What Temps do you cast your varieties of bullets at?

[blasternank]

I've been reading a great deal on this forum. Great info! Everyone says you need consistency to get the best casts. I've seen people say that for big boolits less temperature is best and for small boolits it's best to be hotter. I've also seen people say never heat your lead up more than 750 degrees and others say they go hotter than that. My question is simple.

What temperature do you use to cast your various bullets?

Right now I'm going to cast a .510" bullet plus 9mm, 38/357, 45 acp and probably 44 mag. But I would like to see what you use for a variety of bullets as in the future I may be casting for them as well. If you have a reason why you use a certain temperate or pro's or cons of certain temps with certain rifle/pistol casts I'd love to hear about them.

Thanks.

[454PB]

There are too may variables to give you a solid answer. The alloy, boolit size and weight, mould design (steel, aluminum, brass) and number of cavities are just some of the factors involved.

That said, I tend to cast hotter than most members on this forum. 650 degrees is about minimum and 750 is where I usually end up. I didn't even have a lead thermometer until about 3 years ago, and adjusted temperature by the resulting boolits. To me, the end result is more important than a reading on the thermometer.

[peerlesscowboy]

The rheostat stuck and the plastic knob broke on my ol' Lyman 10 lb bottom pour many years ago so I pretty much just run the same heat for everything. I sometimes adjust the valve for slower/faster and fine tune by the appearance of the bullets :mrgreen: Kind'a crude I guess but hey........it's more sophisticated than sitting out over the campfire at night casting bullets for the next days buffalo hunt?

John C. Saubak

[geargnasher]

Like 454 said, there is no way to give you an accurate answer that will work for you in every situation.

I notice that you do not specify WHICH temperature. That may be because you don't know that there are three temperature variables in casting, and they are all crucial to getting good results. Here's the way I see it:

ALLOY TEMPERATURE/POT TEMPERATURE: This is the one that everyone fights and argues about, because there is so little understanding of metallurgy among most boolit casters, and other factors that I'll get into in a minute cloud the issue of pot temp and make folks come to the wrong conclusions.

One of the great enemies of the boolit caster is oxidation. Oxide scum, or "dross", forms on top of molten boolit metal anywhere it is exposed to oxygen, like at the surface of the pot and on the surface of the stream as it's being poured into a mould. To protect against the flash oxidation of lead and antimony, tin is added in small quantity to create a moving oxide barrier on the melt's surface, thus allowing it to flow better and fill out our moulds. The issue with temperature arises because the oxidation rate of tin accelerates rapidly with rise in temp from anything above fully molten. A typical boolit casting alloy contains mostly lead, a few percent antimony and one or two percent tin, unless using a "type" metal alloy, Lyman #2 or such. These types of alloys are molten, or at full liquidus, at anywhere from 475F to 600F depending on composition. For most casting purposes, I've found that anywhere from 75 to 125 degrees above full liquidus is all that's needed, or wanted, for casting. Take, for example, typical clip-on wheel weight alloy with one percent tin added. This will melt at about 560-570F, and starts to cast really well at about 650. I watch the melt temp and usually run it to about 675F or so during the casting sesson. OK, heres why: At temperatures approaching 750F with this type of alloy, the tin begins to oxidize at an astronomical rate, creating a thick dross layer and gradually depleting the tin from the alloy. Antimony oxidizes out, also. This is not gravity segregation, it's oxide segregation because tin and antimony oxidize at a different rate from lead. Overheated alloys also have issues filling the moulds because the tin oxide protective surface film on the poured stream is rendered ineffective by the higher temperatures, and the total tin content of the alloy is getting less and less as the tin forms oxides at the top of the pot. Once the tin is oxidized out, the alloy still won't cast as well at reduced temperatures unless the tin oxides are chemically "reduced" back into the melt using hyrocarbon sarificial recucants (candle wax, sawdust, etc.) The higher the tin percentage, the lower the melt point of the alloy (to a point) and the lower the pot temperature needs to be. I feel it is important to recognize that, in principle, alloy temperatures should be maintained in the casting pot at a point that is best for the alloy composition you're using. Usually that's 650-725 for most WW material, Hardball, and Taracorp Magnum, a little lower for Lyman #2 and lower still for pure Linotype, 20:1, 16:1 and such. For 40:1, pure lead, or very mild alloys around bhn 6-8, a higher pot temperature is desired to get good mould fillout, and oxidation of tin, since there isn't much present, is much less of a concern. These low-tin alloys can be run over 900F with no ill effects if that is what the mould design needs to fill out.

MOULD TEMPERATURE: This is where many peope get confused. They shouldn't, it's simple. Your mould blocks need to be a certain temperature in order to cast good boolits with nice, sharp edges, full fillout, square, clean bases, and consistent weight. The temperature a given mould likes varies on mass, block material type (coefficent of heat varies greatly between types of brass, aluminum, steel, and iron alloys), cavity mass/block mass proportion, ambient temperature, and boolit design. The important thing to remember is that mould temperature is king. Too many focus on pot temperature when they should be focusing on the mould, since the mould is what affects the initial flow and cooling rate of the alloy in boolit form. Most newbies don't realize how important a hot mould is, and will make one pour every minute or two and wonder why they can't get rid of the wrinkles in their boolits. Often it takes a good preheat of the moulds and 20 or more pours to get the blocks and sprue plate up to a good casting temperature, and then two to four pours per minute to maintain that temperature once it's reached.

Here are some temperatures that work for me, I present this as an example, your and other's milage will vary considerably based on your unique circumstances and appearance preference for boolits: Lyman two cavity mould, light boolit: about 325-350F, large cavity, heavy boolit, the same, but much slower casting pace to keep same temp. Lee two cavity moulds seem to like anywhere from 350 to 425F depending on boolit design, I have the best luck running them as hot as possible, meaning I cast as fast as I comfortably can with an alloy only about 75F over liquidus and never overheat the mould. Brass blocks seem to like a slightly hotter alloy in addition to casting fast for slightly frosted boolits (with WW alloy), I usually run these at about 380-400 with alloy about 100-125F over liquidus, this is because brass loses heat so fast you have to really keep pumping it into the blocks to keep them up to temperature, and a slightly hotter pot will help. Now, there's a good point that I mentioned I'd explain above: Many casters try to compensate for a mold that's too cool by cranking up the alloy temperature, and when that overheated alloy finally imparts enough heat to the mould to make decent boolits at their snail's pace of casting, they wrongly conclude that they must run their wheel weight alloy at 800-900F to get good boolits. What the should have done, but often don't know to do due to all the misinformation running rampant, is cast faster to get the mould hotter with the alloy still cool enough to be happy sitting in the pot for hours without burning out all the valuble tin. I've caught a lot of flak here and elsewhere for continually repeating these facts of alloy vs. mould temperature, but the physical propeties of metals are what they are, not something I make up. If you don't believe me, go reference the casting section in Lyman Cast Bullet Manual #3, as well as any edition of The Metals Handbook, it's all in there, and if you follow this you'll find I'm not wrong.

