How to avoid "smearing" the bottom of the bullet?

[fjpereny]

I am using a Lee 9mm 124grain mold. I have been having great success with the bullet body, very nice crisp edges and no wrinkles. The main problem that I am having is a tiny bit of smearing when I pull off the sprue. It leaves the bottom of the bullets with a very thin lip hanging over the edge, almost like a bur that needs to be removed.

I tried wiping down the sprue and top of the mold with a very light coating of oil with mild success. I have also tried tightening down the bolts to make the sprue/mold interface tighter.

I would appreciate any tips you have on reducing this problem.

[JSnover]

Wait a little bit longer before you swing the plate. Gives the center more time to harden.

[trapper9260]

Wait a little bit longer before you swing the plate. Gives the center more time to harden.

I was thinking the same also.Need to let it cool alittle longer before you swing the plate.

[Wally]

I press the opened sprue plate on a damp sponge, when the smear starts or you fan wipe off the smear with an oily rag..this will allow you to cast a 4 ~ 5 more casts before you have to repeat

[25ring]

After the sprue solidifies flip the mold over on a damp sponge for a second or two.No more smeared lead.--Mike.

[Yodogsandman]

Learn to count down when to open the sprue plate. Too soon results in smears. Too long results in a raised spot.

[retread]

^^^^
Here's your answer.

[fecmech]

I use something similar to the damp sponge. As soon as spru "flashes" I turn the mold over on a wet rag for about 1 second and then cut the spru. If the mold gets a bit overheated (longer times till spru flashes) I set the base of the mold on the rag for a few seconds to suck the heat out of the mold. I get very uniform cast bullet weights that way with fairly high production rates.

[Soundguy]

Agree with the others, you are trying to cut it before it has cooled enough.

[Grmps]

Don't tighten the sprue down to tight, [THIS WILL DAMAGE YOUR MOLD by wearing out the mold top where the sprue plate is attached causing the sprue plate to be cooked with the top of the mold. this can be repaired by machining the top of the mold flat again] a loose sprue will not smear IF it is flat and you can't see any light between the sprue plate and the mold block.
You could have a slightly warped sprue plate, how a straight edge to the bottom of it and see if you can see any light between them

what alloy are you using?
how hot are you casting? I've found I can get good results between 690°-720°
Are you using a casting thermometer or a PID?

Pictures are always helpful and appreciated in troubleshooting a problem

fjpereny - welcome to CB. If you decided to start casting to save money, forget it. You won't, you'll just shoot more.
Casting boolits (lead bullets) properly is a science, once you know the basics, not a hard science.
There is a lot of good information on CB. The Google search (top right of every forum page) is a gateway to all the knowledge on this forum. IF you can’t find your answer there ask the question (Please be as detailed as possible, pictures help http://castboolits.gunloads.com/showthread.php?344661-Capturing-amp-Posting-screen-shots I would be very surprised if there wasn’t someone on this forum that could answer ANY question you might have)
http://www.lasc.us/Fryxell_Book_Contents.htm
1. Boolits need to be cast .0005 to .003 over the slugged diameter of your barrel for accuracy and to avoid leading. If the fit is wrong nothing else will work right.
a. slugging a barrel (it is safer to use a brass rod or a steel rod with a couple of coats of tape to avoid damaging your barrel http://7.62x54r.net/MosinID/MosinSlug.htm
b. chamber casting https://www.brownells.com/guntech/cerrosafe/detail.htm?lid=10614
or pound casting http://castboolits.gunloads.com/showthread.php?356251-Pound-Cast-instructions-(for-rifle-chamber)
2. the right alloy needs to be used for the velocity and purpose of the boolit (don’t fall into the trap of going with to hard an alloy
Economical way to easily test lead hardness
http://castboolits.gunloads.com/showthread.php?355056-Easier-pencil-lead-hardness-testing
https://i.imgur.com/TGUQsIe.jpg
Some alloys harden over time
http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.ht m
different alloy’s different end sizes
https://i.imgur.com/emuBC2T.png?1
Lead alloy calculator
http://castboolits.gunloads.com/attachment.php?attachmentid=45784&d=1341560870
3. velocity the bullet needs to be pushed hard/fast enough to get the proper spin, have the proper velocity to accurately reach the target but not so hard as to be dangerous or strip the lead off in the grooves instead of spinning the boolit..
Powders range from fast to slow, you need to choose the right powder for your application.
Loading manuals list the best powders for certain calibers and boolit weights.
NEVER use any posted noncommercial load data without first checking to see if falls in the safe parameter for your firearm!! There are several firearms out there that can handle much higher pressures than others!!
Link to free online load data
http://castboolits.gunloads.com/showthread.php?337910-CB-load-data-online-sources

[mdi]

Learn to count down when to open the sprue plate. Too soon results in smears. Too long results in a raised spot.

