boolit casting problem

[Deputy Dog]

I am casting a 250 38/55 bullit with a lee mold Itry to sort them by weight in one grain incremints such as 249 to 250 the problem is I have five diffrent piles from 246.5 grns to 253 grns iam using a lyman #2 mix I cast around 75 and weigh them wityout turning the pot off or adding to the pot I cast again the bulk of bullits weigh about a grain more . anybody have a idea what i need to do to keep my weight closer.

[GP100man]

Cast hotter ! even if they frost a bit they`ll be more consistent .

Also your average is 250 & + or- 3% from that I`d call good.

But then again the less consistentcys we remove the better .

Maybe titen it to 1.5% & keep em seperate ,then shoot for groups & measure difference.

[williamwaco]

Your weight variation is well within normal. Don't worry about it.

I have two Lyman and the one Lee .375 bullet molds.

My most accurate bullet is a 220 grain Lyman mold customized for me by Eric Oehler.
The Lee mold is second best with average groupings around 1.5" at 100 yd.

I originally weighed the bullets in to one grain batches. I no longer do that. My bullets vary about 3 grains and I see no difference in group size.


Get some of those bullets loaded up and get to the range.
If you don't already have a load, start with 9 grains of Unique.


.

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[ShooterAZ]

Unless you are a very serious competition shooter...I would not worry about a grain or even 5 in a 250 gr boolit. If you are using a 6 cavity mold...each cavity is prob throwing a little bit different weight. I say just load em up and shoot them.

[canyon-ghost]

It's a fact that the lighter ones will have some air voids, maybe tiny ones but, they'll be there. I sort for medium weight through heavies and put the lightest back for repouring. I'd go 251 through 253 and see if I get a good 50% yield. If these are plinkers you can use some lighter ones but, I don't. I try to get from 1.7 grain to 2.7 grain weight variance on them.

Medium heavyweights are better. And I throw out a handful of the extreme heavweights too. I do shoot match style too.

Alloy consistency is another factor. I use wheelweight with maybe, only a little tin. Throwing in an ingot of linotype or some solder can have your alloy swinging back and forth in hardness and weight. Heavy is soft, hard is light. It'll run amok if not completely mixed and consistent.

[runfiverun]

good post ^^^^^^

[Gliden07]

Newbie question, Is that before or after sizing? After sizing that would make the weights a little more consistant wouldnt it?

[blackthorn]

Sizing changes shape/dimensions but not weight!

[1Shirt]

Cast hotter, establish a timed sequence, and I think you will see improvement.
1Shirt!

[Deputy Dog]

I was just wanting to get the best accuracy I could right now I have them weighed into four groups from 249 to254 in one grain incrments the majority are staying now betwin 249 and 252 I guess you were right on getting arythem and timing when casting . Is bullit weight more important on lite 22 projectilesso far inch and half at 50 yards is the best I can do with my lowall hornet tang sights.

[runfiverun]

weight sorting is king of the pile with the little calibers.
i cull by eye ruthlessly then weight sort and separate into tenths of grain piles.
all the light ones and overly heavy ones go back to the pot.
i keep only ones that are within a half grain of my median.
i size lube check and then lube again then weight sort again and put those into thier respective cups with the weights marked on the lids.
i usually end up with 57.3/57.4/57.5/57.6 telling me my 2 cav mold has one side slightly heavier than the other.
i shoot the 4's and 5's in my 223's as they make up the bulk of the castings by far, i keep the 3's for the 220 swift and the 6's for the 22-250.

yeah it's a lot of work but it really pays off when you get up over 2400 fps.

[41mag]

Just a couple of questions,

What type pot are you using?

Are you using a thermometer in it while pouring?

Reason I ask is that I found when using my Lee 6 cavity molds, if I kept the alloy in a specific temp range it was MUCH easier to keep the weights closer. With the alloy level dropping in a Lee pot it will get hotter as it gets lower, which results in your mold getting hotter which results in your bullets weighing different than when you start out.

I started out with simply setting the dial to around 4.5 which was enough to get my straight WW alloy melted and pouring good. Once I got through with a batch, like you I had plenty which were heavier than others. Then I picked up a thread on temps, and weights, got me a thermometer from SwedeNelson, as well as the one for the mold. After drilling my mold and keeping track of both the pot and mold I got my batches down to within about 5grs max. I also got me a cheap clock to set my timing with and with that and monitoring the alloy temp I could easily keep around the same with out using the mold thermometer.

Then I added what I feel has been the best thing since sliced bread, one of the PID units. It might be a bit of excess equipment, but it sure is nice to set the temp and then simply got down to pouring. It keeps things pretty even all the way down to the bottom of the pot.

Here is the thread I referred to above,
Analysis of cast boolit weight variences (http://www.castboolits.gunloads.com/showthread.php?t=120938)

While far from being "LAB QUALITY" testing it does outline some perspective of what you can have.

Hope this helps,

[runfiverun]

i use the magma 40 lb pot with two pour spouts on it.
the temp dial is adjustable so i set it with my thermometer.
i start the mold out hot [rcbs 055-sp] slowly pour to cool it to the right mold temp, then shift the castings over to a water bucket.
and strive to keep the mold in a constant temp zone and a consistent pace.
my 22 alloy is 4/6/90.
i pour and open the mold as the sprue puddle is solidifying,dump close and fill.
it takes about as long to read as do.
alloy temp is in the 700 range.
if i do 5 lbs of alloy it's a hustle and a pile of boolits.