AMBIENT AIR TEMPERATURE: This one, along with humidity, affects our boolit quality considerably as well as alloy and mould temperature. Each Winter I see various "cold weather" casting techniques posted, and certain measures have to be taken to still get good boolits in a zero-humidity, freezing atmosphere. Same goes for casting in 90% humidity in an evaporating atmosphere near sea level on a 100 degree day. This is where each caster has to put it all together, experiement, and learn what works best for them on any given day. The important thing for every caster is to have a basic understanding of the variables with which they are dealing, how each affects the other, and how to sort it all out quickly and maintain consistency through a long casting session.

Hope this helps,

Gear

[Walter Laich]

I cast all of mine around 725*

Right now I'm pretty much only casting .45 Colt and .45-70 bullets

[gray wolf]

I have to agree, it's a hard question if you want a fine tuned answer.
Like asking whats a good load for my rifle.
Whats right for you depends on,
your metal, your casting speed, mold size, and a few other things. Like has been said, we can get a person started but the fine tuning comes from the person doing the casting,and knowing what to look for. Some learning needs to be done, tricky at first ---but not impossible.

[Charlie Two Tracks]

I am by no means an experienced caster but I have found out that it is the mold temperature and not so much the lead temperature that makes a difference. I keep my lead at 700 degrees most always. The boolits can vary in size by how hot or cold it is. That's what seems to be working for me now.

edit: dang! you guys got all that out while I was typing this. I have to get better at typing!

[XWrench3]

everything i cast is run at 750 defrees, plus or mius as little as i can get it. if it gets over 800, i either stop and let it cool off, or add more metal. 50 degrees below that, and things just done fill out well.

[FAsmus]

Gentlemen;

I've never used a alloy thermometer for the 30-some years I've been casting bullets.

There are enough variables to contend with that concentration on any one factor isn't going to do you much good.

I find myself running alloy very hot at times to improve its flow - hot enough that the top of the melt turns black as the slag oxidizes. At other times I run cool enough that the pot pretty much needs little or no attention besides clearing an area to dip the ladle each pass until it runs empty.

Different molds will at times be quite challenging to work with - patience is the only way to work these things out - pressure feeding the cavity, Wosika swirl from 1/2 inch above the fill-hole, various bottom-dump pots lend their own problems and solutions.

All-in-all I prefer to cast at around 40 degrees. This is cool enough that my furnace does not overheat me and warm enough that me feet don't get cold.

Good afternoon,
Forrest

[357shooter]

For soft alloy in 38/357, hot works well. I normally cast with 98% lead and 2% solder, with 150 - 200 grain moulds, they like 900 - 975 degrees.

The mould temp is pretty important too, just posted some test results & graphs in another thread. Again, with the soft alloy and with a 168 grain bullet (358-429) it likes the mould hot at (measure in the mould block w/the NOE thermometer) 530 degrees. That's 450 in the cavity when heated on a hot-plate or dipping it into the alloy.

Wheel weights take less heat, harder alloys work well with even less heat.

[44man]

All of my harder alloys from WW's up, I just set the Lee pot at 750. For soft I go to 800 or just above. I don't use a thermometer unless I am making an alloy in my smelting pot.
Boolits are controlled from casting tempo and too many years of experience to admit from this old guy! :bigsmyl2: I don't even need to pay any attention and if you watched me with my slow and easy casting, you would just go home shaking your head. It makes no difference between a 100 gr or a 560 gr boolit, all gets automatic with experience.
Most casting problems are caused by frantic, need to rush thinking. Preparation and mold temp is first, then when you can dump a 20# pot without a single reject, you are there.
Leave the dial alone, you are the control! [smilie=p:

[songdog53]

I try to cast between 700 and 800 because i have found i get frosty boolits quick after getting over that temp. Course mold heat has to be figured into that but I think is something is no set rule on, because each one uses different mixtures of lead and different molds. I found i had to fine my own sweet spot and remember which boolits likes. I poured a bunch of 44 caliber that weighs 255 and their sweet spot was like 725 but 225gr 45's like it wee bit hotter and have to watch or mold heat.

[white eagle]

what Jim said

[357shooter]

Who's Jim?

[dragonrider]

I cast with only straight WW's at 800 to 850. Fillout is normaly good, on those occaisions when it isn's I find I am casting too slow or spending too much time on the wet rag.

[rintinglen]

I run with Gear on this one. It can hardly be said better. His metallurgy explanation ought to be a sticky some where.
There is one other element that comes into play and that is the temperature control element on your pot. My old 10 lb lee would cycle nearly ,20 degrees, by itself. Your metal casting temperature should be high enough so that the low point doesn't get you in trouble.
However, I find that for me, I have to run hotter--700-750--with non-ferrous molds to get good boolits, and when I'm casting big boolits for my 45-70 from iron or steel, The dial goes way down. I have a four cavity 457-192 that goes from cold wrinkled to good in about four casts, and then gets so hot in four more casts that the sprue takes 30 seconds to fully freeze. The temperature has to go way down for that one to make good boolits. At least, to make them at an reasonably fast rate. On the other hand, I recently bought an NEI aluminum 4 banger 32-100 that I can't cast fast enough to get good boolits out of it. Aluminum and copper are extremely good conductors and don't hold the heat as well as an iron mold will. Often times with a mid to light weight lee 6 banger, the first four boolits drop perfectly, but the last one or two show wrinkles because the mold has cooled enough at the end to freeze the metal before you get good fiil out.
There is a lot of science involved in boolit casting, if you care to make it so, but I cast half a ton of 38 wadcutters back when I didn't know squat, and can only wish that I could still shoot as well as I did back in the disco days--sigh.

[44man]

I run with Gear on this one. It can hardly be said better. His metallurgy explanation ought to be a sticky some where.
There is one other element that comes into play and that is the temperature control element on your pot. My old 10 lb lee would cycle nearly ,20 degrees, by itself. Your metal casting temperature should be high enough so that the low point doesn't get you in trouble.
However, I find that for me, I have to run hotter--700-750--with non-ferrous molds to get good boolits, and when I'm casting big boolits for my 45-70 from iron or steel, The dial goes way down. I have a four cavity 457-192 that goes from cold wrinkled to good in about four casts, and then gets so hot in four more casts that the sprue takes 30 seconds to fully freeze. The temperature has to go way down for that one to make good boolits. At least, to make them at an reasonably fast rate. On the other hand, I recently bought an NEI aluminum 4 banger 32-100 that I can't cast fast enough to get good boolits out of it. Aluminum and copper are extremely good conductors and don't hold the heat as well as an iron mold will. Often times with a mid to light weight lee 6 banger, the first four boolits drop perfectly, but the last one or two show wrinkles because the mold has cooled enough at the end to freeze the metal before you get good fiil out.
There is a lot of science involved in boolit casting, if you care to make it so, but I cast half a ton of 38 wadcutters back when I didn't know squat, and can only wish that I could still shoot as well as I did back in the disco days--sigh.
This is NOT how casting should go. Nothing should ever change at any time.
The biggest problem is PRODUCTION and some of you would try a 20 cavity mold. We are not foundry owners, we have simple tools.

[white eagle]

Who's Jim?
[smilie=l:

[geargnasher]

I try to cast between 700 and 800 because i have found i get frosty boolits quick after getting over that temp. Course mold heat has to be figured into that but I think is something is no set rule on, because each one uses different mixtures of lead and different molds. I found i had to fine my own sweet spot and remember which boolits likes. I poured a bunch of 44 caliber that weighs 255 and their sweet spot was like 725 but 225gr 45's like it wee bit hotter and have to watch or mold heat.

