Minie weight consistancy

[SwanShot]

I have been busting em trying to get this right. We are talking about 58 cal Minies. I have two molds. The 500 grn Lee aluminum, and the 530 grn Lyman steel.
I have been trying lots of different tempts for mold and melt, using pure lead, and got nowhere near a consistent weight. Variation was around 10grns.
Today I tried adding tin to the mix at about 4%. That has helped with more consistent weights, but the very best I can get is a variation of around 5 grns, with the odd one still outside that range.

I am using a lee bottom pour 10 lb pot, but have also tried using a dipper from a cast iron pot on a camp stove, for even worse results. I have melted all the lead I have (about 40 lbs) in the cast iron pot, and fluxed it with both sawdust and wax, then ingoted it to use in the lee pot, at which I added the tin in the form of 50/50 solder, the only way I could get tin. And yes I fluxed again with sawdust after I added the tin/ solder.

I have fluxed with wax, and I have fluxed with sawdust, and with with charcoal. I have fluxed the same melt with all of the above.
So tell me straight, is 5 to 7 grns the best I'm ever gonna do??
I've been told that I cannot harden my alloy because I won't get the skirt expansion if I do. This is a 1853 3 band Euro arms Enfield repro.
C'mon guys, I need help here.

Using the 5 grn weight variation I'm getting 3 inch groups at 50 yrds off a bench, if we ignore the odd flyers.

 

[F.G. Ford]

Hello Swanshot
At 50 yds. from a bench you should have all bullets touching, if your trigger pull is decent, and you sights well matched.
Are your bullets sized and lubbed to less than .002" clearence to bore diameter.,
Are you damp swabbing between shots?
Unless you are pouring from a constant head weight of lead, it will be very hard to improve on 5 grains variance, after all that is only 1%.
Even bench shooters weigh each bullet, and sort them in groups.
I hope this helps.
Fred

 

[SwanShot]

Getting a sizing die is the next move
:thumbsup: I reckon the best bet would to swage em up, then down again in a lube die. I'm only talkin 5 thou max, not real big stuff, and the minies are very soft, so shouldn't be a problem.
I just wanted to ensure that I didn't miss anything in the casting.
I have to admit that my biggest problem lies in the fact that I have loaded and shot centerfire rifles for years, with expensive jacketed projectiles of course, and I just don't know what to expect of a black powder

 

[Rifleman1776]

A minie should be soft so the skirt expands to fill the rifling on a consistent basis. Adding hardening materials, IMHO, is just ruining your lead.
Inconsistent weight is usually an indicator of casting at too low a temp causing wrinkles and bubbles. Crank up to about 750 degrees (F) and try again with pure lead.
BTW, both Lee and Lyman moulds should give you excellent results. Unlikely those are at fault.

 

[curator]

The mould and base pin need to be HOT, as well as the alloy. I never add more then 1% tin to pure lead for minies. 1/2% usually works just fine for sharp castings without any hardening. With the Lyman mould, I put the base pin on the hot-plate burner to keep it hot when I remove it to drop out the bullet. The Lee mould is easier to use (lighter and comes up to temperature faster) but cools off quickly. A consistent casting speed will allow you to select a temperature that gives the best results. With the aluminum moulds I crank up the lead pot to about 800-850 degrees. The Lyman can be cast from at a lower temperature once it warms up but the base pin needs to be kept warm between pours or a void will form just above it in the bullet. This may be the source of your weight variation.It takes some practice to get good cast minie bullets. You have to do your first ones first. Keep turning up the temperature until you find what works with your equipment. As long as you don't go over 950 degrees you won't create "lead fumes" but don't neglect good ventilation regardless.

 

[Bob E]

I use pure lead without any alloy.5 to 10g variation is about normal. I used to weigh with a digital scale, decided that it didnt make much difference so now I simply visually inspect each bullet and remelt the defective ones.
One hole groups at 50 yds are certainly possible with the right powder charge. Having the lock properly tuned to a 3or4 # trigger pull helps a lot. A heavy trigger can cause a right hander to shoot right by a couple of inches.
In my opinion minie ball guns are easier to master because there are fewer variables to master. Please forgive me fo being overly longwinded. Cheers! Bob E

 

[SwanShot]

That's not long winded mate. Now give me a sixpack and a subject and I'll show you long winded :haha: :yakyak:
Thanks for the advice.

 

[Greenjoytj]

Try cutting up a couple of the lighter cast bullets. I suspect you will find a void inside that looks like an air bubble.
I could not get consistent weight in my round ball casting until I started using the steel Lyman moulds the Lee moulds lost heat too fast. The next trick was to keep the lead hotter like over 100 degrees above the lead normal melt point use a thermometer.
Use an Iron ladle my RCBS aluminum ladle lost too much heat. The most important trick was to just keep pouring lead into the mould long after its filled the purpose is to keep liquid lead available at the inlet so as the lead in the base of the bullet cools and contracts it can pull in more liquid lead. This continuous pour method solved my problem with getting a void bubble in the balls. The void bubble that I use to get were some times almost as large as a grain of rice no wonder I couldn't get consistent weights.

 

[nkbj]

On some minie designs the air ends up putting a void at the top of the pin. And sometimes you can overcome that by very high temperature and modification to the pouring technique.

 

[SwanShot]

On some minie designs the air ends up putting a void at the top of the pin. And sometimes you can overcome that by very high temperature and modification to the pouring technique.

Now this sounds right. Thank you Goodcheer

 

[SwanShot]

Try cutting up a couple of the lighter cast bullets. I suspect you will find a void inside that looks like an air bubble.
I could not get consistent weight in my round ball casting until I started using the steel Lyman moulds the Lee moulds lost heat too fast. The next trick was to keep the lead hotter like over 100 degrees above the lead normal melt point use a thermometer.
Use an Iron ladle my RCBS aluminum ladle lost too much heat. The most important trick was to just keep pouring lead into the mould long after its filled the purpose is to keep liquid lead available at the inlet so as the lead in the base of the bullet cools and contracts it can pull in more liquid lead. This continuous pour method solved my problem with getting a void bubble in the balls. The void bubble that I use to get were some times almost as large as a grain of rice no wonder I couldn't get consistent weights.

Thanks Greenjoy, I'll give it a try.
I'm gonna get this

 

[George T.]

I have to admit that I gave up on the Mimie's a while back and shoot 570 PRB's. It was not so much that I could not get them cast well I just could not get the same level of accuracy.

That being said I really do bot know what % weight delta is acceptable. It sure would not take many wrinkles or small voids to weigh 10 grains.

Long story short! I'm not much help , but the pure lead is the way to go because the skirt needs to expand to grab the rifeling. Good Luck! Geo. T.

 

[Pigman]

I was having some problems with accuracy.

Another shooter showed me that I was not seating the minie hard enough.

When you ram the minie throw the ramrod down 3 or 4 times and listen each time.

When the minie is fully seates the sound will change from a thud to a ding.

This made a difference for me.

THanks,
Foster From Flint

 

[Idaho Ron]

In my opinion your variance is more than likely due to poor mould fill out. With large bullets you need a bit of tin which you have. You need a lot of heat. and you need to pick up the pace to get that mould hot and keep it hot. Bottom pour is the worst way to get big bullets to come out nice. The ladle is the only way. Draw it from the bottom to keep it stirred up. Don't let it cool down unless the spru takes forever to become solid. I think you need to heat it up and pick up the pace. Ron