Hello everyone,

I have been experimenting with casting temperatures with my iron Accurate Molds. So far, I think a temp of about 725 is best. Tuesday, I thought I had one of my best casting sessions ever, until I had a chance (last night) to inspect the bullets. There was a problem with the bullets not wanting to drop, and upon inspection, a large percentage had damage from the attempts to dislodge a stubborn bullet from the mold. PHotos attached. I think there is a burr on the mold that is causing the problem. 
What is the best way to diagnose the problem?
If there is a burr, what is the best way to remove it?
Any suggestions would be appreciated!
Thanks!
Joe S

another shot

I'm curious, too.  Have this issue from time to time. Doesn't seem consistent.

Joe; what is your lead alloy?  I use 20:1 and cast at 800F.  I use aluminum Accurate Molds and if I heat them really good on a hot plate, they start producing very good castings quickly. Usually, a moderate whack with a wood stick drops the slug. (sometimes, two whacks  )

Someone once advised me to check the edges of the mold cavity halves for burs or "lips" at the edges and carefully remove them.  That did help with an iron mold I was having "dropping" issues with.

Mike.

I have found that for alum molds, I need a temp of about 850Deg, but for an iron mold, if the temp is over 750 I start to get lead seepage into the vent lines and fins,  which are  hard to remove in the grease grooves, so I am trying to keep below 750 for that reason. I found what appears to be the culprit, or at least one of them, this morning with my Optivisor. A burr at the base of the bullet cavity that extended into the cavity. No idea how that happened, I am very careful with my molds, but it was there plain as day. I removed it with a fine semi-circular honing stone, tried to be as conservative as possible in removing metal. Hope to try it this afternoon, will give a report and post photos of the mold if the problem is not fixed. 
I ran some of the scratched bullets through the lubrisizer, in most cases, the scratches get ironed out, will lube up a sample to test how they shoot and post the results. 
The bullets that dropped without problems were very good, (double cavity mold) so I hope I can get a good batch today or tomorrow.
I am using 30/1 rotometals alloy. I accidentally posted the same photo twice, was having a difficult time getting a photo that clearly showed the damage without getting washed out by the light. 
Thanks!
Joe 

The burrs are not, usually caused by miss handling by the user but, much more likely, caused by a dull cutter when machining the mold.

Have you tried smoking the mould???

I don't cool my molds as once I get a rhythm that works I just keep casting at the same pace. If I have to stop for any reason I leave the last bullet in the mold to retain the heat and then dump it when I restart my casting.

Hello everyone, Thanks for your replies! I was able to cast today and took your advice and brought the  lead temp up to just under 800 deg, mold temp got up to  a little over 300 by the time I quit.
Total cast= 116, Total keepers=92, rejects remelted=7, sighters and practice bullets = 17.
Match grade= Perfect bases, (photo to follow), bands completely and evenly filled out, no flaws except very minor surface imperfections which will be erased when sized. 
Practice and sighters= very minor defects such as tiny dimples or very small areas of imperfect band fill out. 
Issue: toward the end of the session, I started getting some flashing at the mold lines. I am using locking handles to consistent pressure is not the issue. I kept the ones that I could scrape the flash off with my fingernail, now sure how they will shoot, will test ten against some that done have the flashing. 
Weight:  a few were under 320.6 and they went to the sighters, which otherwise we not weighed.
I sorted per .1 grain. Twenty two were between 320.6 and 320.9
Thirty seven were between 321.0 and 321.4
Twenty three were between 321.6 and 321.9
Nine were between 322.0 and 322.3
I had one at 320.3 which went with the sighters because it was quite a bit lighter than the others. 
Conclusions:
1) As the temp of the mold got higher toward the end, and that is when I started getting the flashing. I dont like it because I dont know the extent to which it will  affect the group, will try to do some testing vs Match grade so see if I can notice a difference.
2). Lead temp at or just under 800 deg produced great bullets. My gas valve is quite coarse, have to keep fiddling with it to keep as close to the target temp as possible
3)  I will try to get the mold hotter to start with, but find the sweet spot that produces good bullets without flashing. Something around 300-310 might work
4) Not sure how I should sort them for shooting. Started out years ago sorting to one grain, which might be the most practical. Then I sorted to half grain, and last year .1 gr,. My bench skills are not good enough to be able to detect a difference so far. Obviously, the heaviest bullets   are most likely to have no voids. the question is where to draw the line. Considering that the scale has an accuracy  range of .1 grain, there could be a spread of up to .3 grain, so I am thinking that sorting to less than a half grain is probably not worth the trouble. Would like to hear your views on that one. 
to be continued!
Joe S

Here are some photos of the casting session: I know you have seen bullet bases before, but just want to show what I consider to be good bases, the  sprue marks are visible but perfectly smooth
Bases:

a bullet with flashing

The honing stone used to take out the burr. I was reluctant to try it but when you are at the bottom of the well looking up, what difference does it make? I wasnt getting good bullets so I figured I had nothing to loose. Seems to have worked out all right.

