How consistent are you REALY???

[cbrick]

Do the same test at 700--725 & see if you get similar voids.

Merry Christmas . . .

Rick

[cbrick]

Also add 2% Sn.

Rick

[MBTcustom]

I'm not getting "voids". I got a void in a boolit, and think popper was asking about that, so I investigated.
I had noticed some uncharacteristically light boolits when I was casting with a 10 second pause, but I never looked into it further.
I think I'll boost the melt temp to 800* and see if it's more consistent than casting at 700*-725*. I suspect that like anything else, there will be an ideal casting temperature.
I used to think that most of shooting and reloading boiled down to "stay on this side of the line" but the further I go along, I see that it's much more about staying inside the line"s". There's lots of things that will work but there's usually a "sweet spot" in anything I do.
You know, launching a rocket to the moon is only possible if you get all the "sweet spots" lined up at once. Making a car that lasts 10 years is about getting all the "sweet spots" moving together.

[country gent]

First Merry Christmas to all a Happy birthday to Goodsteel and a thank-you for your time spent measuring charting and sorting this out. I have found several things over the years that contribute to consistency all around. First the bigger pots have slower smaller heat variations as it takes more to vary 100 lbs of mass than 20 lbs mass. Molds all seem to want thier own way of being ran, Filling the mold cooling the mold and such all matter. I use a 100lb pot for casting with a weed burner and heat shield around the pot / burner. Nothing fancy there I do have a thermometer in the mix that I check fairly often at a glance. about every 100 pours or so I lightly flux the pot. I ladle pour with a modified rcbs ladle, the spout has been opened up to just over .200 dia. My sprue plates are all vented now. I cast slower than most but also am more concerned with quality than quanity. The vented sprues allow for a full ladle to be poured and a consistent sprue to be maintained allowing for the base to be kept molten for longer allowing voids to work out better. I also have several nose pour that seem to cast better than base pours do. One is a lymann 535 grn postell that I cast with before it was converted and after being converted to nose pour and vented. Bases come out much better and weights are more consistent after being converted to nose pour. Pace fill time and temps all have a direct effect. I suspect the added base plate heavier sprue plate spacer rod all added mass to the mold and thus cosistency to its holding temperature. I also have a brooks nose pour adjustable cup based that is the same as the postell mold I converted. I dont pour to a sprue I pour a full ladle thru te mold and allow the extra to vent of keeping everything hot as long as possible. I pour with the mold over the pot helping to hold maintain heat also. After the mold is filled it is moved over the sprue container and about 8-10 sec allowed for sprue and bullet to cool. Sprue is then cut and base inspected vissually. mold is opened and bullet dropped out on a towel. Mold is closed by hand and sprue closed with small soft faced hammer. I then give 3 light taps on mould handles at the block pin area to ensure its fully closed / seated/ Back over pot and raise ladle out of lead make a small pour thru nozzle and fill mold again pouring the full ladle thru. I get very consistent bullets this way.
Another thing to remember is a 1% variation on a bullets wieght is variable due to wieght 1% of 500 grns is 5 grns 1% of a 180 grn is 1.8 grns and a 55grn is .55 grn. All 1% variation but a big diffrence in actual wieght there. A 1/2 grn variation on a 550 grn bullet is actually .1% . Something to think about and maybe give a little added pespective. On these big bullets 2 grns is actually .5% varience. I am interested in this thread and following it closely. I wonder if spinning at high rpms would show Balance and voids cosistency better than wieght.

[MBTcustom]

Country Gent, Thanks for the information! Very well written, and easy to visualize.
I'm thinking I may not fully understand some of the terms you use. Especially the part about venting the sprue plate. I have broken the edge of my molds to make a single vent line right down the middle of the mold, but I get the feeling you are talking about something a little more aggressive than that, yes?

Have you ever done a graph like I have shown here? I'm actually shocked that I am getting as good results as I have posted. Some of my old molds have been rode hard and put up wet so many times, I don't think they will hang with these new high quality ones from Accurate, Mi-heck, NOE, and such. I busted out a few of the old ones, and tried this a while ago, and it was rather dismal.