Frosty boolits are a function of MOULD TEMPERATURE, not alloy temperature.

I can show you how to cast boolits that look like a hot-dipped galvanized nail from wheel weight alloy at 625F, and I can also show you how to cast shiny boolits with 850F alloy.

The difference is how hot the mould blocks are. This factor IS a "set rule" universal among antimonial alloys, it is not a unique function of an individual mould. Regardless of alloy temp, whether the boolits are frosty or not depends on how hot the mold is, period.

Gear

[HammerMTB]

Most of my casting is at 725F, using WW or some WW with an adder that benefits my purpose for the boolit.
I find it somewhat easier to bump up to 750F or slightly higher if I am casting pure Pb, which isn't often. Most of that is due to mold temp, and wanting a hotter melt to carry more heat into the mold.
One day I may have to find out what it will take to pour zinc boolits, or maybe we should rename them zoolits. [smilie=1:

[warf73]

Most my casting temp is a range of 725~850* depends on what I'm using aka alloy, size of mold, mold material.

[htower099]

IM USING {used} a lee 10 pound bottom pour pot.. i set 4 ingots on the pots open top to pre heat. while the lead comes to temp, im also using my colman propane stove to pre heat the molds..a bucket w/ about 4 gallon of water sets between my feet.

aluminum lee molds heat faster than cast iron molds..be advised to time the heat differently..

the poor. my operation was low budget.no thermometer... if the molds made wrinkled bullets its mold is too cool/ or lead is not hot enough, for the glass and water debate folks..wrinkled or not filled out and the lead or the mold wasnt hot enough.. i check the first few from every mold.. i run 3 molds at a time..if temp is low i set the mold onto the camp stove.. letting the lead warm up at the same time...

too hot...an extremely too hot bullet will crumble easily w/ pliers. it will have a look of galvanized steel also..that galvanised look is cooler than a crumbling product.. but either or, its too hot...

ok, the pour.. all the bullets are filled out.. especially looking at the round border on a SWC bullet.. if its rounder its not "filling out" the mold.. more heat..also let the lead visible cool, you can see the spur change color when it sets up.. this will let the lid/spur cutter CUT insted of ripping the spur.. and look of bottom of the bullets w/ holes.. not good. if you let the lead hit the bevel on the spur it will give the pour a swirl. this also helps molds to fill out better..

be sure to stir the pot as often as once per round of molds pour..tin, antimony, all the good stuff in wheel weights desire to seperate w/ heat.. tin is hard to see unless the pot becomes too hot.. at that point you have colors like blue and yellow floating.. on top of the pot.. you got too much heat and didnt stirr much..the tin in wheel weights are what make them desireable for casting so keep stirring. this helps keep bullets consistant from one to the next when the metal is evenly mixed..

i also add a pre-heated ingot as soon as ther is room for it..
running 3 molds at once, one being a 4 cavity 44 mag mold and a double cavity 45 acp and a two holer in 40 sw you can drain half a pot in 4-6 passes.... better to add lead asap and try to keep the heat up.. normally i would cast the pot and 30 ingots before i ran out of heat.. the pot just couldnt keep up, even w/ a 4 ingot preheat to start w/..


pre-heat ingots.. i laid the ingots on top of the pots opening trying to close it up. leaving enough room to function the pour lever.. adding 2 from the left first then re-setting 2 new ingots.. this lets the 2 on the right to heat up longer and not steal away as much heat when added to the pot.. then add the 2 from the right side.. e.i.e.i.o. untill the heat runs out. basically you want the ingots you add to the pot to be as warm as the pot is, or, as close to as warm as possible, this way the pots temp doesnt fall too low ads new lead ingots are added..

by this time you are ready for a break ..set everything up to pre-heat or stay hot.. while you fish out the wire basket from the bottom of a 5 gallon bucket {4 gallons of water}

these wet bullet go to a towel to dry and start seperating by caliber..while awaiting the pot to catch heat wise...

a normal cession would be about 90 minutes and result in 2500 bullets to sort later that night ..
sizeing and lubing when ever you get a day that able and away you go to boxem up for storage until reloading day..

special helpful notes... locally there was a specialty printer who still did lino type printing.. he gave me a 5 gallon bucket of "spent lino".. better yet he gave me the contact info where he bought his LINOTYPE HARDENER..

now its been 25 years, so, the place may not still be in buiz, but this may help give you an idea on how to, or, where to....chicago metals... it was a scrapyard. and sold industrial ingots.. iirc it was 6 3/4% tin and 11% antimony or visa versa..and the product is certified as pure percent wise.. called HI-TIN LINO..its used to harden linotype after 3-4 castings the metals seperat too much and the press run cant happen smoothly if all the letter B's fade out..so they add a hardener.. HI-TIN LINO, 50 POUND CAST INGOTS....

i made the "hi-tin linotype" into one pound ingots over a friends campfire in a hugh cast iron pot.. i them mixed these lino ingots w/ wheel weights. the ratio was 2 ww / lino ingot.. and ended up some where around 100 alloyed bars.. these all went to 30 cal and 44 can bullets...i swear the had a ring when you dropped one on the floor.. using a 173gr lfn 30-30 mold w/gc i had moa groups from a early 60s savage 308 riflr at 100 yrds. on a good day..

hopefully there are some new ideas here for you and rhis helps some of you.. likely its allready been posted, there hasnt been much change in the actual process, just force mulitpliers work wise that is .. do good htower099

back to temp topic.. sorry... i turn it up to 10 on thr reichter scale and fly thru the lead...i cast so fast and drop soo much volumn of material. my temp will drop in half a pot if i try to hold 800... by being on full burn and adding ingots as soon as they fit im dropping temp fast.. basically i use the visual appearance of the bullet as my guide.. ht

[geargnasher]

Just for the record, tin doesn't gravity-segregate from the other metals in the melt. In fact, tin binds with antimony to make the intermetallic compound Sb/Sn. Tin and antimony WILL exit the melt via oxidation at the top of the pot, and cannot be stirred back in unless chemically reduced back into elemental metals by reduction reaction with carbon and carbon monoxide. This is why to keep the melt under 750 degrees if there is a significant amount of tin present.

Alloys containing a percent or two of tin and a little antimony melting between 525-575 degrees) don't need to be run any hotter than about 700 anyway most of the time due to the lower melting point of the alloy. If using a softer alloy with little tin in it I've found it necessary to run the pot much hotter. But no matter, if the lead oxidizes on the surface it doesn't matter that much because it isn't depleting or changing the composition of the alloy.

Like has been said, if your boolits aren't filling out, get the MOULD hotter, not the alloy.

Gear

[44man]

Frosty boolits are a function of MOULD TEMPERATURE, not alloy temperature.

I can show you how to cast boolits that look like a hot-dipped galvanized nail from wheel weight alloy at 625F, and I can also show you how to cast shiny boolits with 850F alloy.

The difference is how hot the mould blocks are. This factor IS a "set rule" universal among antimonial alloys, it is not a unique function of an individual mould. Regardless of alloy temp, whether the boolits are frosty or not depends on how hot the mold is, period.

