Bullet RUN OUT

[Pete Wass]

I believe the issue is around where the seating stem contacts the bullet. On a certain lot of bullets the length from where the seating stem contacts the bullet and where the lands contact the bullet remains fairly constant for that lot of bullets. In a new lot, that distance will again be relatively constant but it is a different distance than the prior lot. Where the ogive ends up in loaded round depends on where the seating stem contacted the bullet. If that relationship between seater stem contact and the actual ogive of the bullet changes, you get different amounts of jam. I don't know enough about making bullets (actual next to nothing) to know why the relationship changes when the bullets are from the same maker/bullet die but it does and it causes differences in the amount of jam. Randy J.

Randy, I am somewhat inclined to agree with you but from my experience in measuring , perhaps 15 K bullets the relationship from the base to where the ogive touches the lands seems to be the determining factor in terms of sorting bullets to have consistent loads. There is a difference in the diamaters in that length . I don't have a comparitor to measure the seater stem to ogive so I can't tell if the two ways to measure are related. The setup I have works for me so I go with it.

I was thinking about this all morning and I recalled what an engineer who runs a bullet making department told me when I asked him why these variations occur. The one thing that stuck out was he said the lube was difficult to mix and get good consistency. If there is an unevenness in the mixture the bullets will come out different sizes ( Liquids can not be compressed - - -). I also was wondering about spring back in the base metals. I don't know if lead can spring back when it comes out of a die but it might. If springback occured in the jackets there would be a void between the core and the jacket; not as likely.

There are lots of posabilities I guess but it doesn't seem to matter rather a Waterburry- Farrel makes em or a human, the variation occur and at differnt frequencies, for some reason we don't yet know.

 

[Boyd Allen]

Waylan,
I thought about that very thing, and for the primary insertion into the case neck, on a short bullet, I am not sure that the stem hitting the bullet that far back would give positive enough alignment. Maybe a secondary seater to move the bullet the last few thousandths with a cone that replacates the leade angle of the rifling and diameters at the top of the lands and freebore, should give quite uniform final seating depth in relation to the rifling. In any case, why doesn't someone measure some loaded 6PPC rounds in the manner I described in the post you responded to, to see if there is a problem that needs fixing...before we go to the trouble to fix it.

 

[Randy J.]

Mr. Allen

The "gizzy" or barrel stub gauge is exactly what I use to measure my jam. When I seat bullets and I don't get the same reading then I don't have the same jam. Again, I think the differences in bullets from the ogive forward to where my seating stem hits to seat the bullet can not be the same if I am getting different reading.

Peter-If you think of the bullet as being made up of three sections--base to ogive, ogive to where the seater stem hits, and the rest of the forward section of bullet in the stem--I think I can explain why your method of sorting works. Your system works because measuring from the bullet base to the ogive is sorting like bullets and I suspect that bullets that measure the same from bullet base to ogive probably have the same ogive to seating stem length also. In other words they have similar characteristics. The jackets all started pretty much the same length so if you have one portion longer than say another bullet then one of the other portions has to be shorter. There is only so much jacket length. Does that make sense? Randy J.

 

[Waylan Kisor]

Waylan,
In any case, why doesn't someone measure some loaded 6PPC rounds in the manner I described in the post you responded to, to see if there is a problem that needs fixing...before we go to the trouble to fix it.

Probably the best solution!! If a problem does not exist do not make one. Food for thought. Take a Wilson seater, bore a few thousnadths out of the area above the point at which the end of the case stops, then make the seating stem correspond to this larger hole with the contact point of the stem same as the contact of the lands.

 

[Pete in Surry]

Yes, it makes sense

The "gizzy" or barrel stub gauge is exactly what I use to measure my jam. When I seat bullets and I don't get the same reading then I don't have the same jam. Again, I think the differences in bullets from the ogive forward to where my seating stem hits to seat the bullet can not be the same if I am getting different reading.