[dverna]

Goodsteel

There is a sweet spot and sweet area. In the process industry we try to determine a set of parameters that permits a wide "process window". That means that we can produce a good product within a relatively wide (but controllable) variation in the process parameters. For example, an alloy that casts well within range of +/- 25 degrees is better than one that works well with a temperature range of +/- 10 degrees. Similarly, an alloy and/or mold that produces good bullets with a mold temperature that varies +/- 25 degrees is preferred to one that gives superior results at +/- 5 degrees because holding +/- 5 degrees is too "tight" a process window and difficult too maintain. (We all have molds that seem to produce good bullets almost every time - and others that are "picky" - why???).

This is one reason PID controllers have a benefit for the casting process. They allow at least one parameter (alloy temp) to be controlled and held relatively constant.

With a bottom pour pot, we use guides (or should) to maintain the same distance from the spout to the sprue. We also should attempt to maintain the level in the pot consistent as possible - but the nature of the process makes this nearly impossible unless we have a secondary pot to "top off" the primary pot. It could be one reason why some people get better results with a good consistent ladle technique. They reduce the "head" variation between pours.

The "cadence" spoken of affects mold temperature. Mold temperature (and how much of "puddle" we use) will affect shrinkage and weight. One of the reasons I believe the old 10 cavity H&G mold was such a great mold was the trough they used to maintain a good supply of melt over the cooling bullets - but that is supposition on my part.

This may get some push back - but it is impossible to cut every cavity in a multi-cavity mold the same way. "Good" molds will have less variation per cavity than "poor" molds but all of them will have some variation. Again, reducing variation will result in more consistency. Common sense tells us a single cavity mold will be more consistent than a four cavity mold. But unless we are looking for that last 1/4 MOA (or whatever it works out to be), that consistency may have negligible practical value - but it is still there.

I really like the work you are doing and your willingness to share what you are discovering. Many will learn from your work.

Don Verna

[MBTcustom]

Hell, I'm doing it anyway, why not post about it? LOL!

[Doc Highwall]

About the technique we use and how we picture things in our mind and then explain those techniques to other people might not be reality. This was learned a long time ago when I belonged to a bass fishing club and at a meeting we were talking about our techniques. One of the members mentioned that what he had learned watching another member that was good, was how this member was reeling in the lure and the fact that this person did not even realize something that he was doing while reeling so when he explained his technique it was left out. In other words through the eyes of a care full observer what he thought he was doing and explaining about his technique in reality was just slightly different but was actually important.

I know about the quest for knowledge and what can happen when you ask yourself “What if” and the roads that it will lead you down. I am not afraid to share my knowledge with others and like someone here has as their byline “Ask me how I know” when we mostly share our knowledge about something that does not work.

[Larry Gibson]

Do the same test at 700--725 & see if you get similar voids.

Merry Christmas . . .

Rick

+1

Larry Gibson

[357maximum]

When you get done with this test you will have to investigate why you get more consistent boolits when you are hopped up on caffeine and your hands are shaky.....oh wait maybe I should do that one. .....actually I sit my mould in front of a high speed fan that imparts some subtle vibration to the table while the sprue sets and as long as I sit the mould on the clay floor tile sitting in front of the fan everytime all is good. If I happen to NOT sit the mould down on the clay tile while the sprue is "galvanizing over" the boolit will almost always come out a 1/2 grain lighter. There is some good to be had from consistent vibration....I think that motion/vibration is why Dillon progressive powder measures are so accurate too, but have never investigated the phenomena.

All the little consistent inconsistencies add up.....looking at your boolit graph you are doing something subtly different on some of the casts......pot intricacy/cadence/tempo/galvanizing time/cooling time all need to be as close to the same as we humans can get them.......to be dead honest you are getting better more consistent results than I ever did with a casting pot with a hole in the bottom of it. I simply did not make a good bottom sucker apparently.

Merry Christmas

[Larry Gibson]

Attachment 91555

Also add 2% Sn.

