,(harder to displace than a plain jacket wall and a little air up in the bullet nose).So the ogive is changed but the nose where the seater stem contacts it is unaffected. So your seater is pushing the bullet nose down to the same place but the expanded shoulder/ogive of the rogue bullet could be in a different spot than it is with all the others.

Joel,

Your lengthy and inclusive narative on bullet making issues and effects is a real service. Mostly what happens on boards is we ping or ding a narrow little issue and the context is lost or never revealed. Thanks for going to the trouble, you posts are really framing the discussion.

Since it's difficult to measure the ogive variation you describe above with the available tools do you think that sorting by weight (the cause of the variation) would be a usefull method to reduce this variation? In my own shooting i've found much benefit sorting for BS length but if there is benefit to sorting by weight as well it has gotten lost in the noise between my rifle and the target. What do you think?

Greg

 

[Greg Culpepper]

The most consistent bullets I have Measured to date were made in Waterburry- Farrel. I was sent a sample of 100 to try and every one of them measured exactly the same.

I can tell all with great certainty that the 100 machine made bullets I have is the only lot of bullets, regardless who made them I have ever sorted that were all exaclty the same.

Pete,

There is plenty of irony in finding the greatest uniformity where it might be least expected. In one case that's what I found also.

Greg

 

[Al Nyhus]

Boyd and all:

Core seating pressure can have a big influence on the finished b-to-o measurement as does the lead/antimony mix of the core material.

With jackets from the same lot, a finished bullets ogive position...relative to the base of the bullet...can vary considerably depending on how much core seating pressure was used and how 'hard' the cores are. Within a particular 'run' of identical seating pressure and core materials, the b-to-o dimension should remain consistent.

If I seat two cores...one a .5% lead/antimony core and the other a 1% lead/antimony core...there will be a difference in the b-to-o measurement when those two bullets come out of the point die.

But here's the catch and the insidious details of bullet making: Try as I might, those two cores won't be seated with exactly identical seating pressures. Because of the different hardness of the cores, the jackets react differently to each core. The jacket is going to change in length a bit differently with each core and the upper edge of each core is going to end up in a different place relative to the length of the jacket before it's pointed.

Since the bullet making process is an 'expand up' process, the jacket reacts to where the upper edge of the core is...thus influencing to some extent where the ogive is relative to the base...within that lot of bullets using those components.

Now add jacket lots of differing weights, and thus different 'working' characteristics due to thickness and hardness variations, and you can see how things can stack up pretty quickly to give differering b-to-o dimensions from different bullet lots, even though from a performance standpoint there is no difference between lots.

Each bullet maker approaches this differently. Some pay z-e-r-o attention to the b-to-o measurement between lots and simply allow the components to influence what that measurement is. Their bullets shoot great. Others strive for as similar b-to-o between lots and adjust seating pressure accordingly to get those results. Their bullets shoot great. Much of what you can 'do' to influence this as a bullet maker depends on the type of dies used.

These are just some observations after a couple of years making my own bullets. It's a great learning experience that sometimes leaves me with more questions than answers, but is ultimately pretty darn rewarding.

I'm just glad I don't make bullets to sell.........

 

[Pete Wass]

Thanks Al

Boyd and all:

Core seating pressure can have a big influence on the finished b-to-o measurement as does the lead/antimony mix of the core material.

With jackets from the same lot, a finished bullets ogive position...relative to the base of the bullet...can vary considerably depending on how much core seating pressure was used and how 'hard' the cores are. Within a particular 'run' of identical seating pressure and core materials, the b-to-o dimension should remain consistent.

If I seat two cores...one a .5% lead/antimony core and the other a 1% lead/antimony core...there will be a difference in the b-to-o measurement when those two bullets come out of the point die.

But here's the catch and the insidious details of bullet making: Try as I might, those two cores won't be seated with exactly identical seating pressures. Because of the different hardness of the cores, the jackets react differently to each core. The jacket is going to change in length a bit differently with each core and the upper edge of each core is going to end up in a different place relative to the length of the jacket before it's pointed.

Since the bullet making process is an 'expand up' process, the jacket reacts to where the upper edge of the core is...thus influencing to some extent where the ogive is relative to the base...within that lot of bullets using those components.

Now add jacket lots of differing weights, and thus different 'working' characteristics due to thickness and hardness variations, and you can see how things can stack up pretty quickly to give differering b-to-o dimensions from different bullet lots, even though from a performance standpoint there is no difference between lots.

Each bullet maker approaches this differently. Some pay z-e-r-o attention to the b-to-o measurement between lots and simply allow the components to influence what that measurement is. Their bullets shoot great. Others strive for as similar b-to-o between lots and adjust seating pressure accordingly to get those results. Their bullets shoot great. Much of what you can 'do' to influence this as a bullet maker depends on the type of dies used.

These are just some observations after a couple of years making my own bullets. It's a great learning experience that sometimes leaves me with more questions than answers, but is ultimately pretty darn rewarding.

I'm just glad I don't make bullets to sell.........