Peter-If you think of the bullet as being made up of three sections--base to ogive, ogive to where the seater stem hits, and the rest of the forward section of bullet in the stem--I think I can explain why your method of sorting works. Your system works because measuring from the bullet base to the ogive is sorting like bullets and I suspect that bullets that measure the same from bullet base to ogive probably have the same ogive to seating stem length also. In other words they have similar characteristics. The jackets all started pretty much the same length so if you have one portion longer than say another bullet then one of the other portions has to be shorter. There is only so much jacket length. Does that make sense? Randy J.

when the seating stem has to be moved to give the same loaded OAl, measured from the base of the case to where the bullet will touch the lands the entire ogive has to be appearing in a different location on the bullet BUT what is puzzling to me is the relationship of all three to each other. The straitht wall portion of a bullet should not be a contributor to the OAL of a loaded round and I don't believe it is but it is interesting that bullets with like straitwall lengths seem to also have the same relationship to the other measurements.

A very simple way to make the entire issue a workable one is to segregate the bullets; like size to like size. All the bullets shoot eaquily well as long as one can seat them to consistent lengths. This is all we are talking about. It would be nice if we didn't need to sort them but I feel I must. I don't see this as a quality issue but it is somewhat of a quality control issue. How more consistency can be achieved is another question to be asked.

 

[mikecr]

Mr. Greens tool looks to be exactly what I made. I used a Kevin Kram(sp) meplat trimmer, bored it up one cal to bore diam instead of groove, fitted with an internal plug(like a seater stem), and mounted an indicator like he did to read off the back of the plug.

I could go from bullet to bullet in a tray seeing variance. But my machinist was not careful to keep all dimensions to my standards, so he needs to do it again.
Maybe I'll stop waiting for my machinist and buy Bob's since he beat me to the same end. Great find

 

[Al Nyhus]

Al,
I'm not sure. If the point on the two bullets where the tapered nose meets full caliber diameter is at the same position on each bullet then the seating depth should be the same. I just don't see where the reference point for a loaded round can be any other point on the bullet than that one. If that varies among bullets due to lube or whatever other variable in themaking process then seating depth will vary by the difference between the positions. Am I missing something here? I think what you are saying is that this point will not vary among bullets from the same die? Thanks

Greg, a couple of things to keep in mind.
- A bullet doesn't engage the lands at "...the point on the two bullets where the tapered nose meets full caliber diameter" (from your post). This area is simply the beginning of what, by definition, is the 'ogive' of the bullet. There is no one single point on the bullet that is 'the ogive'. The entire portion foward of shank diameter is 'the ogive'.
- The bullet engages the lands at a diameter quite a bit smaller than the shank diamter of the bullet. In a .30 cal. example, the shank diameter may be .03084, but the diameter of the lands will be in the .3000 range. The groove diameter will be around .3080 in most .30's.

There's also the matter of semantics involved in this discussion that makes it frustrating to explain and for some to understand. Here's a good example:
"The meplat lenght(sp) ain't an issue".

Well, no..... the "metplat length" isn't an issue...because the metplat is the flat end of the bullet. It has no length.

This is really not as complex as some would want to make it.

Good shootin', buddy! -Al

 

[Jay Idaho]

Boyd you struck a note. I have thought about why no one makes a seating stem that engages the bullet at the point it touches the lands. Seems like some of the die makers have missed something or maybe I have. In a Wilson type seater that is made for your chamber and a seating stem of this type would be something of interest.

When I tried making seater stems that contacted the bullets "at the point it touches the lands" the bullets had a tendency to stick in the seater stem and to be marred somewhat at contact point. Maybe with very little neck tension, it would be less of an issure. If I had access to an EDM I'd make seater stems using bullets for electrodes.

 

[Pete Wass]

There is no reason

When I tried making seater stems that contacted the bullets "at the point it touches the lands" the bullets had a tendency to stick in the seater stem and to be marred somewhat at contact point. Maybe with very little neck tension, it would be less of an issure. If I had access to an EDM I'd make seater stems using bullets for electrodes.

To do anyhing other than measure bulllets using a comparitor like the one Tubb or Hart or homever sells. This device will allow one to sort their bulets so that they will be able to achieve consistent seating depths. It is truly that simple; money well spent.

 

[j mckinnie]

base

of the case is seating depth base of bullet is irrelevant to seating depth

 

[Pete Wass]

Your theory

of the case is seating depth base of bullet is irrelevant to seating depth

for every logical reason one can think of should be correct BUT - - - if one sorts their bullets by measuring them from base to ogive, it matters. The base is the base of the measurement.

