Casting the Perfect? Bullet

Omaha Poke · Post by **Omaha Poke** » Sun Mar 14, 2004 5:35 pm

On nearly everyone of the internet board sites lately, I have seen shooter/casters asking "how do you cast and achieve tolerances of +/- less than .5 grs?" To be honest with you, I didn't exactly know how I was able to do this, it just seemed to happen when I cast.

Yesterday, I was going to cast, and decided to see if I could figure out why I got consistant results of +/- .3 grs or less in a run of 100 bullets. I was going to use my Paul Jones AA Smerker mould designed to drop a 570 gr bullet when using 30-1 alloy. I use a propane powered pot and a Rowell bottom pour ladle. I leave the pot full of alloy when I shut if off each time, and so I just put the mould on top of the alloy to heat up as the alloy heats. By the time the alloy begins to melt on top, the mould is hot and the molten alloy does not stick to the outside of the mould. I then rest the mould on an asbestos welders glove while I give a quick flux, and then start casting.

Usually the first five or six bullets just bring the mould up to optimum casting temp and are dumped into the sprue box for later re-melting. After about 5 or 6, I then start looking closely at the base of the bullet while it is still in the mould. If there is the slightest sign of round edges on the base of the bullet, it too gets dumped. I only keep bullets where the base is flat, no sign of draw down of the alloy, and where all edges are sharp and perfectly filled.

Every once in a while, either due to a change in temp of the alloy due to adding the sprues, or just sloppy pouring on my part, I will notice a slight rounding of the base of a bullet. I examine all the bases while still in the mould. It is easier to spot a base which does not look perfect while still in the mould and then it can just be dumped into the sprue box. Here is where I believe my particular success at casting very uniform weight bullets lies. EXAMINE THE BASE OF THE BULLET IN THE MOULD, REJECT THOSE THAT ARE NOT PERFECT LOOKING.

If you accept those bullets without perfect looking bases and mix them with others that may be nearly perfect, you will undoubtedly end up with unacceptable spreads in the weight of your bullets.

Yesterday just to check and see if this theory had merit, instead of dumping those bullets without perfect square and sharp edged bases into the sprue box, I kept them separated from the good bullets and when done casting, I weighed them in there separate batches.

I had cast 156 bullets in about 2 hours and 36 of these were in the sub-standard category that would normally have been rejected directly from the mould. The other 120 were what I would normally have accepted.

On weighing, I only had two bullets out the the 120 that did not fall withing 571.2 grs to 571.8 grs. (+/- .3 grs) Out of the 36 that I normally would have rejected the variation was from 568.4 to 570.8 grs. Well out of the normal acceptance range I have for my casting. I didn't include any bullets that showed a sign of draw down of alloy in these, just imperfect edges.

I also examined the rest of the bullets including the driving bands and grease grooves and found not voids on any of them, no voids of inclusions on the bullets in general. Everything was equal except the edges of the base.

I guess I should have prefaced this diatribe with the fact that the bullet you cast will only be as perfect as the mould you use, your technique, your ability to detect an imperfection in the cast bullet itself and willingness to settle for only the best you can produce with what you have.

I know there are other reasons for weight variation, but I think this is about one of the best starting places for someone to begin sorting out why he/she may be having trouble.

Hope this helps someone, Randy

Clarence · Post by **Clarence** » Mon Mar 15, 2004 9:30 pm

Omaha Poke,

Good post. You are obviously doing a lot of things right to get that tight a variance.

I agree with your practice of immediately remelting any bullet whose base does not look perfect. No sense keeping them-they get harder to throw back in the pot, and you start to rationalize that they might not be that bad... First thing you know, you're shooting garbage, don't have confidence in your bullets, and wondering why you can't hit turkeys and rams consistently.

In addition to what you said, I cast with a clock with a second hand. For temperatures less than 60 degrees, I can cast one bullet every 40 seconds (your monsters may need to be cast a little slower), so I cut the sprue 30 seconds after I first fill the bullet, and then give myself 10 seconds, to drop the bullet, close the mould, and get ready to refill. I find that is a lot more accurate than trying to count seconds after the sprue hardens.

I cast 250 bullets with perfect bases. Saturday from a Fred Leeth Creedmore mould. 224 of them were in a range of 545.3-555.0 grains. Most of the others came from the initial cold mould, when I didn't cast quite enough before beginning to save bullets, and times when I added a pound of lead to my Waage pot (If I preheat three ingots on the top of the pot, I get a consistent 0.3 grain drop when I add lead to the pot.) It would be easy to discard 3 bullets each time I add lead, but I believe these bullets are good, just lighter because the temperature of the melt falls off for a couple of minutes.

Consistency is the watchword:

Rule 1--Do everything the same, every time.
Rule 2--When in doubt, see Rule 1.

Omaha Poke · Post by **Omaha Poke** » Mon Mar 15, 2004 10:49 pm

Clarence, did you make a mistake in saying that your bullets weighed between 545.3 and 555.0 grs.? That is a spread of nearly 10 GRAINS!!

A little later in your post you are talking about.3 grs drop.

