Consistency applied.

[NC_JEFF]

Thanks for this thread. I'm posting it in my caring notes asap, right inside the front cover.

JD

[MBTcustom]

This is the method I use Mike. LOL!
This is a casting session using Linotype. I quite three times to yak at people on the phone in the middle of this. There are no culls. This is the whole run, and I just finished about an hour ago.
Attachment 131799
Attachment 131800
I think I'll throw those seven stragglers back in the pot.

Now, I can get pretty close to this consistancy with any alloy in my possesion, but if I do anything different, if I move ten degrees off with either the mold temperature or the alloy temperature, if I dwell ten seconds longer or slower, the base of the bell curve gets wider, and there is nothing that will stop it from doing so.
Now granted, it may only add 10 bullets to the duds, but you have to figure that when you increase the inconsistency of your bullets, you increase the odds that one of the ones you kept will be off balance, or damaged in some way that you cannot measure except with points lost, targets missed, or groups blown.

In this case,
I was using a PID controller on my Lee Pot
I had an NOE temperature gauge on my mold (awesome tool to improve consistency BTW)
and I had a timex watch laying right between the hot plate and the lead pot.
A couple days ago, I used this method to systematically pin point each part of the equation, and today, I walked up and did this.

Pot was at 740 degrees.
Mold was at 383 to 388 degrees and the hot plate was adjusted to maintain that temperature.
Cadence was exactly one minute per pour. Filled at 0, cut at 23, dropped at 27, shut at 30, paused for 30, and repeat.
Spout was primed for one second.
Alloy was started in the sprue hole by clipping the far edge of the hole, centering smoothly, and clipping the near edge as the pour was finished, and the puddle was about the size of a nickel:
Attachment 131810
Not a bad way to make a deal with a Lee pot for precision.

[detox]

I try to cast with two cavity mold only and separate bullets by cavity. Then weigh and bag bullets from each cavity.

I like casting with simple Linotype, but Magnum birdshot will cut cleaner at base of bullet without voids. I must cast HOT to get good fillout like linotype. The arsenic in birdshot will help get bullets super hard when heat treating. Super hard is needed for high velocity. Linotype is not hard enough.

[MBTcustom]

I try to cast with two cavity mold only and separate bullets by cavity. Then weigh and bag bullets from each cavity.

I like casting with simple Linotype, but Magnum birdshot will cut cleaner at base of bullet without voids. I must cast HOT to get good fillout like linotype. The arsenic in birdshot will help get bullets super hard when heat treating. Super hard is needed for high velocity. Linotype is not hard enough.

Indeed so. It's a misconception that Linotype is hard as diamonds. It's only 22BHN! Now the stuff is brittle, but only past a certain point, and only in a "tensile strength" way. The alloy actually engraves like butter.
I suppose that's why Larry and Bjorn have been able to break 2950 and 3100 FPS (with accuracy) using that alloy.

[detox]

Adding linotype makes a lighter weight bullet. Not good for long range accuracy.

[MBTcustom]

Adding linotype makes a lighter weight bullet. Not good for long range accuracy.

This thread is focused more on accuracy at the bench that can be used on the range as the situation calls for it. So far, I have demonstrated casting consistency here with three different alloys (50/50, 95.6/2.2/2.2, and Linotype). I have also created bell curves for Lyman #2, and COWW.
The bullets from each of these were consistent, and now that they have been rendered perfect in shape, size and weight, they can be heat treated, or annealed to my pleasure, and tested in the same scientific manner on the range to determine what works and what we only wish (or thought) would. No range test can be relied on though, if consistent bullets are not being used to perform that test.
This latest example just happened to be Linotype. That doesn't mean it's what I think is the answer to all my casting needs. If there were an alloy that I would attempt to put into that narrow and confined slot, it would be COWW+2%.

[Hannibal]

I'd like to add another vote for *sticky* status. This is good stuff here.

As for results, well, I've definately learned something here. It's going to take another casting session or 2 to sort out just what though.

[cbrick]

Actually Detox I debated that (birdshot mixed with Lino as the arsenic would allow heat treating)

It's antimony that allows heat treating in common bullet alloys. Any Pb/Sb alloy can be heat treated for additional strength. Arsenic (As) will act as a grain refiner in a Pb/Sb/As alloy and result in a higher BHN than binary Pb/Sb. To say that As allows heat treating is incorrect and in effect is saying that heat treating cannot be done without it.