Rick

+1. Add the 2% tin to the COWWs before mixing with the lead or add 1% to the 50/50 mix. I do appreciate all the work goodsteel is putting into this, probably good for many newcomers to cast to see what casting inconsistencies and an improper blend of alloy for the temp cast at can get you in the way of inconsistent bullet weights. Too often we see advise to use "50/50 and cast at 650" w/o understanding what really is happening or not happening to the quality of the cast bullets. Many of us have already gone through this "experimentation" many years ago and probably repeated it several times in the interim. The advice is posted in this thread on what to do to correct the problems goodsteel is kind enough to demonstrate. Excellent thread goodsteel

[Jim Flinchbaugh]

[COLOR="#800080"] I sit my mould in front of a high speed fan that imparts some subtle vibration to the table while the sprue sets and as long as I sit the mould on the clay floor tile sitting in front of the fan everytime all is good.

I've given this some thought before, & I have a vibrator out of old hospital bed I've thought about screwing
to the underside of my casting bench for this very reason. I just might have to try it now

[popper]

Thanks Tim. Please check the inside of the rest and find the other voids. Now we know what to avoid in getting excellent boolits. I've broken a bunch in half and not found any void but now I know how big they can get. Btroj started a thread about swaging these to get better boolits but thinking about it, how could you get the air out of a solid. I remember a Trumph gear box full of cast gears that had lots of voids, and they always broke at the voids.

[felix]

I am interested in this thread and following it closely. I wonder if spinning at high rpms would show Balance and voids consistency better than weight.

Yes, indeed! I have been behind that solution from the beginning of my boolit shooting. The person who I asked to make the device for me said I could shoot BR bullets for the rest of my life for the same cost of building it back then. Well, it could be much cheaper now, especially if I did the programming of the electronics for him. Anyway you look at it, it is far cheaper to shoot larger targets and learn to be just as satisfied. ... felix

P.S. The same person did do a couple of triggers for me. I thought I could shoot better with ball bearings being used as "sears". He modified stock Remington triggers (1960's model) into various configurations for me to test in his office as applied to my bench gun. They had to be a legal configuration, so no electronics. Long story short, they were far too sensitive for me, even though they were adjusted to eliminate specific stepwise complaints. The fact dealt with what I could get used to on the firing line. Answer: None. ... felix

[country gent]

Tim the vented sprue plate is basically a groove of about 1/8" radious to the side of the plate from the sprue hole that allows lead to "flow" controlled off the side of the mold allowing the bullet to be kept molten much longer. Look at Brooks molds it may show on his site. I have wieghed my bullets from sessions to sort for voids that may occur other than the oddballs like you are showing I am normally about a 2 grn spread on 500-550 grn bullets I sort by wieght and shoot in .5 grn batches. I have tried weighing and shooting from light to heavy in .1 grn increments and seen no real improvement in group sizes. I normally cast from 20-1 alloy so flow is improved with that alloy also. I have a malcomn scope to be mountedon the BPCR rifles so maybe testing again will show somethingdiffrent with it, my eyes arnt what they used to be before the MS. I beleive a balance test at close to the rpms of the bullet in flight would show alot. There used to be a gage / tool that sorted for consistency called a Juneke gage ( I believe) that sorted jackets by concintrecity with an electric resistence, It might show voids also. Had a friend that had access to one and for awhile he sorted 168 sierra matchkings for 600 yds out to 1000. Not sure if it made a big diffrence or not. In all honesty you can spend alot of time energy and money sorting and possibly not see a diffrence. I sorted for awhile on a 100x comparator checking ogive and boattail forms. As we have known bases are critical area and a void offcenter will definitly cause balance ( yaw) issues with a bullet. I havent really figured a good way to safely spin a bullet between cup points at the rpms need to show the vibration ( balance) issues.
Alloys make a diffrence in consistency also alot of alumnium, zinc, mish metal alloys are injected under pressure to get the strength fill out of parts in industry settings, ( I worked as a tool and die maker in the auto industry our plant ad a die cast area and while nott involved with it I spent alot of time talking with the diecast die makers learning). Casting temps can be critical, mould temps are critical, fill temps and pressure are important. Some of our cold poured plastic / poly urethane parts were poured and held in a vacum to pull air out also. At times vibration was also used to work air out and improve fill. At the plant there were 3 50,000 lb furnaces for aluminum this was then transfered to the casting machines where temps were also maintained.