I am not sure that we are talking about the same thing, or we (I) am not understanding what the other is saying. When I say that I have a .3 +or- variation from one bullet to the next, I mean that every bullet I keep from the casting session falls within that specified norm.

I have never timed my casting, either by seconds, or minutes, I just cast however many I might need at the time, and then a few extra to allow for imperfections.

The lighter bullets, whether due to a decrease in the temp, or whatever reason, should also be discarded or used just for something like offhand practice. I wouldn't think of using them in a match, or while trying to work up an accurate load. It isn't worth the trouble.

As you say, consistency is the watchword.

Rrandy

Bumper · Post by **Bumper** » Tue Mar 16, 2004 1:32 am

Paul Matthews had a book published in 2001 with the title, "Casting Premium Bullets for the Black Powder Cartridge Rifle". The book is a good read even for experienced casters, containing information and tips designed to put the reader on the road to casting premium/match quality bullets. Rbump

mrrangerman · Post by **mrrangerman** » Tue Mar 16, 2004 7:50 am

Omaha

Hi I'm fairly new to casting, and I have some questions for you or anyone that can help. How often do you FLUX?? and how much flux do you use?
I cast for my 43 span. last night, I got very good bullets 385.5+ 384.5- most, 95% being at 385.0 but I was getting a buildup on the top of the pot. It's not dross, it almost looks like the metal maybe coming apart, But then I was reading someplace its very hard to get the metals to seperate. I'm casting a 25-1 mix from a waage 4757 pot I don't have a therm yet so I'm not sure of my temp, my guess is about 800 - 850 but I could be way off. Any ideas on what is going on?
Thank you very much. Dan

pcc9433 · Post by **pcc9433** » Tue Mar 16, 2004 9:10 am

Am using 40 cal Steve Brooks 420 grain mould, Waage Pot, 750 degrees. Couple of things I have learned that might help another caster....
If you notice small inclusions in and around the nose of your new bullet that look like trash in the lead....in my case they were from pouring the lead into the mould with too much height on the ladle. If the lead splashes into the mould it throws little bits up onto the sides of the nose which immediately start to cool and solidify. Meanwhile the nose and remainder of the mould fill up; the little bits of lead that splashed up and are already cool stand out as trash or rough spots in an otherwise good bullet.

On the other hand; I have to finish each pour with some height on the ladle to get the base to completely fill in. Each time I keep the ladle close to the mould for the entire pour; the base is rounded to some degree resulting in a rejected bullet.

Thus I start each pour close to the mould to prevent splashing and end up 2 inches + away from the mould to finish out the bullet base.

I am not an experienced large bullet caster....comments and / or suggestions appreciated.

Ray Newman · Post by **Ray Newman** » Tue Mar 16, 2004 11:51 am

When casting a larger bullet (530 plus grains) , I’ve found that a much higher melt temperature--approx 850 degrees--is needed. @ this temp, the melt flows like water. @ a lower temp, the melt will cool too quickly & will not properly fill out a larger mould cavity….

If you use a ladle, I would also suggest that you drill out the ladle spout several drill sizes larger to aid the flow of the melt into the mould. The melt flows faster & the force of the melt fills out the mould & expel the air. It is also wise to pour a generous sprue as the cooling melt will suck down the melt from the sprue plate.

Flux, I now utilize bullet lube. Prior to this, I used Maganflux, but it rusted the pot, laddle, & is (was) a mess as it seems to attract moisture. I flux about every 30-35 bullets.

A useful item is an old tablespoon securely fixed to a wooden handle. It is ideal for stirring the melt & skimming off the dross. Several holes in the spoon make the stirring of the melt much easier.

To keep a track of the melt temp, I have a hand-held infra-red thermometer. Works well. For info on this useful little item, see the below thread found in the “Shooter to Shooter“ forum:

More Casting Experiences

The March & April 2002 issues of the “Single Shot Exchange” published a very good article on casting-- “The 8-Phase casting Cycle” by Darryl Hedges. I don’t know if it is available on-line. But call to the “Exchange” might get you the back copies or -reprints of the article. Worthwhile article & of course, the “Exchange” is an informative monthly periodical.

http://www.singleshotexchange.com/

McLintock · Post by **McLintock** » Thu Mar 18, 2004 11:33 am

I definitely think that mold quality has everything to do with it. I was using a Lyman 535 Postell and was doing good to keep bullets within a 5 gr margin. I bought a Steve Brooks 540 Creedmore almost 2 years ago, and using exactly the same casting parameters, I can cast 300 and a full half will be from 538.0 to 538.4. The other half will fall within one half gr on either side of this. I weigh each one and put them into 3 weight limits for use. Anything outside this goes back into the pot or is used for practice or foulers. I also got a Butch Ulster sprue plate put on the mold when I ordered it. I think that this helps a lot also, as it helps to give the same sprue amount and pressure on the load for each casting. I'm casting 20-1 at 800-825 degrees, with a Lyman pot and ladle (just got a RCBS ladle), nothing special outside the mold and sprue plate, and drop the bullet soon as the sprue solidifies.