Gear
Exactly right!
I compare casting good boolits to using a single stage press when others use a huge Dillon to pound out loads.
A few want to cut molten sprues, others need wet rags, some cast so fast boolits vary all over the place.
I like two cavity molds and most of the time I use two at once and on some occasions I have run three but it is harder to get the third to temp without another mold oven and hot plate. Probably blow a breaker!
I made my mold blocks large, out of aircraft aluminum but I use all kinds of molds and find no problems using one of mine and a Lee, RCBS, Hoch, Rapine or Lyman, side by side.

[Bass Ackward]

Way to many variables from the mix to the humidity and temperature levels to single or multiple mold use. There is not a reliable enough pattern that I can see to make this worth tracking after I did it for years.

Pay attention to your equipment and the bullets it's producing and then produce good slugs when you hit the zone. If that turns out to be 650 or 900 is of no consequence to me because it is what it is.

I will then hold the temp that's working for me on that day and maintain the rhythm.

[zomby woof]

I've been running around 725.
After reading this I'm going to try under 700.

[AZ-Stew]

I've been running around 725.
After reading this I'm going to try under 700.

If your current alloy temp produces good boolits at the speed (pace, rhythm) you cast, there's no need to reduce temp. If you DO reduce temp, you'll have to cast faster to maintain mould temp. Nothing wrong with that, just be aware. Every action has a reaction.

Regards,

Stew

[geargnasher]

So you guys are right about the mould temp being very important. However hot alloy can and will heat a mould quicker. The pace and or cooling (if needed) has to be adjusted to.

So indirectly it causes frosting, hotter alloy heats the mould, hotter and faster and then the bullets are frosted. I believe that is the effect some folks are referring to when they say hot alloy causes frosting.

Is this point of view not valid? :bigsmyl2: :bigsmyl2:

The way you put it very much confuses the issue here. The more this topic is breached the more I learn how little the average caster knows about what he's working with. I'm attempting to clear up this very basic and very misunderstood topic.

Yes, the heat transferred by the lead to the mould causes the mould to warm up. If the operator is casting at a pace sufficient to get the mould up to "casting temperature", (whatever that may be, it's a HUGE variable here) and keep it there, he will get good boolits regardless of alloy temperature (assuming he's doing everything else right!), as long as the alloy is being maintained at a point that is best for the alloy itself. The mould temperature affects the boolit quality directly. Simply saying that alloy temperature makes a boolit frosty is really not an accurate or valid statement because it implies that an adjustment to pot temperature is needed to make a boolit frosty or shiny directly, when the only thing pot temperature can change is mould temperature, and mould temperature is the thing that affects the boolit.

Mould temperature controls boolit quality, regardless of alloy temperature. The big variable so many people seem to miss is CASTING PACE. If you're casting with a high-mass, brass mould with small cavities, you'll have to haul butt to keep the mould up to a good casting temperature with typical alloysl, and you'll probably need to push the envelope on pot temperature for that alloy to get as much heat in the mould as you can. If you're casting 500 grain boolits an iron mould you will likely need to do exactly the opposite, as the mould will quickly overheat. that means waiting up to 10-12 seconds between pours and running the pot as cool as you possibly can and still get good fillout.

Balancing the casting pace to the alloy, the thermal conductivity of the mould, the amount of BTUs put into the mould each pour, and the thermal conductivity of the air in the casting area (a function of temperature, humidity, and drafts) is how you get quality boolits, but you also need to maintain the pot temperature at a point that is best for the health of the alloy and adjust the other variables to get the boolit quality you are happy with.

Don't take my word for it, go throw some wheel weights in your casting pot, set a thermometer in there, run them up to 625 degrees and start casting like the devil with your favorite mould, from a cold start. Your boolits will be wrinkled and shiny at first, then pass through the ideal temp range for the mould until they start to frost at the edges, then lighly frost all over, then start to look dull and pitted, and finally begin to crumble as you dump them from the mould. Now, crank the pot up all the way, allow the mould to cool until you can hold your hand on it, and do it again casting as fast as you reasonably can. Guess what? Your results will be the same except the time it takes to overheat the mould will be less.

I don't know how many other ways there are to say it.

Gear

[geargnasher]

Exactly my point, Stew.

Gear

[357shooter]

The way you put it very much confuses the issue here. The more this topic is breached the more I learn how little the average caster knows about what he's working with. I'm attempting to clear up this very basic and very misunderstood topic.

Yes, the heat transferred by the lead to the mould causes the mould to warm up. If the operator is casting at a pace sufficient to get the mould up to "casting temperature", (whatever that may be, it's a HUGE variable here) and keep it there, he will get good boolits regardless of alloy temperature (assuming he's doing everything else right!), as long as the alloy is being maintained at a point that is best for the alloy itself. The mould temperature affects the boolit quality directly. Simply saying that alloy temperature makes a boolit frosty is really not an accurate or valid statement because it implies that an adjustment to pot temperature is needed to make a boolit frosty or shiny directly, when the only thing pot temperature can change is mould temperature, and mould temperature is the thing that affects the boolit.

Mould temperature controls boolit quality, regardless of alloy temperature. The big variable so many people seem to miss is CASTING PACE. If you're casting with a high-mass, brass mould with small cavities, you'll have to haul butt to keep the mould up to a good casting temperature with typical alloysl, and you'll probably need to push the envelope on pot temperature for that alloy to get as much heat in the mould as you can. If you're casting 500 grain boolits an iron mould you will likely need to do exactly the opposite, as the mould will quickly overheat. that means waiting up to 10-12 seconds between pours and running the pot as cool as you possibly can and still get good fillout.

Balancing the casting pace to the alloy, the thermal conductivity of the mould, the amount of BTUs put into the mould each pour, and the thermal conductivity of the air in the casting area (a function of temperature, humidity, and drafts) is how you get quality boolits, but you also need to maintain the pot temperature at a point that is best for the health of the alloy and adjust the other variables to get the boolit quality you are happy with.

Don't take my word for it, go throw some wheel weights in your casting pot, set a thermometer in there, run them up to 625 degrees and start casting like the devil with your favorite mould, from a cold start. Your boolits will be wrinkled and shiny at first, then pass through the ideal temp range for the mould until they start to frost at the edges, then lighly frost all over, then start to look dull and pitted, and finally begin to crumble as you dump them from the mould. Now, crank the pot up all the way, allow the mould to cool until you can hold your hand on it, and do it again casting as fast as you reasonably can. Guess what? Your results will be the same except the time it takes to overheat the mould will be less.

I don't know how many other ways there are to say it.

Gear

FYI, you must have caught that just right. I deleted the post as I didn't want to confuse the issue much more.

I'm a process centric person and always look to how tweaking one step makes a change in another step further down the line.

You have made the same point a few times so there's no real need to say it again. I do think that my point (although deleted, but still quoted) is valid. It's all about how the casting process works together to produce either great or not-so-great bullets.

I think you said the same thing I did, but sounded like we disagreed, not sure why I need to go try anything. You were responding to something other than my comment maybe. Also, I don't believe I confused anything, but instead explained why there is some validity to what people say.

