Weight differences in same bullet/alloy.

I will try to make this as simple of a question as possible. I bought 5 lbs of raw un-alloyed lead. I put this in my Lee pot that was cleaned before using this lead. I used only this lead. I cast 405 gr. 45/70 bullets. Air cooled. When I was done with the 5 lbs, I was done. I then started sizing/lubing them in my Lyman 450. After I had sized for a while, I decided to start and weigh and sort them and put them in containers because I have limited space on my bench. Here's where it gets strange and my question. I weighed and sorted about 2 dozen bullets after being sized and lubed and came up with a variance of 8 full grains of difference. I have never cast with raw lead and have mostly used ww. My variance with it has been 4 full grains over a run of a 100 bullets. So is this acceptable for raw lead and a norm or is there something wrong going on here with either me or the lead. Please comment.

if the fill out was good the variance was from air bubbles in the alloy.
if the fill out was poor that would be where your variance come from.

I try to pressure cast when I can with the close to pure alloys, get the mold hotter, keep the lead at a higher temp, and keep the pace up.

If you were casting with the Lee 405 HB, be aware that the bullets sometimes can come out with a "skirt" around the hollow base. It's easy to get a small weight difference when the base is not 100% uniform. I've had this happen many times and at the moderate speeds I shoot my 45-70 stuff it's still my most accurate bullet.

I have cast some minne for my 58 cal and they are hollow base that found out that you need to check the inside of the hollow base that some time there is a air parket in them and you will not have it shoot the same as the others.I was usen pure lead for it.

I thought most people weight sorted prior to lubing.

This Lee mold is not the hollow base model. Its the plain base model. And most of the time I do sort my bullets before size/lube but it just didn't work out that way yesterday.

This is exactly what I was gonna say!

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Originally Posted by runfiverun

If the fill out was good the variance was from air bubbles in the alloy.
If the fill out was poor that would be where your variance come from.

I try to pressure cast when I can with the close to pure alloys, get the mold hotter, keep the lead at a higher temp, and keep the pace up.

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Larger bullets are more likely to get air pockets. Especially if you swirl in the lead, something that may be happening without you even knowing it. PRESSURE CAST at Higher temp! Try an Alloy with some Tin!

What is "pressure casting"?

I'm getting ready to start casting either 0.600 or 0.610 round balls for a flintlock (still have some experimenting to do with bought round balls till I know what the rifle prefers), and I've read on ML-oriented sites that casters of round balls prefer to ladle larger diameter balls for this very reason....this variance in projectile weight. I'm not sure I understand the why's of it, but the theory is that ladling avoids the air pockets/voids internally.

The pot a friend gave me is an old Saeco bottom pour. Ways to prevent voids are of high interest to me. Thanks! :)

I'm new at casting. Tell me what is acceptable weight diff. in a boolit. Lets use a .309 170gr flat point. I'm using WW and my cast are running from 172-176 gr. with gas check.

Tenbender, Closer weights would be better but, hey pretty good for a new guy! What you've made are great for casual shooting or plinking, just not quite ready for national competition yet. Check the cavities to make sure they both drop the same weight and if they do, work on your consistency and cadence. Don't get discouraged, it takes time to learn and they all shoot. Trigger time's fun and important, too! Just so you know, I haven't mastered that mold yet either. Mine's a little sticky, throwing off my cadence.

This thread might give you some ideas on absolute boolit consistency...
http://castboolits.gunloads.com/show...stency-applied

You said you used five pounds of lead in a clean LEE pot and ran until done correct? When I run the LEE I tend to only run to about half way down the pot. My reasoning is that the pressure of the pour is changing as the pot drains with each pour. I want an even flow rate at a set temp so I run a PID as well. My weight variance seems a lot better nowadays.

Try this thread too. http://castboolits.gunloads.com/show...end-about-temp

I thank all of y'all for your input. On the next go around I will try some of your suggestions. As for the moment, I kept the greater bulk groups, ie. 425 grs. 426 grs and 427grs. I recycled the 421-424's and 428's. I did have a chance to get them out on the range today. I also tried a powder that was not listed in my manual but a similar burn rate, Varget, was close to the IMR 4064 I used. I started at 32.5 grains and worked up in 1 grain increments to 35.5 grains. I did use poly fill in the case and a crimp that measured .002 smaller than a sized case. The first 4 round group was the best of the bunch at 50 yards. I thank everyone on this group for helping with all the information you put out. Attachment 132771