Inc0nsistent drop weights?

[MK1MICAH]

Hello
I am casting up some boolits from a Lee 457405 that has been modified to drop 459-ish rounds. using a lee 20lb bp melter set on #8 and WW for an alloy. I am getting an inconsistent weight reading prior to lubing. The weights range from 416.5 to 426.8. I have cast about 60 boolits yesterday and am at a loss as to what could be causing this issue.
Any help will be greatly appreciated, I am reluctant to hunt with these untill this issue is resolved.

[cbrick]

Possibly a mold temp issue. A cool mold will cast lighter and a properly &, uniformly heated mold will cast proper & uniform weight for that mold with that alloy. When you first start casting the mold isn't at proper casting temp and the bullets will be lighter, if you pause during casting your mold will cool and aluminum looses heat very quickly.

Also, is the mold closing completely, is there anything holding it open slightly? Are the bullets round?

Rick

[MK1MICAH]

not as round as I would like. .457-.458 on eather solid side, .459-.460 on the split.

[montana_charlie]

The weights range from 416.5 to 426.8. I have cast about 60 boolits yesterday and am at a loss as to what could be causing this issue.In order to cast at consistent weights, you must first make sure all of the preliminaries are covered.

The mould must be hot enough that there are no wrinkles in the bullet surface.
The venting must be adequate to allow the base corner to fill completely.
The alloy twmperature and mould temperature must be ballanced to the point where it takes about five seconds for your sprue to turn frosty.

Once those parameters are satisfied, it's just a matter of casting at a cadence which maintains the balance between mould temp and alloy temp.
Then you vary your pouring technique until you get perfect bases.

You should verify that the base is totally filled out when you cut the sprue. If the base corner is rounded at all, even if only in a portion of it's circle, discard that bullet.
The lead of the bullet and the iron (or aluminum) of the mould should look like a single flat surface. No dividing line should be visible.

If your temperature balance is maintained, and your base is perfect every time, the non-varying cadence will produce bullets that all weigh (nearly) the same amount.




I usually cast a hundred 550 grain bullets in a session. Any bad base goes directly back into the pot along with all sprues and overflow.
I cut the sprue with the mould inverted and laying on my palm ... right over the pot. The sprue and excess metal ends up in my hand, and falls into the pot when I rotate my wrist.

The one hundred I finish with will be culled ruthlessly for visual imperfections, but the weight range of the entire batch of 'keepers' will be about a half grain ... and the perfect base plays a large part in that result.
My bullets are smooth-sided paper patch bullets. If you have driving bands to watch, that makes even more corners to check for total fillout.

Drag your finger over a corner. If it feels uncomfortable, it is sharp and fully filled.
If it feels silky smooth, it is rounded - and metal is missing - and that bullet won't make weight.


Finally, if you are not using a dipper, you should try it.

CM

[dragonrider]

Be sure that your mold is properly closed, check the top and the bottom.

[runfiverun]

i'd like to hear more about the modification.....
10 grs is 2.5% btw.
the swing could be from the mold filling well and shiney boolits to too hot and frosted rounded boolits.

[prs]

With Lee moulds, this can happen if you inadvertantly let your fingers contact the spru cutter handle while pouring the mould. Close the mould making sure it is fully closed and alligned. Keep your fingers ONLY on the two main handles with only modest hand shake pressure to keep closed. After the pour, keep that same modest handshake pressure on the two main handles until the first color phase of the lead freezing has occured. Cut the spru as soon as the metal is well froozen, should be like sharp knife through butter.

prs

[knifemaker]

I have that same Lee 20# pot and if you have it set on 8, you may be running your pot too hot. I set mine between 4-5 and the melt is running at 700 degrees and goes up to 725 as the lead gets lower in the pot.
You can start out at #8 and when the lead is melted, I would turn the pot down to 5 as you start casting. I also pre-heat my molds on a ceramic hot plate that is used in labs and get consistant results on the fill out and weight.

[MK1MICAH]

In order to cast at consistent weights, you must first make sure all of the preliminaries are covered.

The mould must be hot enough that there are no wrinkles in the bullet surface.
The venting must be adequate to allow the base corner to fill completely.
The alloy twmperature and mould temperature must be ballanced to the point where it takes about five seconds for your sprue to turn frosty.

>check,check,check and check.

Once those parameters are satisfied, it's just a matter of casting at a cadence which maintains the balance between mould temp and alloy temp.
Then you vary your pouring technique until you get perfect bases.

>I do my absolute best to stay at a good speed

You should verify that the base is totally filled out when you cut the sprue. If the base corner is rounded at all, even if only in a portion of it's circle, discard that bullet.
The lead of the bullet and the iron (or aluminum) of the mould should look like a single flat surface. No dividing line should be visible.

> yes. all good here

If your temperature balance is maintained, and your base is perfect every time, the non-varying cadence will produce bullets that all weigh (nearly) the same amount.




I usually cast a hundred 550 grain bullets in a session. Any bad base goes directly back into the pot along with all sprues and overflow.
I cut the sprue with the mould inverted and laying on my palm ... right over the pot. The sprue and excess metal ends up in my hand, and falls into the pot when I rotate my wrist.