Rick

[Jevyod]

Excuse my ignorance, but what do you mean by prime the spout? I have never read about this before???!!!

BTW excellent post Tim! Can't wait to apply that when casting for my 358!! I also vote "sticky"

[Bjornb]

You prime the spout by opening it for a very short amount of time (maybe 1 second) and dropping the lead on the sprue plate and not in the hole. This ensures that the lead going into the cavities is all of a uniform temperature, since the lead sitting in the spout between pours will be slightly colder that the main contents of your pot. A small detail, but it adds up to consistency with all the other small details.

[prs]

[QUOTE=cbrick;3150887]It's antimony that allows heat treating in common bullet alloys. Any Pb/Sb alloy can be heat treated for additional strength. Arsenic (As) will act as a grain refiner in a Pb/Sb/As alloy and result in a higher BHN than binary Pb/Sb. To say that As allows heat treating is incorrect and in effect is saying that heat treating cannot be done without it.

A trace of arsenic is a wonderful catalyst in the quenching of lead alloyed with equal adjuncts of Sb and Sn. I believe you can refer to the Lyman Cast Bullet edition just prior to the current edition. It seems that most lead has a trace of arsenic in it like it or not, but I am not sure of that.

prs

[MBTcustom]

I have a ladle resting under the spout of my pot, and below the block shelf. Before I put the mold under the spout, I run a 1 second stream into the ladle. This heats the spout and insures that the cool alloy in and above it, is cleared.
Immediately after shutting off the stream, the mold is placed under the spout and the first cavity is filled, the stream is stopped, the second cavity is filled, the stream is stopped, etc etc etc.
This was the single biggest thing that brought multiple peaks in my bell curves into one single peak.
Here are the two curves that I used a year ago to learn this:
Attachment 131863
Attachment 131864
Obviously, at this time, there was still a lot of things I was doing wrong that made my consistency rather shoddy, but you can also see how making that one change actually had an observable effect on the bell curve. I never could have seen it otherwise.
That's the greatness of this method. It's not all clear, or all fuzzy. Using the bell curves to improve your casting is simply a fuzzy picture that gets more focused or less as you make changes. This is why I used the example of the eye doctor trying different things and relying on your simple answer of "better or worse" to dial in an exact prescription out of a staggering number of variables. We are doing the same thing, and this method allows you to see instantly if what you just did different was "better or worse".

[buckwheatpaul]

Great post expecially for new casters and older caster that have been out of the casting business for a while.....THANKS!

[MBTcustom]

The problem with weight sampling - you don't know if it is a deformity or just a larger dia. boolit.

I would prefer to have neither.
When you cast 300 bullets and have less than 1% variance in weight, and all of them look superb, it is a fairly safe assumption that most of the bullets in that narrow .3 grain spread are identical in more ways than not.
However, that is a much shakier assumption if 25% of your bullets miss that narrow field of acceptance.
That said, if you believe that a large bell curve such as demonstrated in the OP will shoot just as consistently as those in a small bell curve such as I just posted, then your opinion will be either validated or invalidated by your targets and what you are trying to achieve.
For instance, if all I was concerned with is putting five shots into a 2" group at 100 yards (which really is not all that bad of a group) at normal CB velocities, then none of this would appear to make any difference to me. But if you want to shoot 20 shots into a 1" group at 100 yards at 2700 FPS (my personal goal) then you might find that using this system is one way to get you there as it pertains to your bullet casting.

The weight itself is not the issue. I think that if weight were all we were concerned with, then anything in a 2 grain spread would impact very close together downrange. But I'm not measureing weight for weights sake alone. If that were the case there would be no reason for the bell curve. Rather, I am using the bell curve to plot the weights of the entire casting session and using it to determine if I am achieving consistency as it pertains to the variables I have control over (I'm really not concerned with the variables I do not have control over except to attempt to overcome them with the variables that I do have control over).
Because it is a scientific fact that if any part of the mass of the bullet is changed, it will have a direct effect on the weight of that object, and since the shape of the object is set by the precision mold we are using, the only way the weight can possibly change is by being either more or less massive with the same shape, or harboring a void within the object, or a combination of the three.
The voids are the main thing I want to eliminate, but the problem with them is that they cause such a minute change in the weight of the bullets that they are easily hidden in the inconsistent weight of the bullet. Therefore, I concluded that I would eliminate the variances in weight of the bullets, and improve the consistency of my bullets to the point that I could observe a void in the bullets with a scale and that is what I have done in a nutshell.