Your explanation of the process fills in a lot of blanks I had as to the why of things. It all makes sense. You are the first to give a good explanation as to the cause the variations. Thanks again

 

[Joe Salt]

Greg & everyone , let me see if I can get this right. B.S. there seems to be more variation, than ogive to base, that is why I just measure B.S. Then after pointing I run them through a 309 neck bushing, but you're going to have go through a lot of bushing before you find the right one, because they aren't all the same. I used two bullets that I found that were two different sizes fat and just right. I know you're going to ask what size, can't remember long time ago. As for seating and measuring I use J.B. comparator, and Sinclair ogive to base comparator on calipers. I think if your measurments are the same loading to loading and you're getting good results stick with it.

Joe Salt

 

[Greg Culpepper]

Thanks Joe

Greg

 

[Nader]

Joel,

Your lengthy and inclusive narative on bullet making issues and effects is a real service. Mostly what happens on boards is we ping or ding a narrow little issue and the context is lost or never revealed. Thanks for going to the trouble, you posts are really framing the discussion.

Since it's difficult to measure the ogive variation you describe above with the available tools do you think that sorting by weight (the cause of the variation) would be a usefull method to reduce this variation? In my own shooting i've found much benefit sorting for BS length but if there is benefit to sorting by weight as well it has gotten lost in the noise between my rifle and the target. What do you think?

Greg

Greg,
When making bullets one gets to cull out the rogues at four different stages.Core forming,core seating,bullet pointing and final weight check. If a bullet makes it through the first three stages the final weight check will be "dead on".
Working( thinking) in reverse;If the finished bullets weigh differently, then the "problem" must be somewhere in the first three stages! If you didn't make the bullets you don't have a clue as to where the root of the variation lies,but certainly finished weight check is a red light to the fact that a variation exists. So weighing finished bullets is not a bad idea,but if you find a lot of variation,sorting by weight or comparative ogive measurements is just a "get by" approach.As a serious BR competitor you need a better bullet,find one or make one. Ask any top BR shooter to compete in a National match with anything less than the best bullets and barrels in his collection and his chances of winning will be greatly diminished.
Joel

 

[Greg Culpepper]

Thanks Joel,

I have just enough exposure to bullet making with Greg Seigmund of Clinch River to understand that pulling the handle on a bullet press (and reading the feedback coming off that handle), while a seemingly simple act, is actually a learned skill and not dissimilar to "gunhandling" with its subtle but significant variations. There is art that must be layered on top of the mechanical science for the best attainable result. I admire you dedicated souls who can do it all.

This thread and especially your reflections on bullet making have given me additional considerations to apply to my ammo preparation. While considering the talent that converges from barrel maker, gunsmith, powder, brass, scope, bulletmaker and on, I'm reminded of the fractional part I play in forming the group on paper. Seems like a team effort. Thanks guys.

Greg

 

[Al Nyhus]

Al,
The example that I gave was one where there was head to ogive variation, so it would seem that what you have said is not always the case.
Since I invariably seat bullets so that they are longer than touch, and I have a so called gizzy, made with my reamer, I have always had the ability to measure head to rifling contact point variations, it just didn't occur to me to do so. As to the difference between seating stem to rifling contact measurements and the typical ogive to base measurements, I get it. That is why I think that Bob's gauge may be a significant advance.

HI Boyd. You've nailed the issue, nicely. Please excuse my parsing of your quote to get to the meat.

It's important there's no case head-to-ogive differences that are caused by the seating stem....whether a shooter takes things further, or not.

Good shootin'. -Al

 

[Pete Wass]

While we're on a roll Al

can you explain why on some bullets there is a difference in length between where the bullet touches the lands and where the seating stem touches the bullet? It is this difference that causes the problem for me.

Thanks,

Pete

 

[Boyd Allen]

Al,
What I was trying to point out was that when comparing bullets from the same point die, there are variations in the curve of the ogive that can result in different seating depths that are independent of any die problems, and that short of seating the bullets, Bob's gauge is the only way that I know of to look at this, without making an ogive length insert that is small enough to land on the same circle that the seating stem does , using it to measure to the base of the bullet, and then measuring the same bullet with an insert that duplicates the leade angle and diameter, and subtracting, for each bullet. If you go back to where I posted the links to a page on Bob's web site, where he has an account of the accuracy benefits to a shooter who used his gauge to sort VLDs, you will see a concrete example. What has been so hard to convey, without a video, is that his gauge appears to be unique and how it works, and how it does work, even though it is actually pretty simple.

 

[Al Nyhus]

can you explain why on some bullets there is a difference in length between where the bullet touches the lands and where the seating stem touches the bullet? It is this difference that causes the problem for me. Thanks,. Pete

Pete, conventional bullet seaters are not designed to bear anywhere near the bullets ogive origination point. They'll bear somewhere along the point, but still well forward of where the ogive starts.....the ogive by common definition being the tapered part of the bullet foward of the shank diameter.

Using four different unmodified Wilson .30 cal. seating stems, I measured the diameter on one of my .30 cal. bullets at the point where they contact the jacket.
.207
.221
.234
.254

Good shootin'. -Al

editted to clear up 'ogive'.

 

[SGJennings]

Al,

Is the geometry such that any one of those four would have seated bullets to a consistent depth?

Greg J.