[geargnasher]

357, I was responding in the context of a broader audience, those beginners who are trying to figure this hobby out, and have unfortunately been mis-advised to crank up the pot temperature rather than cast faster. I know that when I first started out I naturally assumed that lead poured into a cold mould ought to make good boolits, it never dawned on me that the mould temperature mattered at all. Then, fortunately for me, I had someone to explain it to me, and in person no less! Both hotter alloy and faster pace achieve the end result of making the mould hotter, which usually is better for fillout and quality boolits, but the subject of tin depletion from overheated alloy is often missed. Too many people have the wrong idea about what they're doing, you can tell by the constant stream of help requests regarding fillout, and too few people are offering the simple knowledge that can help them determine what adjustment to make for best results with their particular setup. I'm trying to help those people out, hopefully someone will read this who might have been having trouble with a mould and reading this will help.

Gear

[warf73]

Mould temperature controls boolit quality, regardless of alloy temperature. The big variable so many people seem to miss is CASTING PACE. If you're casting with a high-mass, brass mould with small cavities, you'll have to haul butt to keep the mould up to a good casting temperature with typical alloysl, and you'll probably need to push the envelope on pot temperature for that alloy to get as much heat in the mould as you can. If you're casting 500 grain boolits an iron mould you will likely need to do exactly the opposite, as the mould will quickly overheat. that means waiting up to 10-12 seconds between pours and running the pot as cool as you possibly can and still get good fillout.

Well said geargnasher

[lwknight]

We all want the very best boolit that we can produce and many , like myself want the most out of our time as well. The lowest casting temperature that works also yields the highest production rate as a by-product.
I think that is part of the " how low can we go " logic.

[357shooter]

357, I was responding in the context of a broader audience, those beginners who are trying to figure this hobby out, and have unfortunately been mis-advised to crank up the pot temperature rather than cast faster. I know that when I first started out I naturally assumed that lead poured into a cold mould ought to make good boolits, it never dawned on me that the mould temperature mattered at all. Then, fortunately for me, I had someone to explain it to me, and in person no less! Both hotter alloy and faster pace achieve the end result of making the mould hotter, which usually is better for fillout and quality boolits, but the subject of tin depletion from overheated alloy is often missed. Too many people have the wrong idea about what they're doing, you can tell by the constant stream of help requests regarding fillout, and too few people are offering the simple knowledge that can help them determine what adjustment to make for best results with their particular setup. I'm trying to help those people out, hopefully someone will read this who might have been having trouble with a mould and reading this will help.

Gear
Sounds good. thanks.

[357shooter]

We all want the very best boolit that we can produce and many , like myself want the most out of our time as well. The lowest casting temperature that works also yields the highest production rate as a by-product.
I think that is part of the " how low can we go " logic.

For me, the lowest temp does not yield the highest productions rate. That may be the case for others too.

This must be very dependent on how much hot lead (caliber, bullet weight, number of cavities) goes into the mould compared to the size or mass of the mould. Of course mould material is a major factor too.

[Bret4207]

Gear has pretty much covered it. The only thing I would add is that I see a lot of people trying to cast with multiple moulds, using hot plates to keep the mould warm, etc. IMO it's a waste of time trying to use 2 or more moulds, especially if they vary at all in what they want. I know some people say they do exactly the same pour with all their moulds. Well, maybe, but it doesn't work for me at all. I want the best boolits I can make, that means one mould, doing things the way it wants and paying attention to what's going on. If you need a hot plate to keep your mould warm then you need to cut out a mould and work one at a time. Perhaps there's a person who can make high quality boolits using multiple moulds at once, but I've tried it for over 15 years and I don't see how it can be done, especially with aluminum moulds.

[btroj]

I think explained this very well. There is a temperature window where a mould likes to do best.get out of that window and you do not get the best results. It is that simple. As Bass put it- it is what it is.
I also agree with Bret. I have never had good luck using 2 moulds at once.I prefer to stick with 1 mould and get the best I can out of it. I would rather cast with one mould first then Change to a different mound if I want 2 different bullets cast that day. This is a personal preference thing, not something with a right or wrong answer.

The top thing to get out of what gear said is the stuff about bullet size in relation to block size making a difference. I run small bullets in big blocks at a higher pot temp than most others because the mound needs it to keep hot enough. I run my 6 cav 45-70 much lower because that is where it works best. The mould determines the pot temp, it is not the other way around.

I do not use any thermometer in either the pot or the mould. I just keep a good eye on what works and what doesn't. If you learn to pay attention to your mould it makes this a much easier process. This is part of the art of bullet casting.

Bad

[44man]

Gear has pretty much covered it. The only thing I would add is that I see a lot of people trying to cast with multiple moulds, using hot plates to keep the mould warm, etc. IMO it's a waste of time trying to use 2 or more moulds, especially if they vary at all in what they want. I know some people say they do exactly the same pour with all their moulds. Well, maybe, but it doesn't work for me at all. I want the best boolits I can make, that means one mould, doing things the way it wants and paying attention to what's going on. If you need a hot plate to keep your mould warm then you need to cut out a mould and work one at a time. Perhaps there's a person who can make high quality boolits using multiple moulds at once, but I've tried it for over 15 years and I don't see how it can be done, especially with aluminum moulds.
NO, Bret, fill one mold and set it on a hunk of wood, pour the second mold and when the sprue sets, put it on the wood and go back to the first one.
The hot plate and oven is only used to bring the initial mold temp up for a good boolit. I use a setting of 500* for a first boolit's perfection.
Gear and Stew both have explained it very well indeed.
Using one mold only and you need to wait for good sprue setup but alternating molds will give perfect sprue setup while pouring the second mold.
Then some need a wet rag to speed setup but then you can screw up plate temps real easy and get rejects. Boolits can't pull lead from a cool plate that freezes the sprue.
Two cavity and single cavity molds are perfect for double mold use. Don't even think about it for a six cavity. You already have enough trouble! :takinWiz:

[geargnasher]

For me, the lowest temp does not yield the highest productions rate. That's because you're using an alloy that is much less sensitive to overheating than what most of us use, and you probably have to cast at a fast pace to keep your fillout good. You keep comparing apples to oranges, and since you're running without antimony and very little tin there are certain factors, like antimonial dentrite formation, that you don't have to contend with at all. You also run your moulds about 150 degrees hotter than needed for the majority of moulds using WW alloy. You don't have much of an issue with severe pitting and "sandblasted" appearance because there is no antimony in your alloy. With the alloy you use, you can virtually ignore overheating the mould or alloy, and let it get as hot as it will get. If you were using WW or any sort of tenary Pb/Sb/Sn alloy you would quickly discover that you will need to maintain your alloy and mould temperature much more closely, and for the quickest production rate with good fillout and minimal drossing, you'll need to run the alloy as cool as possible. When I use 30:1 I run my pot hot and let the mould get just as hot as it reasonably can, but there isn't any antimony to over-crystallize the surface. That may be the case for others too. For the few that use an alloy like yours, that is true.

This must be very dependent on how much hot lead (caliber, bullet weight, number of cavities) goes into the mould compared to the size or mass of the mould. Of course mould material is a major factor too. And the type of alloy. And the weather.

