Let's talk about bullets

Pete Wass

Pete Wass

Well-known member
In my quest to achieve perfectly seated bullets I was lead to try to discover why it is nearly impossible to seat bullets exactly the same length measured from where the bullet will engage the lands to the butt of the case that engages the bolt. I realized it is because the ogive shape of the bullets are the cause. So comes the question, why is there a variation in bullets in that area?

I have concluded it' is caused by the cores not being exactly the same and when the bullets are swaged into the jackets, any extra amount of lead is forced into the ogive slope thus causing a variation of the overall length of the bullet.

So comes the problem of being able to achieve exact OAL's because of the design of most seating stems. Most seating stems engage the tip of bullets. If the total bullet is longer, erratic seating will occur.

So. how far afield am I? I have proven to myself over the years that exact seating depths are imperative to absolute accuracy. Have others thought about this and acted on a solution?
 
The bullet "tip"/me'plat should never touch the seater stem. Bullet cores, within +/- 0.1 Gr. will vary less than 0.002" in length - very unlikely a cause of nose length:diameter variation. Back to the initial point: if the me'plat touched the stem cavity, you can/should expect relatively LARGE variation in case-head to ogive dimensions: variation in bullet OAL , of up to 0.010" is common. Thus if the "tips/me'plats contact the stem, one can expect variation in, "seating-depth".

The cure is to assure that the "tips" cannot contact the stem: one method is to drill the stem cavity to a greater depth, then, lap the stem to ones bullet of choice. The contact location should be well down the nose from the tip/me'plat. RG
 
I didn't express what I intended to say very well. I did not mean that the tip of the bullet touched the inside of the stem. What I wanted to say was the conventional seating stems touch the sides of the MePlat near the tip of the bullet. I guess without knowing the language of bullets very well I should have been silent. I had a conversation with an engineer of one of the "Old Line" die makers about what I was trying to say and he said they knew the problem existed but did not want to do what was necessary to correct the situation. Seating stems that touch the bullet close to where the bullet will engage the lands are the cure. To that end, I kept buying stems until I found what I was looking for. For me, a 30 cal stem is right for a 6mm bullet. I think I am using a 358 cal for 30's. Much more consistent.
10ring said:
How much variation are you seeing?
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It isn't unusual to see .003" often when using conventional stems.
 
Pete. First use a dial caliper. The digital just messes with you. #2 If I remember you use factory bullets maybe. The ogive is going to very. #3 If the core is too big than lead would come through Hollow point. I have seem this on custom bullets. Won't say who. #4 The bullets I make 7 and fat 8 ogive. Seated with the Wilson die. Seat the same. The stem contacts closer to the point. The Sinclair ogive nut gives a good measurement. And is around the ogive. #5 The lands of a barrel and the ogive nut are 2 different things. Close but different.
And the old guy says don't worry about the point, just shoot em.
 
I think the good question that has been asked is are you shooting factory bullets or custom/hand swaged bullets? If you are shooting factory you will probably experience a fair amount of base to ogive differences due to a slew of factors. If you are dealing with custom made bullets, your bullets should be much closer in base to ogive length. However, a custom bullet maker can change this dimension...they can make bullets that are all over the map by not keeping close attention to the amount and consistency of lube application during the point-up process. Consistent lube application is key to keeping dimensions consistent.
 
Liseo said:
If the stem touches closer to the tip than touching where the ogive touches the lands, wouldn't it give better alignment, reducing runout?
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So long as there is no way the first 0.030" (+/- a little) of the "tip can get into the act, I agree.
That said, using a few bullets, any/all [new] seater stems are for a near perfect match, and dedicated to specific point-die nose configuration. RG
 