[MBTcustom]

Country Gent, I know all too well what you struggle with when you talk about MS. My wife has that disease as well. Casting and boolitry is what helps keep me sane.

Thanks all you fellers for the info. I'm not discounting anything that has been posted.
Several have mentioned that I should add tin to the mix. I am intentionally not doing that. I carefully control all my alloys, and nothing goes into my pot that I don't know within .1% what is in it. I have the ability to make whatever I care to use. In this case, I emptied out a pot of metal that was 94.6 % lead, 2.1% tin, and 3.3% antimony in order to make this pot of 50/50 metal (which is about .5% tin and 1.4% antimony in case anybody is interested).
Yeah, I have had every single batch of lead in my stash XRF tested. Was that overboard? (and all across the country, booliteer's heads exploded). LOL!

[dtknowles]

Hell, I'm doing it anyway, why not post about it? LOL!

I weighed the rest of a batch of 22 bullets I cast most recently, a few hundred of them are already loaded in .22 Hornet ahead of a light load of Green Dot to be used as .22 RF replacement ammo. I have shot maybe 40 of them already that I loaded to two different overall lengths. The shorter ones shot better so that is how I loaded the few hundred I put on the shelf.
Attachment 91579
I will toss the low weight ones. Clearly not a bell curve but a strong peak around 43.7 / 43.8 gr.

There might have been some low weight bullets in the ones I tested and on my shelf but the load tested was acceptable to me, IIRC they shot under a inch at 50 yards for 5 shot groups from my Ruger #3. These were loaded unsized (dropped .226 to .227), pan lubed 50/50, in unsized brass. The bullets are probably harder than need be as I cast them from my approximation of Lyman #2 (mixture of range scrap, monotype and Tin solder) I used a Lee 5# bottom pour pot that most times drips and for this mold I poured on the edge of the sprue hole/plate not right in the hole and leave a large sprue. It is a three cavity mold.

Tim

[MBTcustom]

That is an excellent curve there Tim. Just cause it's not curvy, doesn't mean it's not a curve ya know?

I ran one more batch myself tonight. This time I ran the pot at 790*. I kept the same cadence that I used previously, and I made some interesting observations.
1. Contrary to what I would have thought, I experienced much worse base fillout with the hotter alloy than with the cooler alloy.
2. Contrary to what I would have thought, the boolits were shinier on the noses and I even got a few ventline whiskers.
3. Contrary to what I would have thought, the target weight of 173.3 grains did not change with the higher temperature! Only the variances did! Through all of the tests, 173.3 has always emerged as the clear winner in the lineup with that particular weight running the longest line of boolits on the paper. All I succeeded in doing by monkeying with the temperature was to cause the base of the Christmas tree to swing it's hips left or right. I can effect the variances and the spread of them, but the tip of the curve is constant within .1 grains. Am I the only one who finds that just a teeny weeny bit fascinating!?!?!?
It seems that the only way I can effect the target weight of the mold is with alloy. Temperature may throw me a bunch of curves, and spread the base of the bell from one end of the page to the other, but only alloy can shift the point of that stack even .1gr up or down.

I'm not done with this test by a long shot. This is good stuff!

Oh, BTW, Here's the lineup:
Attachment 91585

[waksupi]

Just to let people know, Joe's input in any way, shape or form are not to be posted here. There is a reason he was banned from here twice, and will not be allowed to cause trouble from afar.

[MBTcustom]

Just to let people know, Joe's input in any way, shape or form are not to be posted here. There is a reason he was banned from here twice, and will not be allowed to cause trouble from afar.

That includes inflammatory references to him. When a member is banned, they are out. Taking cheap shots at a banned member is as inflammatory as posting their comments for them. Neither will be tolerated.