Again, I'm trying to put your statement in the context of the big picture here. You make a statement contradicting what so many of us have said about low pot temp/high production rate, but the rest of the story here is WHY your experience is different. All alloys have unique temperature requirements, and it's pretty easy to figure out what is best for each before you even turn the pot on provided you know a little bit about the properties of the particular metal you're using.

Here's the way I would tell a new caster to do it: After you figure out your approximate alloy composition, set the pot right in the middle of 100 degrees over liquidus and maintain it there. It will be very close to right, within 25 degrees to be sure. Whether the low end of that or the high end depends on the weather and the mould. Then start casting and fiddle with casting rate until the mould gets to the right temperature for your boolits to look the way you want them, and maintain that pace. Don't go fiddling with the pot temperature unless you change alloy composition.

Gear

[357shooter]

Again, I'm trying to put your statement in the context of the big picture here. You make a statement contradicting what so many of us have said about low pot temp/high production rate, but the rest of the story here is WHY your experience is different. All alloys have unique temperature requirements, and it's pretty easy to figure out what is best for each before you even turn the pot on provided you know a little bit about the properties of the particular metal you're using.

Here's the way I would tell a new caster to do it: After you figure out your approximate alloy composition, set the pot right in the middle of 100 degrees over liquidus and maintain it there. It will be very close to right, within 25 degrees to be sure. Whether the low end of that or the high end depends on the weather and the mould. Then start casting and fiddle with casting rate until the mould gets to the right temperature for your boolits to look the way you want them, and maintain that pace. Don't go fiddling with the pot temperature unless you change alloy composition.

Gear

I assume we are good and that you are messaging the broader forum and group of casters out there, as there nothing new in what you just said, or anything that is even in question.

However I can't type in all that stuff every time I post something. So I just say, for my alloy (98% lead and 2%solder), usually. Not every post, but a least once in a thread.

I'm guessing, actually I know, there are others out there that cast like I do. With alloys like I use. Providing them information is just as valid as anything you have had to say.

[casterofboolits]

Boy! A newbie could end up really confused with info overload and trying to incorporate the info into how he casts his boolits.

Like others have said, casting conditions, alloy, type of moulds, and lead pot are all contributing factors in geting good results and we all tend not to understand why others don't get the same results we do.

I keep my temp at approximatly 725-750 degrees and use that range for all my casting from 9mm to 45C. I prefer iron/steel mould blocks and only use a minimum of Lyman four cavities and almost always use three moulds in series and two RCBS 10 kilo pots. I rest my moulds between cycles on cast iron Lyman/Saeco one pound ingot molds turned bottom up. The ingot molds become heat sinks and help maintain mould temps. This worked for me with four cavity Lyman/Saeco, six cavity H&G, eight cavity Saeco, eight and ten cavity H&G.

I developed my casting methods when I had a hand cast boolit business for twenty three years. Having cast and sold several million boolits I'm kinda set in my ways. Also, I only do pistol boolits, the heaviest being a Lyman 45C-250-FPBB.

My advice is to experiment with alloy and temp and cast, cast, cast. But only change one factor at a time and keep detailed records of what you do.

[Bret4207]

NO, Bret, fill one mold and set it on a hunk of wood, pour the second mold and when the sprue sets, put it on the wood and go back to the first one.
The hot plate and oven is only used to bring the initial mold temp up for a good boolit. I use a setting of 500* for a first boolit's perfection.
Gear and Stew both have explained it very well indeed.
Using one mold only and you need to wait for good sprue setup but alternating molds will give perfect sprue setup while pouring the second mold.
Then some need a wet rag to speed setup but then you can screw up plate temps real easy and get rejects. Boolits can't pull lead from a cool plate that freezes the sprue.
Two cavity and single cavity molds are perfect for double mold use. Don't even think about it for a six cavity. You already have enough trouble! :takinWiz:

Sorry, but once again you have closed your mind. As I said, for a few people, maybe it works, just like you say you treat all your moulds exactly the same and never vary anything. Out here in reality-land that doesn't work. I've read numerous posts by people who simply can't keep a mould hot enough. Encouraging them to use multiple moulds instead of LEARNING what the mould wants just screws them up, just like vague recommendations about harder alloys, etc. We need to get people casting good boolits, not worshiping at someones ego altar.

[357shooter]

Casting sessions these days are the best (meaning the best bullets, and also the most enjoyable) when I put 10-12 lbs in my Lee pro - bottom pour pot. Let it come up temp, and give it an addition 20 minutes or so before fluxing.

Use one mould, usually a 2 cavity or 3-4 cavities of a 5-6 cavity mould, then cast the entire pot. A 110 Lee pot does pretty good with temps if you don't add anything to it. There's zero chance of freezing up the spout too, 100% guaranteed.

No adding of lead, varying of temps. If I switch moulds it's because I'm done with one and have the production I needed.
Added later: I do add hot sprues back in, but don't let them get very cool.

With 5 cavity moulds, I very hardle ever cast all 5 cavities. It seems to work out better and helps control the pace, temps, pour rate, alloy temp when casting with 2, 3 or 4 cavities (I cast for handguns, no rifles). This is a huge help to better control the pace, mould temp, cavity heating/cooling is more even and probably a few other good things happen. It does take a bit longer, but it makes the session more enjoyable and not quite to intense.

If there's more casting to be done, load up the pot, take a break while it all heats and do it again.

Works well, it's a slower pace. The number of rejects has gone down to almost zero and by there's less time load with bullets sticking and needing extra taps.

[44man]

Sorry, but once again you have closed your mind. As I said, for a few people, maybe it works, just like you say you treat all your moulds exactly the same and never vary anything. Out here in reality-land that doesn't work. I've read numerous posts by people who simply can't keep a mould hot enough. Encouraging them to use multiple moulds instead of LEARNING what the mould wants just screws them up, just like vague recommendations about harder alloys, etc. We need to get people casting good boolits, not worshiping at someones ego altar.
If you have seen my friends trying to do it as easy as I do and fail over and over even with me standing over them, maybe you would understand. It does take hands on help and it works with all of them casting perfect boolits now.
One will bring a mold over telling me it does not work so I take them to the garage and make a pile of perfect boolits, showing them how and they get it and go home happy.
You keep saying EGO, why don't you say EXPERIENCE?
Casting boolits is so stinking easy I don't know why there are so many variables posted.
Turn the pot on, heat the mold and I don't care what make mold it is or the alloy, it will work. It is so far from rocket science it is unreal. Guys cast with junk molds over a fire hundreds of years ago but now you need a computer or you can't make a boolit.
If you let a new caster think while he casts, he will have better luck then forcing all kinds of junk on him.
The very worst thing you can do to a new fella is to talk him into a 6 cavity.
I have hundreds of molds and if every one needs a special technique and a book of records, I will never cast again. [smilie=l:
This mold needs 725.12675* and this one needs 4.7756897 seconds before cutting the sprue----ARE YOU OUT OF YOUR MIND?

[sqlbullet]

I run my pot between 675° and 700°. My cadence has sprue's cooling for about 5-7 seconds, then I cut, drop and fill the mold. If I see heavy frosting I slow it down a little.