Bro.D said:
I think the good question that has been asked is are you shooting factory bullets or custom/hand swaged bullets? If you are shooting factory you will probably experience a fair amount of base to ogive differences due to a slew of factors. If you are dealing with custom made bullets, your bullets should be much closer in base to ogive length. However, a custom bullet maker can change this dimension...they can make bullets that are all over the map by not keeping close attention to the amount and consistency of lube application during the point-up process. Consistent lube application is key to keeping dimensions consistent.
Click to expand...
I have a granite based indicator set up I use to segregate bullets into .001" increments. using a fixture the bullets sit in. It is rare to find a lot of bullets that all measure the same. All the bullets will shoot well as long as they are seated exactly the same. Segregating them just makes it easier to seat them correctly. I do not use Factory bullets . I suppose it may appear I an a neophyte but I have been doing this for 20+ years. When people say they have bullets that won't shoot, it's likely because the ogive lengths for the seating stem they are using are very random in length. It doesn't take a lot of time to go through 1000 bullets and segregate them. I have always found it well worth doing.
 
For the 7-10 ogive bullets, the VLD style seater stems are a good place to start if using a Wilson style seater. Lapping as suggested by Randy should be S.O.P. for consistency.

Pete...are you using Wilson style seaters?
 
Al Nyhus said:
For the 7-10 ogive bullets, the VLD style seater stems are a good place to start if using a Wilson style seater. Lapping as suggested by Randy should be S.O.P. for consistency.

Pete...are you using Wilson style seaters?
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Hi Al. I tried the lapping thing. I had to buy 2 new stems. That was to get rid of the little mark. I went real slow. And started to not like the results. And it got worse as I went along. Little bit here little bit there. New stems are fine.
 
R.G. Robinett said:
So long as there is no way the first 0.030" (+/- a little) of the "tip can get into the act, I agree.
That said, using a few bullets, any/all [new] seater stems are for a near perfect match, and dedicated to specific point-die nose configuration. RG
Click to expand...

On my own, I feel more comfortable with a chamber type seating tool having a stem channel/bore matching the bullet dia, and a stem drilled/bored/smoothed that makes contact with the bullet as near as possible from land dia and leaves most of the [|tip then point] free inside the stem.


One thing I have done for a cast bullet lubrisizer was a composite bullet stem. Started with a ""blank"" being just drilled deeper than the nose length, a tad smaller than caliber, then drilled / bored a little cylinder to support the stem, the bullet and a piston (rod to push on the bullet base), glued the stem hole with loaded epoxy, placed everything in the "guiding" cylinder, C-clamped and let cure vertically so that the epoxy ""flows down"" along bullet nose. Of course, parts got waxed for de-molding, except stem hole. Once FULLY cured, clean the stem entry with a dremmel or go to the lathe, if needed. Tightness is achieved in pushing the bullet against the stem hole, no leakage should occure.

For a tipped bullet, I would go back to the lathe and drill a small hole to make sure to free the bullet tip area. An epoxy "belt" will remains, matching perfectly with the lower nose shape.

My composite stem sized thousands of lead bullets along the years.


@Al Nyhus : ""Lapping as suggested by Randy should be S.O.P. for consistency."" What does S.O.P. means ?

@zippy06 : don't understand the "little mark" thing. One may start lapping with some of a grit to "eat" material but shall finish white polished at minimum, cleaning/degreasing thoroughly between each grit size change, changing grit "driver". Where did the mark came from ?

@R.G. Robinett : VERY nice shooting Sir.

Oliver.
 
Oops, 3 other points that should never occur in our little world :

- HUGE variation in neck tension can lead to "Davidson" variation because of flexing the case shoulder, the shoulder springs back,

- Bullet base bumping on dreaded doughnut, again flexing the shoulder,

- Light neck tension and compressed load with the compressed load pushing the bullet out more or less.
 
Pete Wass said:
.............. It doesn't take a lot of time to go through 1000 bullets and segregate them. I have always found it well worth doing.
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Agree. Did it for almost a decade and it changed my results.

Remember my evenings sitting at a the desk with a bunch of cleaned ice cream boxes in front of me, each wearing the B/O measurement increment. I used 0.002" increment.