 

[Boyd Allen]

I think that the key point being discussed is whether the points at which a comparator or seater stem make contact with the bullet give a good indication of the consistency of the relationship of the bullet in a chambered rounds relationship to the rifling. If, for instance two rounds show a difference with the comparator (ogive to case head), will there be the same difference in the amount of rifling engagement? There has some indication from the responses in this discussion that comparator and gizzy measurements may not agree, and that the difference in where the seater stem hits the ogive and where the ogive contacts the rifling may be giving us problems in round to round consistency in the position of the bullet in relation to the rifling. I know that the next time that I go to the range (where I do my loading) I will measure all of my loaded rounds with a gizzy and also with a comparator, and write both down for each of say 20 rounds. This should tell me if there is a problem. I am hoping that there is not, but if there is, most of us will have the same issue to deal with. It's kind of like when concentricity gages first became easily available, and we had a new area of quality control to consider. Although most of us have had the needed tools to make this comparison, it may not have been looked at. The good news is that, if there is a problem, and we fix it, we will have better ammo.

 

[R. G. Robinett]

OK, I lied . . .

I finally found a pastime more boring than bullet making - MEASURING/Comparing loaded ammo! As I suspected, I wasn't missing much - well, except for the boredom!

I may have stated that I would measure 100 bullets . . . if I did, say I'd do that many, I lied - the boredom quickly turned it into 1/10Th of that quantity . . .


Here's what was done:

1) Using a PPG thirty caliber "throater" reamer (1.5 degree or, 3.0 deg. included throat angle), a full cone "throat" was reamed in a piece of aluminum. This, as opposed to using a barrel stub, would elininate the possibility of burs on the trailing edge of the lands,thus should provide a precise representation of a 1.5 degree throat.

2) I then grabbed a handy box of point-up die/set-up bullets - bullets used to both set-up and "tweak" the point die for the correct/desired meplat closure. These bullets represent several YEARS of point-die set-ups and many different jacket (material/length/weight) Lots (all J4s though). (Note: the bullets were all of the same nominal weight and ogive: 187 Gr. - 10 ogive.) Bullets were selected [from the box] at random.

3) A single 30x47 HBR case was selected , decapped, and neck-sized. Then, a bullet was seated and the case-head to cone contact length was recorded. This was repeated 9 more times.
After the tenth measurement (to assure some sort of consistency, the case was neck-sized each time), the EXTREME variation in length, as measured via a Mitutoyo 6" ABSOLUTE Digimatic caliper, was 0.0025" - not much off the expected "error" range of a caliper! Here are the recorded lengths: 1) 0.0265; 2) .0275; 3) .0260; 4) 0.0270; 5) 0.0255 (shortest recorded); 6) 0.0280 (longest recorded); 7) 0.0260; 8) 0.0270; 9) 0.0280; 10) 0.0280.
At this point, I decided that I was wasting time - I'd shoot any of them and be unable to tell the difference on target.

4)Then, at random - that is, no correlation to the initial sequence - using the same (1.5 Deg.) cone, I measured the bullets only - the dreaded base to ogive dimension. The extreme range was 0.0145"! This is 5.8 times the variation of the loaded rounds - where's the correlation? For the record, the shank lengths varied from 0.5850" to 0.5995" ! Note: in no particular order - except as measured - here are the individual base to ogive dimensions; remember, these are from numerous material and set-up Lots: 1) 0.5995; 2) 0.5850; 3) 0.5970; 4) 0.5925; 5) 0.5850 (shortest shank); 6) 0.5915; 7) 0.5995 (longest recorded) ; 8) 0.5915; 9) 0.5950; 10) 0.5900.

Thus, my conclusion: either some of the methods are flawed, the dies (sizing/seating or, both) are an issue, and/or, I'm extremely fortunate, and my loading equipment is exceptionally good - you be the judge. RG

 

[Boyd Allen]

Thanks Randy,
The other part of the test would be if you had measured with a comparator, and your aluminum throat for each loaded round, to see if the comparator variations tracked with the throat measurements. In any case, thinks for the info. With a smaller ogive number, single radius ogive bullet (more sensitive to seating depth, I think) How much variance would it take to see it on a target…if you were on the edge of tune, and the variation took you in the wrong direction?