I set my pot so the temp creeps up. When it hits 700°, I dump the sprues I have cut back in, stir a little and keep casting. This cycle usually takes about 5 minutes and keeps them temp nicely between my min and max. I have also tried cutting the sprues directly back into the pot, but it doesn't work as well for me.

When I run 6 cavity molds, I usually run two. The sprue gets to cool for however long it takes me to pick up the other mold, cut, dump and fill.

But, I run all my two cavity molds the same regardless of weight or caliber, and all my six cavity molds the same. I agree with 44Man. If each mold has different 'rules' that is too much for me to remember.

There is one thing that is really important in my mind to maintaining consistency: Your bullets need to fall the same every time. Doesn't matter if they just fall free, take a tap, or take three wacks. But, all the cavities need to dump together, and it needs to be consistent. If it varies, or if some cavities stick while others don't, then you are getting inconsistent heat transfer to the mold, and that will cause issues.

To this end, if I have a mold that is inconsistent, it gets polished with a cast bullet chucked up to a drill and coated with toothpaste. This is repeated until I get consistent results. Most of my molds now just drop when I open them, which is really nice. I have one mold that takes a tap, and another that is new and needs polished.

[Bret4207]

happy.
You keep saying EGO, why don't you say EXPERIENCE?


Because that's the way you come across. The ONLY way to do things is YOUR WAY and there's no use in talking about it beyond that.

FWIW, I've had the same basic experience with people telling me something won't work, but it works for me. I don't assume that's because I have any magic skill or experience, but rather that I'm doing something a little different than the other guy that works FOR ME. People, guns, moulds, etc. all differ.

[kelbro]

There are as many different casting techniques as there are casters and alloys and any of them can (and do) produce good, usable boolits.

[Hastings]

by this time you are ready for a break ..set everything up to pre-heat or stay hot.. while you fish out the wire basket from the bottom of a 5 gallon bucket {4 gallons of water}

these wet bullet go to a towel to dry and start seperating by caliber..while awaiting the pot to catch heat wise...

You don't find your pistol caliber boolits get too hard when water quenching, especially the .45s? If WW lead, you're BHN is likely at least 22 rather than the 11 BHN or so that air cooling would give you. I would worry about proper obturation at that hardness for such a low pressure/low velocity cartridge. It might be useful to chrony and test groupings of shots using both water quenched and air cooled boolits if you haven't already done so.

[geargnasher]

Hastings, I didn't read anywhere that he said he was having any problems at all shooting his boolits.

Gear

[Hastings]

Hastings, I didn't read anywhere that he said he was having any problems at all shooting his boolits.

True that. Perhaps the subject of boolit harness and obturation for .45 acp would best be brought up somewhere else anyway. Sorry for hijacking the thread.

On the subject of casting temperature, htower099's idea of using more than one mold is a good one. I started out trying the ol'press-the-mold-on-wet-towel method, but I've found 3 casts each alternating between two molds allows me to maximize my pace. I do agree with some posters here that this is a lot simpler than some folks make it out to be. There's room for a wide margin of error with casting and mold temperature. With a really hot mold, you'll just wait longer for the sprue to set and find yourself with less shiny boolits. Not a big deal. If you're mold is too cold, it's very noticeable since the boolit will be deformed. Just cast again and perhaps the very next one will heat the mold enough for keepers.

I tend to keep the temperature of the lead in the pot on the cool side, because I'm a ladle caster and want to minimize oxidation and the necessity to flux. After awhile, just what the surface does after a few minutes tells you all you need to know without ever having to use a thermometer.

Just my 2 cents (at least on the thread subject this time)

[Bret4207]

True that. Perhaps the subject of boolit harness and obturation for .45 acp would best be brought up somewhere else anyway. Sorry for hijacking the thread.



If the boolit fits to start with, obturation neither desired or beneficial. In fact, I'd aim to avoid it if possible.

Someone noted there are as many different methods and ways to accomplish things as there are casters and loaders. I agree completely, that's why I tend to disagree with people who try and limit people to doing things one way or tend to not keep an open mind about different methods.

[44man]

There are as many different casting techniques as there are casters and alloys and any of them can (and do) produce good, usable boolits.
Now you have the answer. It just does not matter if you get results but to make it complicated beyond reason is not my way. It is just too easy and does not need all the junk science.

[45 2.1]

Now you have the answer. It just does not matter if you get results but to make it complicated beyond reason is not my way. It is just too easy and does not need all the junk science.

Awwwhh.... now we have it. Now we know why you can't get soft boolits to shoot.

[44man]

Awwwhh.... now we have it. Now we know why you can't get soft boolits to shoot.
True but I will never reveal the electronics I cast into my boolits! [smilie=w:

[45 2.1]

True but I will never reveal the electronics I cast into my boolits! [smilie=w:

Yep, that lazer guidance system that looks like a red dot scope guides those lead coated machined electronically enhanced boolits into the groups you show. No human skill needed. Hee hee hee.................

[44man]

Have you seen the bullets that are programed to explode at any distance? Amazing what the military has today. Shoot over a bunker and the bullet explodes to kill anyone behind it.
Then the computer used with a sniper rifle so it only takes the first shot.
Bullets that go through a barrier before exploding.
Here we are in the dark ages with a ladle and a pot of lead! :bigsmyl2:

[45 2.1]

Have you seen the bullets that are programed to explode at any distance? Amazing what the military has today. Shoot over a bunker and the bullet explodes to kill anyone behind it.
Then the computer used with a sniper rifle so it only takes the first shot.
Bullets that go through a barrier before exploding.
Here we are in the dark ages with a ladle and a pot of lead! :bigsmyl2:

I've read about those......... even watched some of the new stuff on dish. But boolits, you really don't know whats possible there.

[Cap'n Morgan]

Casting boolits is so stinking easy I don't know why there are so many variables posted.
Turn the pot on, heat the mold and I don't care what make mold it is or the alloy, it will work. It is so far from rocket science it is unreal. Guys cast with junk molds over a fire hundreds of years ago but now you need a computer or you can't make a boolit.
If you let a new caster think while he casts, he will have better luck then forcing all kinds of junk on him.


Amen, brother!

I always likened casting boolits with baking pancakes: Just make sure the skillet/mold is hot enough, and on you go... The Moment of Zen will come to you along the way.

[454PB]

If the boolit fits to start with, obturation neither desired or beneficial. In fact, I'd aim to avoid it if possible.

Now there's something I've been harping on for many years!

[44man]

Now there's something I've been harping on for many years!
Me too, over and over. Bret is just so correct and even though we don't agree with a few things about casting, he knows what a boolit should be.

[geargnasher]

If the boolit fits to start with, obturation neither desired or beneficial. In fact, I'd aim to avoid it if possible.

Someone noted there are as many different methods and ways to accomplish things as there are casters and loaders. I agree completely, that's why I tend to disagree with people who try and limit people to doing things one way or tend to not keep an open mind about different methods.

Allright, Bret, I like you a lot but you have got to stop misusing the term OBTURATE! I was so confused about it for the first few months after joining this forum I finally looked up the term. Everything you said (well, most anyway) made sense, but it made no sense why you preach the ills of obturation when I find obturation to be one essential thing to achieve for successful cast boolit shooting. After a long time I finally figgered out that what you meant when you referred to obturation was deformation of the boolit, like "bump up", swage, swell upon firing, or just plain start out overized and force downsizing of the boolit in the barrel in an attempt to get a better fit. When I realized you meant that excessive sizing or deformation of out boolits is bad, I totally agree, and also agree that oversized boolits often aren't necessary or even desirable, but going fat is a way to cheat other factors to achieve obturation.