If you think about it, the only way that bullet could become truly imbalanced is if there is a void present.
Based on the consistency that I am achieving now (rivaling jacketed bullet consistency) I feel very confident that the scale is not only telling me that my bullets are the same weight; its also telling me that my bullets are the same diameter, the same length, the same shape, and they are balanced as well.


That said, I confess I have not attempted to intentionally cast in a way that I now consider substandard to see if my groups open back up to where they were before I developed this method.
I assume that to be the case, and honestly I see no reason to use bullets that are horribly inconsistent in weight (and who knows what else) if I have the knowledge of how to cast better, which I do.
I have fully disclosed how I achieved this level of accuracy and consistency so that those who have a desire to shoot excellent bullets in their rifles have the knowledge of how to do so.

Thank you.

[Jevyod]

Not sure if this is a dumb question or not. If it is, I apologize! How much difference does ambient temp make a difference? Say I cast in the summer, with temps around 80. I get everything figured out, and discover that I need 20 seconds for the sprue to freeze, then a wait of 25 seconds before refilling. Now say I kept all the records, and wanted to cast in the fall with temps around 50. (unheated shop) Can I go by what I did before with warmer temps, or will I have to start over. In other words, do I need records for different temp variations in my shop, or not? Hope this makes sense....

[cbrick]

Not sure if this is a dumb question or not. If it is, I apologize! How much difference does ambient temp make a difference? Say I cast in the summer, with temps around 80. I get everything figured out, and discover that I need 20 seconds for the sprue to freeze, then a wait of 25 seconds before refilling. Now say I kept all the records, and wanted to cast in the fall with temps around 50. (unheated shop) Can I go by what I did before with warmer temps, or will I have to start over. In other words, do I need records for different temp variations in my shop, or not? Hope this makes sense....

Not a dumb question at all. You can keep the alloy in the pot at the same temp easy enough but the air temp your casting in will have a profound effect on mold cooling between pours and even if the mold can get or stay at proper casting temp if it's cold enough air temp. Mold temp consistency or lack of has a profound effect on bullet weight consistency during a casting session and in different casting sessions. So actually that's a good question.

Rick

[MBTcustom]

Not sure if this is a dumb question or not. If it is, I apologize! How much difference does ambient temp make a difference? Say I cast in the summer, with temps around 80. I get everything figured out, and discover that I need 20 seconds for the sprue to freeze, then a wait of 25 seconds before refilling. Now say I kept all the records, and wanted to cast in the fall with temps around 50. (unheated shop) Can I go by what I did before with warmer temps, or will I have to start over. In other words, do I need records for different temp variations in my shop, or not? Hope this makes sense....

Watch your puddle freeze time and the color of your bullets etc etc. They will guide you in no matter what the ambient temperature is. However, you may have to adjust some of the other things to get perfect consistency back.

[btroj]

Wow, cleaned up and reopened already.

[btroj]

Even the accuracy gurus at the CBA aren't in agreement on the need to weigh sort. They might be on to something.

Have you posted this over there to see what they say?

[MBTcustom]

Even the accuracy gurus at the CBA aren't in agreement on the need to weigh sort. They might be on to something.

Have you posted this over there to see what they say?

Once you know where to run and have written down how your mold prefers to be run, it's no longer necessary (which was the reason for me starting the original thread if you'll remember).
If you know where your mold likes to run, for 99.9% of the shooting we do, you can rest assured that what drops from your mold is usable product with no discrepancies. Like that last run I made for instance. I would gladly shoot every one of the bullets in that bell curve without a second thought if I were shooting well below the RPMTH and going for low speed solid accuracy. There were only 7 that missed the target consistency of +-.1 grains, and since those seven were so close to target, I feel very sure there is very little wrong with them.

I'm not recommending using a scale to find the faults in your bullets (although plenty of faults will be seen), I'm recommending using the scale to find the faults in your method and process. Given a little time, it works very very well to that end and I benefited greatly from it in 2014 and so did several other people I told about it, and who helped me develop it (like sgt.mike).
In fact, it worked so well for everyone involved, I thought it might just be a benefit to someone here on the forum. I have tried to word it as clearly and thoroughly as my vocabulary will allow.
So now we have come full circle, right back to where I started the previous thread. Everybody is up to date, and now that the back story is filled in, I am hoping that this will be helpful to everybody concerned.

(edit to add) Maybe now my original thread will make more sense if you read the OP:
http://castboolits.gunloads.com/show...stency-applied

Thank you.