Much better but a gas flame should maintain an accurate temp. Do you let it stabilize after the lead has melted? 775 should be a good temp. I preheat my moulds on a cheap (like $13) Walmart hotplate set to medium. I start them before I melt the lead being careful to have the mould basess fully in contact with the plate. Have you tried using 2 moulds in succession (fill 1, set aside, drop 2, refill 2, drop 1, refill 1 and so on)? This helps to maintain an even temp on the moulds and guarantees the sprue is set evenly hard. Once you have the rhythm it goes quickly since there is no time wasted waiting for the sprue to set. I would be suspicious of that lead showing in the far end of the mould joint line. That area should be just as tight as the joint near the mould hinge.

Joe,
Half a grain would be a good place to start when sorting bullets.  Two things that I have learned about getting weights consistent is to use a small fan to cool the mould and the second is invest in a pair of the locking handles that BACO sells.  The last batch of bullets I cast were 2-2-96 alloy at 740 degrees and out of 37 I had cast 32 were +/- .15 of a grain, my best yet.  The other 5 were 3 tenths more because I let the mould get hotter.

Cheers,
Steve

I have found, and this just me, that the final weight of the bullets depends on the amount of lead in the dipper. If I am consistently getting exactly the same amount of lead in the dipper then the bullets tend to be very closely matched in weight. I'm not that good at estimating the volume of lead in the dipper or ladle so I picked up a used RCBS older model promelt melting pot. I have one I use for pistol bullets but thought maybe I could get closer to matching weights if I could control the volume/weight of the lead going into the mold. It seems to work for me but took some careful messing with the flow rates to get consistent results. I have cast bullets for more than 50 years with ladles/dippers and this is now the best matches I have achieved for large caliber bullets cast using pure lead and pure tin.

Todays update:
I casted (any English majors out there, not sure if that is the correct word or is it "cast"?) some bullets today, alternated between a 250 gr mold and the 315 mold, both from Accurate Molds.
Lead Temp= 780-800
Mold temp=  300
Hot plate set at Medium
Help the ladle to the mold for a count of 5 ( which is less that what I was doing before)
Overall, quality was very good. Only had to remelt 4 bullets. Total cast was 95, less 4 rejects, 19 for practice and 72 match keepers. 
I got some flashing when the mold got up to 325 deg, had to lower the temp on the hot plate. 
I did not get as many bullets this trip because I took a lot of time to inspect periodically, so I could adjust mold or lead temp as needed. Bullets from each mold were all within one grain weight ( with two exceptions), which is about as good as I am going to get. 
Based on these results, I think this technique is meeting my requirements. The proof is on the paper, of course, and that depends on the nut behind the stock, the wind and to some extend the orientation of the moon and planets. 
Using two molds has been my habit for many years, not sure how much of a difference it made but it did not hurt, and may have helped keep the mold temp steady. 
Adjusting the temp. of the lead and  mold and reducing the time of contact with the mold and ladle were key improvements which were suggested in your replies, THANK YOU VERY MUCH!
If I make any more "discoveries" I will post them. 

Thanks!
Joe S

Thanks oneatime!

I do not intend to check the mold temp on a regular basis or to inspect the bullets while casting, except to take a quick look at the bases after the sprue is cut. However, I do like the idea of using the hotplate to keep the molds warm when I am fluxing or for some good reason have to interrupt the casting. 
I have tried lots of methods and for me and the molds I am using, holding the ladle to the mold for a little longer, such as a count of five, seems to get better results. When I am casting my 315 gr bullets they are for benchrest only and I want the best possible bullets, even if it takes a little longer. For 45-70 or 8mm Mauser or .30 cal, I might pick up the pace a little, the requirements are not nearly so demanding for those rifles (three position High Power at 100 yds.)
No doubt there is room for improvement and I am always willing to try recommendations, and the help that I got in this thread has paid off!
Thanks everyone!
Joe S