bullets get heavier as casting proceeds.

[Dumasron]

The pot is a good one, and keeps very constant temperature. The dies are Lyman 457658, and on the box it says this should make a 480 gr. bullet. The melt is comprised of range salvage plus 5lbs of pure lead from Rotometals. Over the course of casting 45 bullets, the weight of the bullets rose incrementally from 494 to 501. I weighted every 5th bullet in order to establish this.

Just like everybody else, I would like to make a big batch of bullets within one grain of each other. Anyone know what is happening here and how to control it?
Thanks
Ron

[bigted]

there could be a few things going on but im bettin that it is the thing that has bit me more often then not.

have you measured the boolits for out of round? i found with my casting that the longer i cast i get tired and my grip is softer as time goes by. when i purchased the baco [buffalo arms] locking handles ... this all went away. now i cast boolits that are usually within 2 or 3 tenths of a grain to each other and all are perfect in roundness. also i find that if i coat the bearing portion of my mold each time [casting session] with a mold release agent ... the molds work with little effort.

there are a couple other things that may be happening such as do you flux your metal each time and when there is dross beginning to gather either on the dipper or on top of the melt.

your range lead/metal may have a bunch of goodies that will screw the pooch where melting and stability are concerned. may have to throw away that range metal and go with a known metal mix that is compatible with what you desire them to do.

[DangerousDrummer]

It is said that differences in lead temperature will affect the weight also. I am lucky that I have a lathe so I bring all the weights to the same target weight by removing material with my center drill from the base until they match. While this is slow and time consuming, it doesn't matter if I am going to compete or build a long range hunting round. For plinking, who cares?

I am building some bullets for my Mosin Sport that will take me all week to complete, but if I wanted fast, I would just buy a spam can of crappy bullets.

[bigted]

given a good mold in good shape with no lead buildup on the faces there should be no reason to not cast perfect boolits. dinkin with your boolits after they are cast is a waste of time and needless for perfect boolits. maybe the time would be better spent on trying to get a procedure down for casting those perfect boolits.

if on the other hand you are getting the boolits that you want from doodling with them and there would be no other option for getting them just so then that is another story ... but to lathe them to make em perfect weight to each other is taking a long road to get something that should be viable with just the casting procedure.

i have cast with Lyman as well as RCBS handles and find that my old man grip suffers the longer i cast. allowing both lead build up on the faces as well as inconsistent weight and outta round boolits ...soooo ... i purchased a set of handles from BACO and this ended my casting problems completely. they are a set of handles that close similar to a set of vice grips. the mold gets the exact same pressure on the blocks each and every time and cast those perfect boolits that i refer to ... considering the mold is the correct heat and the melt is the same. may just be the best 75 dollars you ever spent as far as casting goes.

good luck with your casting chores.

[montana_charlie]

I am lucky that I have a lathe so I bring all the weights to the same target weight by removing material with my center drill from the base until they match.
If the bullets are physically identical, but differ enough in weight that you need to modify them, there is something wrong with your casting method.

But ... if you remove metal from the bases of those otherwise identical bullets you are changing the 'balance' of those bullets ... moving the center of gravity forward.
Then, if you remove different amounts of metal because they were cast at differing weights, you are unbalancing them in varying amounts, as well.

If you will cast bullets with an unvarying tempo, they will come out with a very small weight spread.

CM

[MT Chambers]

Bottom pour or ladle?

[williamwaco]

I suspect something clinging to the face of the block.

[Lead pot]

There are a couple things going on that is changing the weight if it is the same batch you first started with this pot full.
#1 your mould came up to temperature and filling properly.
#2 You getting a lead build up under the sprue plate from opening it before the alloy is set. and if you're casting with a loose sprue plate and getting a lead smear under the plate it is raising the plate and in sense the bullet is getting longer because of the raised sprue plate. It doesn't take much to get the weight variances you're getting.
Make sure your mould face is free of lead specks.
WIth the proper casting routine your bullet should not vary a total of 1/2 grain.
The next time you cast and your mould is up to temperature after casting for a while, cut the sprue and keep the mould block shut. Take a sharp box cutter blade and hold it with a pliers and push it over the block and cut the high lead off the mould base and weigh the shavings. You might get a surprise.

[DangerousDrummer]

I make a pin hole in the bullet base so that they can be placed on a pin tray for powder coating, not because they are imperfect. I need to modify them but try not to change the weight so I weigh them after each stage of the powder coat preparation. I also resize before and after powder coating. Powder coating is still cheaper than gas checks and ya gotta admit, they are certainly pretty.

[dave roelle]

If your ladle pouring ----dig deep into the center of the melt-------more consistent temperature and it keeps the melt agitated an aid in uniform pot temperatures

Dave

[montana_charlie]

I make a pin hole in the bullet base so that they can be placed on a pin tray for powder coating, not because they are imperfect.
Oh!
So, you didn't actually say, "I am lucky that I have a lathe so I bring all the weights to the same target weight by removing material with my center drill from the base until they match."

My mistake ...

[DangerousDrummer]

Sorry Charlie, did not mean to offend. I am just a newbie practicing while I wait for my CPA 45-90. I have invested about 16 hours to build these 50 completed cartridges, and since they come from a Lee mold I am sure they are not as good as what you cast. And yes I did intend to move the center of gravity forward, based only on the fact that a 7/8 shotgun slug seems to be more accurate than a 1 oz slug. (what is called the "shuttlecock" effect)

But these are now within .5 grain of each other in weight. Each one carefully inspected and culled for the least imperfection. They are powder coated and then re-quenched, then culled again at loading.

94896

But they shoot like this...

94897

Using this 1943 Mosin Nagant that I have slightly modified.

94898

But this is all just practice while I wait for my CPA 45-90 and brass. Meanwhile I will not reply to future posts, I will leave that to the experts.

[Frank Savage]

Two more things not mentioned yet:
-Alloy consistency. You need to stirr the melt frequently, about every time you return the laddle back to melt or every time you wait for setting of the bullet you just cast. Maybe every second bullet, but more frequent makes better. Otherways the melt stratifies, with the lead in the bottom and the more legured part with most of the tin and antimony on top. So your first bullets are not only lighter, but also harder if using laddle pour.
You need also the top covered by sawdust or wooden ashes, to prevent oxidation. The tin and antimony oxidizes a bit faster than lead and creates the dark grey mess on top. Also, this mess is porous and attract mainly the tin, which stratifies from the melt.
-If you use bottom pour, the lead alone has quite high surface tension and tends to stay away from the mold surfaces. You can try it, given the same temp conditions, the mold throws a bit smaller and less consistent with pure lead than it does with tint in alloy. Also, no matter how accurate is the PID of the pot, with noticeably lower level of melt in the pot, the pour nozzle gets a bit more hot, so you get a bit more hotter alloy into mold, then hotter (and bigger mold) and longer set-time-as well as bigger volume of unset alloy, which sucks more alloy from the blop on top of the sprue plate. All this resulting in heavier bullet.

Seems to me that with bullets over 400-430 grs or any weight, but with cal:lenght ratio greater than 1:3, the technique and timing is surprisingly more important. You can hog out dozen over dozen 220 grs 45 cal SWC´s from sixbanger and all ranging from good to perfect- But with heavies, or long beasts, you must realy pay attention to details-or not, but every time always the same way. And nurse every bullet.

[bigted]

seems we lost the OP.