Minie Ball question, possible defect?

[BottleBoss]

I purchased some 'reproduction' minie balls for my james river armoury model 1861 rifle recently. I won't mention the company who made them so as not to cause trouble. I have never bought them, or used them before but I have noticed that at the rear of the bullet where it dishes inward you can see a small chamber up in the bullet where it looks like it is not filled with lead on a lot of them. Perhaps this was a casting error? Are they safe to use like this? I'm in the learning phase on all of this so any help is appreciated.

 

[paulvallandigham]

Bubbles in cast bullets are common, so weigh the bullets to see how uniform they are in weight. If there is a more than 2% variance in total weight, I would send them back. Otherwise, shoot them.

They are not dangerous to shoot. You don't say if you have sized them down to your bore diameter. Unless they are within .002" of the bore diameter, you are not going to get best accuracy. Lube the grease grooves, but leave the base cavity clean.

 

[Trot]

Not dangerous but not the best for accuracy. I throw those ones back in the pot when I cast my own.

 

[BottleBoss]

Thank you all very much.

 

[Tumblernotch]

I purchased some 'reproduction' minie balls for my james river armoury model 1861 rifle recently. I won't mention the company who made them so as not to cause trouble. I have never bought them, or used them before but I have noticed that at the rear of the bullet where it dishes inward you can see a small chamber up in the bullet where it looks like it is not filled with lead on a lot of them. Perhaps this was a casting error? Are they safe to use like this? I'm in the learning phase on all of this so any help is appreciated.

They're safe, but if the void extends up into the bullet your accuracy will suffer. Weigh your bullets and throw out the light ones. I've had Minies with small voids both in the cavity and the nose that weighed OK (the voids were very small), but I still throw them out. My first inspection is visible. Any wrinkles or voids condemn them to the pot. What's left gets weighed. If light, there's an internal void somewhere and it gets pitched too.

 

[Viking78]

Hollow base bullets are rather difficult to cast. A trick is to keep pouring lead after the mould is filled ”“ this forces the air out of the cavity. Not much you can do about it if you purchase them though. :wink:

Split your bullets with a knife, and you'll see how the voids look like:

 

[Tumblernotch]

Hollow base bullets are rather difficult to cast. A trick is to keep pouring lead after the mould is filled ”“ this forces the air out of the cavity. Not much you can do about it if you purchase them though. :wink:

Split your bullets with a knife, and you'll see how the voids look like:

Yes, they can be hard. If you keep the mold hot and the lead as hot as possible (not red hot), the likelihood of voids occuring drop. Some people say that if your bullets are frosty your lead is too hot. In the case of Minies, to me, the frostier the better. If you tilt the mold a little when pouring you can usually avoid having voids form at the top of the cavity.

The problem with large caliber elongated bullets, especially those with a cavity is the fact that by the time you finish pouring, the lead at the bottom is beginning to cool a little. That's why I like to keep things as hot as possible. And, like you, I keep pouring even after the mold is topped off. And enlarging the sprue plate opening has helped me immensely.

Also, keeping the air vents in the mold blocks is very important. You have to get all air out.

And talking about hard, pouring .69 cal. Minies without voids is real fun!

 

[paulvallandigham]

Increasing the size of the hole in the cut-off plate, to allow MORE lead to enter the mold FASTER is the way to get the entire bullet formed before the lead at the bottom cools too quickly.

Also, you can put that base plug on a lathe, or in a drill press chuck, and reduce the diameter of the end that forms the cavity with the mold. That makes the "skirt" thicker", and the thicker the skirt is, the more lead it holds, and the hotter it stays during pouring. The thicker skirts are less likely to blow out or be damaged during both loading and firing. The soft lead use will allow the skirt to expand into the grooves, however,even when the skirt is thickened.

Even a small increase in thickness of as little as 1/64th of an inch is sufficient to "cure " casting problems, and problems with skirts blowing when fired.

 

[redwing]

The first thing you do is buy a very good set of mold blocks. :thumbsup:

 

[Tumblernotch]

I've actually turned a bigger base plug for one of my molds. Makes for a thinner skirt which allows you to use a very light charge for those 50 yard matches. Much more accurate, especially in a 1/48" twist match barrel. For hunting and longer ranch matches I use the factory plug.

 

[Tumblernotch]

The first thing you do is buy a very good set of mold blocks. :thumbsup:

I have some good molds. My .577 is a Lyman (the one I made a modified plug for) and my .69 (.685) is an old Ideal. They both cast very good Minies. I still have an aluminum .575 Lee which has an integral base plug, but it has worn so bad that it's no longer true. I may rebuild it one of these days when I have the time.