BPCR shooters Your advice needed

[wyoduster]

Using a PID w/RCBS promelt... bottom pouring 40 cal 400 gr. bullets using 20:1 lead
What have you 'all found to be the optimal temp. to pour??
I know I've been told you can't bottom pour these molds accurately but I must try..
Asking for advice.. and opinions. :coffeecom

[kokomokid]

I ladel pour, but light moulds like lyman snover I cast at 750*-760* and heavy thick moulds I go to 800* my therm. Each mould has its own likes and mould temp is as important as alloy.

[country gent]

I also ladle cast these heavy bullets but if your bottom pour pot can be adjusted up for aenough flow on the steam it should worlk okay. I run 700* - 750* with 20-1 or 30-1. A few tricks to remeber are a solid fast fill to get mould filled while lead is molten from tip to base. Pour a large sprue as big as you can even if a little runs off. This is harder to do with the bottom pour pots. Ladle casting I dont pour a sprue but fill the cavity and then let the ladle empty into the sprue running off the side back into the pot, this keeps the base hot and molten longer helping fill out and allows time for air gasses to get out. Alot more is going to be determined by what the mould blocks want also. Some block sets like pressure pours where the blocks are in contact with the spout sealed and held for a few seconds after full. some like a swirlled stream into them. some do fine with a straight quick pour from a little ways away.I cast with 3 diffrent 40 cal moulds a Lyman 400 grn snoover, steel/cast iron blocks. AN old west 400 grn nasa bullet 2 cavity brass/ bronze mould and a old west 400 grn nasa single cavity brass / bronze mould. I have vented the sprue plates on these moulds to allow control the run off. A 4 hour session with my pot will yeild around 500 bullets in the towels. I pre heat the moulds on a rack on the side of my pot. the first 8-10 pours go back into the scrap automatically. I then start casting serious and maintain a fairly quick pace. ( my pot holds 140 lbs or so of alloy and is gas fired) I run at 700-750 degrees and flux about every 200 bullets. WHile fluxing the moulds sit on the heating rack. At the end of the session ( 4-5 hours is about my limit with these heavy brass moulds) I have close to 500 bullets that are almost all with in 1 grain of each other in wieght.

[cajun shooter]

To say one temp setting is a standard to go by is asking too much. All pots differ in what the dial states and the actual temp being delivered. Only those temps checked by test equipment are actual. Bullet design also plays a large part in how each mold reacts to those temps and then we have mold material. This all adds up for a lot of variables.
The only way to find the actual numbers for you are obtained by the old trial and error testing.
I find that the ladle pour method at my setting of 7 1/2 on my pot works when I'm pouring the 45-70 bullets that weigh 400 and above grains. My largest bullet that I pour is a 535 grain from the Saeco 735 mould. I use a mixed 20-1 alloy. Take care David

[powderburnerr]

I cast at 745 for the soft alloys and for the 40s use a faster cadence than with the bigger 44s and 45s

[Dragonheart]

I honestly have never cast that large of a bullet, but my Pro Melt reads pretty close when I have checked it with a digital probe thermometer. I would clean the pour spout to make sure I had full flow. A welder's tip cleaner works well for this. I do run 4 cavity brass molds, which like it hot, so I would suggest setting the Pro Melt temp at 800, giving it enough time to reach full temp. Use a hot plate to heat the mold to approximately to 350 degrees and starting from there. I would increase the mold temp if that doesn't get you started. If the first bullets frost you know you are getting close to running keepers as the mold cools down.

[GabbyM]

OK
Set up a small cooling fan. Ten dollar plastic thing generally purchased by menopausal women for there desktops.
Run the lead very hot as you would run pure lead.
when or if you start to get pitted crystal surface and or shrinkage, usually in the bands , then let the mold cool under the fan longer. Once you get started into the void of casting fever. You make adjustments to the melt temp, mold cooling time and time between pours. A sweep second hand clock on the wall helps. Once you get things all figured out. Maybe fifteen minutes or perhaps an hour. Dump all your bullet pile back into the pot then start casting with your qualified setup. Since big bullets like you are working with will have huge deviation in weight and diameter after making any changes. Maintaining consistency in your metal temp and timing routine will yield near perfect boolits.

I've cast many thousands of Magma 405 grain 45-70 bullets that have multiple lube groves. Using a Magma master caster machine.

IMHO it's more reliable to maintain your cadence with a machine or bottom poor pot than it is with hand cast ladles. I use the clock on my wall but for the big bullets for competition I can understand why some casters use the temperature probes in there molds. I've never felt the need for that control actor. Suppose what I do is a controlled steady environment. With your 1:20 alloy I'd start with a thermometer temp in the pot of 750 degrees. When the mold gets to hot and your bullets start shrinking let the mold cool longer rather than turn down the lead temp. By shrinking I mean when the bands loose there sharp edges and the middle of the bullet is smaller diameter than the base and front band. Crystal surface will appear in antimony alloys but not so much in pure lead or tin and lead alloys.

Only bullets I've been forced to pressure poor with a spigot ladle are long skinny rifle bullets and my 22 caliber Lyman 225646.
IMHO any bullet that can be filled with a ladle not being used to pressure the mold by contact with the spigot can be filled with a bottom poor pot. Then with a Lee pot and some others they have a spigot where you can push the mold up on to pressure the mold cavity. Performing the same function as a pressure poor ladle. Old adage is there is more than one way to skin a cat. Will also add that IMHO a higher percentage of casters could find success in the form of small weight deviation with a ladle pressure poor technique on large bullets than any other. Since the pressure in the mold will cancel out other variations. But it's a lot of work. Easy way is to pay attention to what you are doing then get it right and keep it right. Sort of brawn vs brain. I pressure ladle poor my Lyman 225646 because that's how I can get those little nose groves filled out on every single bullet I cast. Bullets shoot great in my 222 rem so I endure the process of using a ladle to apply pressure to overcome a hard to fill out mold. Other 22 molds will free poor any which way I like. I've never seen anything special about big 45 caliber molds other than the naked eye can see the imperfections better. Then percent weight deviation has a larger grain number on the scale. Have also never understood why some casters think casting 22's is hard in any way. You simply adjust things until it works. Don't think in terms of how many bullets you'll cast per hour but rather how to get perfect bullets. Production will be what it is at our desired quality . With 22's for instance one must cast fast to keep the mold hot enough. Which I nice since we can run through 222 ammo like I used to run through 22 rim-fire as a kid.

[wyoduster]

Thanks guys.. I am having a little shrinkage around the bands or maybe should say they aren't filling out like they should. Is that due to lead not being hot enough???

[Spruce]

Hello Duster,
Which PID did you go with? I ordered one , but have not heard back from the guy yet.
I hoped some one would do a large group buy of parts for PIDs.
Spruce.

[Dragonheart]

Yes, I don't think you have your lead/mold hot enough. When I commented before I am using 4 cavity 230 gr. brass molds, which tend to hold the heat better than aluminum. When I am running two molds I set my Pro Melt at 825 and bring my molds up to 400-450 degrees on an induction hot plate before starting. I check my mold temp with an inexpensive, but accurate infrared thermometer. By the second or third pour I will be getting keepers from there on.