Yep. My experience too. I haven't cooled just the sprue plate, just waited a bit longer (if I was in a hurry and couldn't wait, I'd get out another mold and alternate)...

FWIW for the OP; quite often a new reloader/caster will post a simple, basic question on a forum and the replies will morph into advanced techniques and theory, often confusing the new guy. Not all bad, as all information is good, just some are overly complicated/complex for a new user's answer. K.I.S.S....

[fjpereny]

I was traveling so I had not gotten a chance to reply yet. I wanted to thank everyone for your advice. I did notice a small hole in the bottom of the bullet, it must still be liquid at the core and it is being pulled out. I will try to slow down a bit and use the sponge technique. I have about 1500 bullets cast already so I am not sure when my next casting session will be, but I will let everyone know.

Regarding the bullets with the slight "burred" edge, are they ok to use as is, perhaps a quick debur on the lip?

[JonB_in_Glencoe]

as others stated, probably opening mold too soon.
But if you still have issues with the smear/burr, if could be a warped sprue plate. You didn't mention if it was a Lee 6 cavity, but since you mention having 1500 boolits cast, I will assume it is. The 6 cav sprue plate is aluminum, and is prone to getting warped when over heated. I have warped a couple of those, and I found it nearly impossible to correct that problem without replacing the sprue plate with a new one. If you are real patient and quite handy... some fine grit sandpaper, a flat surface, and some time, you may be able to correct that problem without getting a new plate.
good Luck

[fjpereny]

as others stated, probably opening mold too soon.
But if you still have issues with the smear/burr, if could be a warped sprue plate. You didn't mention if it was a Lee 6 cavity, but since you mention having 1500 boolits cast, I will assume it is. The 6 cav sprue plate is aluminum, and is prone to getting warped when over heated. I have warped a couple of those, and I found it nearly impossible to correct that problem without replacing the sprue plate with a new one. If you are real patient and quite handy... some fine grit sandpaper, a flat surface, and some time, you may be able to correct that problem without getting a new plate.
good Luck

Yes, it is the 6 mold.

Thanks, I hope I haven't overheated it. I did wait longer (around 6 seconds after the sprue freezes) and I was getting much better results. My first 10 to 20 batches no problems, then the problems started creeping in, maybe the mold was getting too hot?

Anyways, I am getting pretty decent results and I have a ton of bullets now.

I have never even reloaded before and here I am sitting on a mountain of lead lol!

[toallmy]

Test your new loaded ammo in small batches to work out your load , no one enjoys disassembling loaded ammunition . Be safe and have fun welcome to Cast Boollits .

[JonB_in_Glencoe]

Test your new loaded ammo in small batches to work out your load , no one enjoys disassembling loaded ammunition . Be safe and have fun welcome to Cast Boollits .
That's great advice for a newbie.
back in the day, I would always want to load a large batch when loading pistol ammo (actually I still do), but now whenever I use a new powder or even just a new load of the same powder, I always load up about 50, then head to the range and test fire them.

[samari46]

I had a Lyman mold that the spru hole was not tapered all the way through. It ended up short by about 5/32nds from the bottom of the hole. Smeared the bullet bases all the time. Removed the spru plate and went through my collection of center drills for my lathe. Found one that was a close match and touched the hole up so it was tapered all the way. Stoned the underside to remove any burrs caused by the drill and reassembled it. Next casting session the spru's were cleanly cut and no smearing. Don't think the actual size of the taper makes all that much difference but the part where it cuts should be sharp. If it ever gets dull can always redo it. Since I wear heavy welders gloves I also found out that downward pressure helps as well. When I get a new mold I check the underside of the spru plate for flatness. Smear a little prussian blue on it and slide it on a small surface plate. A lot of them I've found are not flat and stoning and rechecking on the surface plate will tell the tale. Maybe not right in the scheme of things but so far has worked for me and the flattened plate does not mark the cavity. Frank

[glockfan]

Wait a little bit longer before you swing the plate. Gives the center more time to harden.

ah!! i have the same problem than OP with my brand new accurate mold with bevel base.some are left with a ''ring'' or a lip-burr. thanks for the cue.i'm gonna wait a little more before swinging the sprue plate.

[T-Bird]

If you're getting a ring around the base of you're boolit, that may not have to do with moving too fast, if you are using too much pressure from your lead source ( I use ladle) that will cause rings at the boolit base. It pushes lead between the plate and the mold. If you are moving the sprue plate too quickly, there will be small holes where the sprue was cut. It won't be smooth. If I misunderstood what you were concerned with, forget this post.

[country gent]

Another way to set your pace and keep production up is cast with 2 mouds in rotation. whie one is cooling your filling the other this uses the time waiting for the sprue to set up for filling the other moud.

[glockfan]

ruled out the problem mentionned earlier about the small ''fins''' around the base , by waiting a little longer before swinging the sprue plate. no more of it, perfect boolits.