 

[Dave Tooley]

Randy

Dittos from here.

There is a combination of about three things that can cause variations in seating depth.
1. Variations in neck tension.
2. Variations in the chamfer on the neck. either increasing or decreasing the amount of pressure it takes to start the bullet in the neck. I like a 14 degree carbide burr
3. The fit between the seater stem and the ogive. To small a contact area and the first two have more of an effect on the seating depth.

Dave

 

[mikecr]

RG, wouldn't .0025 variance to the lands be significant?
It is in my view.

Also, I would expect far less error than ~ .0025", from modern calipers. Did you get the numbers right?

 

[R. G. Robinett]

RG, wouldn't .0025 variance to the lands be significant?
It is in my view.

Also, I would expect far less error than ~ .0025", from modern calipers. Did you get the numbers right?

" . . . wouldn't .0025 variance to the lands be significant?"
Within a single Lot, I'd tend to agree - but if you look at what I did, you'll see that the samples compared were a "worst-case" expamle - from a significant periord of time and jackets of [now] unknown [J4] production Lots - base upon THAT, I'd say, these are insignificant variations - again, just look at the base to ogive lengths and try to imagine a correlation. The sole reason for keeping such bullets is to quickly reset a point-up die to 'inside the ball park'!

A caliper is a caliper - they are accurate and repeatable to 0.001" - a range of 0.002 would be completely within the expected 'norm" - especially when measuring at attribute, which is potentiallly affected by misalignment, a degree of 'springiness' and the subjective nature of 'feel'.

Further, as hinted at by Dave Tooley, once the cases are resized, and a bullet seated, how do we know that, during the processes, the entire neck wasn't set back to a measurable degree? In the other examples, prior to seating a bullet, was every shoulder comapred for set-back? To make certain that the necks have not 'caved-in' slightly [under seating pressure, were/are the case OALs verified prior to seating? If, relative to the case-head, the shoulders are bumped back, we have now introduced the potential for variable 'spring-back' . . . since the neck is attached to the shoulder, the neck, which is now holding the bullet could be bouncing along the axis . . . then, the pressure of seating the bullet could introduce yet another change in the length! The bullet seems to be carying all of the responsibiliy for all of the potenital variables. There is a strong possibility that an attribute entirely different [than the bullet ogive] is being measured.

Lastly, assuming that for a given bullet lot, there was a range of 0.003" from the longest to the shortest shank/bearing length - using my usual method of tuning ( a jam-seat), If I did get a barrel, which was so sensitive to ogive variation that it showed up on target, I'd be looking for a new barrel . . . fortunately, I've yet to own such a finicky beast. RG

 

[mikecr]

I know you're bored, but let's back up.

For one, it's completely unbelievable to me that modern BR shooters would utilize so much neck tension, that bullet seating would distort cases. And 2.5thou(or less) could surely affect tune for those not jamming. There are BR shooters not jammed right?

I'm sure that custom point blank BR bullets are very consistant. Nobody has suggested otherwise. But there will eventually be variance, of some amount, even among these.
With enough measured, it's reasonable that there would occasionally be an ogive that departs from the pack. There might even be a bell curve observed, significant to your standards or not. Right?

I imagine this is probably an area more appropriately considered by long range BR shooters, as the diversity in bullets and loads is much greater. Maybe it just doesn't matter here.

 

[alfred.milner@c]

hello boyd how does the hoeh's ultimate bullet straightenr compare with the newer tools of today thanks....

 

[twentytwoguy]

If the distance from the bullet ogive to the lands (or whatever the first contact point is in your barrel) is suspect and actually critical for accuracy than it would seem the most important measurement for that parameter would have to be taken after the bullet is seated and then measuring the loaded round with a comparator that measures from the base of the case to the ogive of the bullet since this seems to be the final measurement that all of the other prescriptions are trying to indirectly achieve.

There was talk last year about this and it seemed that some of the popular long-range shooters were even seating a little long and then measuring and bumping the "case base to ogive" seating depth for each round using a micrometer seating die to dial in bumps for each round.