The one hundred I finish with will be culled ruthlessly for visual imperfections, but the weight range of the entire batch of 'keepers' will be about a half grain ... and the perfect base plays a large part in that result.
My bullets are smooth-sided paper patch bullets. If you have driving bands to watch, that makes even more corners to check for total fillout.

Drag your finger over a corner. If it feels uncomfortable, it is sharp and fully filled.
If it feels silky smooth, it is rounded - and metal is missing - and that bullet won't make weight.


Finally, if you are not using a dipper, you should try it.

> I guess Ill have to check into this. :groner:

CM

Thank you very much. Ill look into refining my processes to insure that I am not missing something.
-Micah

[MK1MICAH]

i'd like to hear more about the modification.....
10 grs is 2.5% btw.
the swing could be from the mold filling well and shiney boolits to too hot and frosted rounded boolits.

Yeah no worries whatever you want to know!

[MK1MICAH]

With Lee moulds, this can happen if you inadvertantly let your fingers contact the spru cutter handle while pouring the mould. Close the mould making sure it is fully closed and alligned. Keep your fingers ONLY on the two main handles with only modest hand shake pressure to keep closed. After the pour, keep that same modest handshake pressure on the two main handles until the first color phase of the lead freezing has occured. Cut the spru as soon as the metal is well froozen, should be like sharp knife through butter.

prs

Ok When I cast, I have a freaking death grip on the mould handles! so they should be loose in my hands?
:confused:

[MK1MICAH]

I have that same Lee 20# pot and if you have it set on 8, you may be running your pot too hot. I set mine between 4-5 and the melt is running at 700 degrees and goes up to 725 as the lead gets lower in the pot.
You can start out at #8 and when the lead is melted, I would turn the pot down to 5 as you start casting. I also pre-heat my molds on a ceramic hot plate that is used in labs and get consistant results on the fill out and weight.


Even If I am using WW? I thought it need to be hotter. I get spout freeze at anything less than 6 ?

[runfiverun]

lee settings are arbitrary 5 on one is 10 on another.
my first 20 lb pot gave me 620-f at full bore 10.
after a little adjustment on the points inside it would go to 900-f.
don't death grip the handles, just close them and hold them up to the light see if more pressure makes them close any more.
it won't.
just find a happy consistent rate, hold the mold handles enough you don't get fatigued.
watch the color of the boolits as they come from the mold.
turn down the heat on the pot as you get going.
and count silently to yourself after you fill the mold as the sprue set's up.
after counting off about 5 seconds you'll gain more of a rythmn as this will force you to wait.
the movements and filling and such will dictate a 3-4 fills per minute rate.
i fill my molds slide them out from under the pot and do the silent count then open and return the sprue to the pot.
then dump the boolits, close the mold and sprue plate [in deliberate smooth movements]
then slide the mold back into position line up the holes and fill the holes paying attention to how i am filling the mold [swirling or direct shooting into the cavity]
then start the routine and counting over again.
yep i get bored doing the same thing over and over and over.
but i don't have a bunch of culls or sprues to deal with.

[williamwaco]

I have that same Lee 20# pot and if you have it set on 8, you may be running your pot too hot. I set mine between 4-5 and the melt is running at 700 degrees and goes up to 725 as the lead gets lower in the pot.
You can start out at #8 and when the lead is melted, I would turn the pot down to 5 as you start casting. I also pre-heat my molds on a ceramic hot plate that is used in labs and get consistant results on the fill out and weight.

DITTo

8 is WAY too hot on my Lee 20#

.

[prs]

Ok When I cast, I have a freaking death grip on the mould handles! so they should be loose in my hands?
:confused:

Just a modest steady pressure, death grip not necessary. Man thing is not to get a grip on that spru handle if you are using a 6 cavity mould.

prs

[fredj338]

The bigger the bullet the greater the potential for weight variation. Some of this is casting/alloy temps, some is technique. I pressure cast, put the spout right onto the mold. This seems to give the most uniform result, but which ever way you cast, try for consistancy on every pour. If the bullets all look fine & you have 10gr variation, you probably have internal voids. For a 400gr/45, 2-3gr is casting/alloy temp normal IME.

[MK1MICAH]

Ok guys
I can get my hands on some plumbers stick lead free solder or 5050 what is the ratio? Im going to pick up 30 or so lbs around noon today. Anyone know what I should pick up 5050 or lead free? What is lead free anyway. Remember I am using the ol' LEE 20# BP furnace :confused:

[runfiverun]

lead free is 95% tin and usually some antimony/copper/silver or a combo of them.
not enough of any of them to matter.
the 50-50 is just that 50% tin and 50% lead.
tin is always the first number.
anytime i find any solder of any kind for cheap i get it, even if it's 30-70/20-80 body filler.
or 60-40 with flux solder.
i try to avoid acid core if possible but i won't pass on that either if it's 50 cents-$1.00 a roll,i just melt it down outside and far away.