Obturate is a medical and gunnery term that refers to blockage or seal usually in reference to an arterial obstruction or blockage or something like having mud in your muzzle.:p It's derived from the latin obtūrāre, meaning to stopper something up. It is used here, or should be, to mean that you've prepared the boolit, gun, and brass in such a way that the boolit creates an effective blockage in the bore, meaning no gas cutting or the leading resulting from gas cutting. Obturation happens to the bore, not the boolit, when the bore is effectively blocked with a leak-free seal by the boolit on it's trip from chamber to target. Of course it's impossible to achieve 100% obturation, there will always be some leakage, but past a certain point the leakage starts causing noticeable problems, I think we can all agree on that.

There, I feel better now! Maybe I've spared someone else the confusion :bigsmyl2:

Gear

[Hastings]

There, I feel better now! Maybe I've spared someone else the confusion

I'm afraid not. Everything you've said has just obturated my brain. :kidding:

You know you have zero obturation when you fire a gun and it goes bang like it's supposed to, releasing a lot of smoke and fire out the business end. Then when you tip the muzzle towards the ground your boolit falls out. :-P

It might have been posted here 100 times, but here is Glen Fryxell's article titled "Cast Bullet Alloys and Obturation (http://www.lasc.us/FryxellCBAlloyObturation.htm)". One way of using the formula for boolit hardness is: BHN = estimated peek pressure divided by 1,440. I never had real shooting problems with water quenched WW lead for 45 ACP - until I began experimenting. While I wasn't getting leading using my .001" to .002" oversized boolits, they likely weren't engaging that shallow rifling as good as they should. When I tried air cooled boolits, they were a bit faster (not as nearly as big a difference as in the article however - maybe 15 fps) and my groups were considerably tighter at 25 yards. Keep in mind that I'm using a 1911 with rather wife-friendly loads that run under 800 fps.

Obviously the best way to get obturation is with boolits the right size, which means a bit bigger than your barrel. If smaller, it's unlikely deformation due to pressure in a low pressure caliber will happen enough to cause proper obturation no matter how soft the boolit is because of the excessive gas cutting. You can't get deformation without at least some initial obturation, and .001" over size is probably enough IMO. So yes, the most important factor is "right sizing" your boolit for your gun, and the boolit hardness is secondary and dependent on the first factor. Both are important for minimizing gas cutting and engaging the shallow rifling of the 1911 .45 ACP I think. But as there are so many variables involved, I suppose you can't make rules about this stuff. In other words, if it ain't broken, it's not worth trying to fix!

[lwknight]

If the bore is not fully obturated , you will have a leading problem.

[357shooter]

The bore is obturated by the bullet obturating. :kidding::kidding:

[Bret4207]

Yeah, I know obturation is the wrong word. We went through a long thread here a while back and the engineers in the group came up with the right word, which is something similar to "abride" or "abrade" or "ebride" and I agreed to use that word, then promptly forget it!!! CRS strikes again!!!

So, I use "obturate" because 99% of the people here know what I mean at least in the basic sense. when we say "obturate" we mean the riveting or swelling of the boolit from pressure on firing. Many people have this idea that if they punch the base of the boolit hard enough the whole thing will swell up to throat size, fill the bore, force the lube against the barrel walls and they'll instantly have perfect dynamic fit. To me, that's a lot to ask of our boolit and our powder charge, is an event that is really rather difficult to perform to the same level over a long string of shots and a complete insult to all the work we put into finding the right sized mould, casting perfect boolits and putting a lot of TLC into all the rest of it if we're simply going to mash the boolit into putty in the faint hope it'll fit the barrel better! And of course there's the whole "It's got to be HARDCAST" which means you need even MORE pressure to hope to get that swelling effect.

So, after countless hours reading the thoughts of famous, infamous and relatively unknown authors, plus the writings of the brethren here and elsewhere and even more hours in the loading room and in the sand pit, I came to the conclusion that FIT IS KING, that if we start with as close to perfect fit as we can in the first place then the last thing we want to induce is excessive "obturation" and that depending on obturation with harder alloys ( harder than pure lead) and smokeless powder is a fools errand.

I apologize if I confused anyone. I'm just a dumb hick sheep farming, barely made it through high school, everyday schlub whose writing skills sadly lack in producing clear and concise communication of what it is I'm trying to say.

[44man]

Yeah, I know obturation is the wrong word. We went through a long thread here a while back and the engineers in the group came up with the right word, which is something similar to "abride" or "abrade" or "ebride" and I agreed to use that word, then promptly forget it!!! CRS strikes again!!!

So, I use "obturate" because 99% of the people here know what I mean at least in the basic sense. when we say "obturate" we mean the riveting or swelling of the boolit from pressure on firing. Many people have this idea that if they punch the base of the boolit hard enough the whole thing will swell up to throat size, fill the bore, force the lube against the barrel walls and they'll instantly have perfect dynamic fit. To me, that's a lot to ask of our boolit and our powder charge, is an event that is really rather difficult to perform to the same level over a long string of shots and a complete insult to all the work we put into finding the right sized mould, casting perfect boolits and putting a lot of TLC into all the rest of it if we're simply going to mash the boolit into putty in the faint hope it'll fit the barrel better! And of course there's the whole "It's got to be HARDCAST" which means you need even MORE pressure to hope to get that swelling effect.

So, after countless hours reading the thoughts of famous, infamous and relatively unknown authors, plus the writings of the brethren here and elsewhere and even more hours in the loading room and in the sand pit, I came to the conclusion that FIT IS KING, that if we start with as close to perfect fit as we can in the first place then the last thing we want to induce is excessive "obturation" and that depending on obturation with harder alloys ( harder than pure lead) and smokeless powder is a fools errand.

I apologize if I confused anyone. I'm just a dumb hick sheep farming, barely made it through high school, everyday schlub whose writing skills sadly lack in producing clear and concise communication of what it is I'm trying to say.
Do you see how close we think? Expanding a boolit to obturate will always result in poor results.
A boolit that fits will obturate or seal the bore.
However when you say excessive obturation, you should say EXPANSION instead.

[Bret4207]

Nope 44, that term is used for what happens when a boolit hits our game. That would just be more confusing. I forget the correct term. Maybe I'll look it up.

[44man]

Nope 44, that term is used for what happens when a boolit hits our game. That would just be more confusing. I forget the correct term. Maybe I'll look it up.
OK, call it SLUMP, deformation or just destruction. :mrgreen:

[geargnasher]

Dumb sheep farmer my ****. You probably helped solve as many member's problems here as anybody. I just had to give you a blast because I got confused once and actually had to figure out something for myself.:D

I missed that thread, if you get time I'd like to know what the "official" term really is. Then I can start using that instead and really confuse everyone!

Gear

[pearson1662]

Thanks for your "Pocket Guide". I may not be able to live up to the letter but will endeavor to the spirit of the science...or art...

How much are those NOE mould thermometers, just out of curiosity?