That was a very interesting experience.

The distribution was usually quite Gaussian (see how much the boxes are filled).

Did encountered some dual distribution from time to time, tasting a bit like mixed batches.

The width of the distribution (number of boxes needed to "cover" the entire batch) vary a lot from maker to maker, but there was ALWAYS some ugly ducks sitting aside the boxes row, with a B/O totally out of distribution. Except for 1 maker allegedly selling products that 'll never work.


Since I put my finger in the bullet making gears, I stopped this "industrial" measuring. Just check some bullets here and here to feel better in my anxious mind.
 
OliveOil said:
Agree. Did it for almost a decade and it changed my results.

Remember my evenings sitting at a the desk with a bunch of cleaned ice cream boxes in front of me, each wearing the B/O measurement increment. I used 0.002" increment.

That was a very interesting experience.

The distribution was usually quite Gaussian (see how much the boxes are filled).

Did encountered some dual distribution from time to time, tasting a bit like mixed batches.

The width of the distribution (number of boxes needed to "cover" the entire batch) vary a lot from maker to maker, but there was ALWAYS some ugly ducks sitting aside the boxes row, with a B/O totally out of distribution. Except for 1 maker allegedly selling products that 'll never work.


Since I put my finger in the bullet making gears, I stopped this "industrial" measuring. Just check some bullets here and here to feel better in my anxious mind.
Click to expand...
I have always found the majority of the bullets will be with .001" of each other but some lots tail off as much as .006". The out lyers shoot fine but need special attention when seating. The only reason to sort them.

P
 
Al Nyhus said:
If the bullets are from the same point up die, any base-to-ogive differences only change how much bullet is in the case neck. -Al
Click to expand...

Very interesting statement Al.

I would agree 100% should the bullet stem contact zone on the bullet matches with the beginning of the engraving area on the bullet.

If not, with usually a stem contacting somewhere in between the engraving start dia and the tip, I will doubt until someone shows me 2 bullets profile measurements, one with the short B/O and one with the long B/O.

I doubt the B/O variation to be exactly copied or translated/slid all along the nose, or reproduced along the nose in a way that a "long" B/O exactly has a THE RIGHT "fattest" or "highest" ogive SO will therefore be seated deeper, so that the ready to fire bullet will be in the very same position towards the rifling whatever the B/O, short or long.

Considering that the just pointed bullet is caught in between the ejector pin hole and the pointing punch which ends the pointing stroke being in the very same position at every ram stroke, a B/O variation MEANS an ogive profile variation.

On my own, I measured bullet batches with a B/O distibution as wide as 0.03" (aka 0.8mm), sometimes with black sheep even farther out.

How is that possible considering the bullet making process, I cannot say, I do not understand how that is possible, except not coming out the same die or same die setting, all this I would consider as a Crime against Bench Rest Spirit.

We had a talk about cleaning / seasoning dies using alcohol and running the first products in the "alcoholic" with some extra lubing. BUT even my first of, segregated bullets, pointed from segregated "first of" core seated jackets, don't show such a variation.

But 0.03" B/O var exists, I measured it quite often. There are out there batches of bullets showing a very sharp B/O Gaussian distribution and some others showing a very flat distribution or double distribution.

So I have a doubt. And just like @Pete Wass, I can assess sorting bullets by [0.002" B/O max var] subgroups DID improve my results.

But once again, since I make my own, B/O shows ALL of them to be well into 0.002" with almost all within 0.001" so I did stop that measurement with my bullets.

And Gents, let me take this opportunity to thank all of you who shared their experience and knowledge here for decade(s) and more recently brought me their support and very valuable information.

Olive.
 
Some time ago, I made a simple ogive profile-to-base checker for my .30's. Rather than indicating from one thin area around the circumference of the bullet, the contact area is the entire nose of the bullet. It makes you rethink the whole base-ogive measuring thing.
 
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