Cast Bullet Size

[dsh1106]

I need some help with my casting .....


I have my alloy mixed @
Pb = 92.8%
Sb = 3.2%
Sn = 4.0%

I run my pot temperature @ the minimum to get a complete fill on my boolits.

Most of my boolits can be sized after casting but some don't drop large enough to size. Is the anything with alloy temperature that will increase the diameter, or am stuck with the product of the mold?

Scott

[bedbugbilly]

There are those much wiser than I when it comes to alloys, etc. - I'm pretty "low tech" - but before I started to get too worried about it - how many are actually undersize per say a count of 100? How much undersize are they?

What mold are you using? Is it a single cavity, double cavity or multi cavity? Is it possible that one cavity is dropping them smaller than the others? What caliber?

Example: I have several molds that I use for my 8mm - the majority of the time, they will drop at around .324 - .325 - bear in mind I only use "range lead". But, at times I do get some that drop at .323. I run all of them through my .323 sizer and the ones that drop undersize from normal glide through the sizer and shoot just fine and I've never had a problem with leading. The same goes for some of the molds (and I have quite a few of them) that I use for 38/357 & 9mm. I have several old Lyman molds for 38s that are double cavity and on cavity drops smaller than the other - same dipper out of the pot, same temp., etc.

Personally, I would do a little experimenting - cast at your normal temperature - bump the temp up a little and cast some - then bump it up a tad more and cast some. Then check what the results are as far as sizes that they drop.

Again - there are those on here who are more scientific than I - for fifty some years I have cast from a pot with a dipper on a propane hotplate so my variables as far as temperature are much more than with a pot with a thermostat - and my alloys vary according to what batch of range lead I'm using.

Good luck!

[JonB_in_Glencoe]

here is an interesting thread about temperature...that'd be mold temperature.

http://castboolits.gunloads.com/showthread.php?67537-Relationship-of-casting-temperature-to-boolit-size

I'm not sure how much size increase you are looking for?
OR what caliber ?
because both[heat and caliber] will have a factor in how much size increase you'll see by casting hotter.
with that said, I doubt you'll be able to increase boolit size by as much as .001

I had a Lyman 266469 2 cav mold.
It'd cast a .268 boolit with my standard casting procedures, using 94-3-3 alloy I typically use for rifle. I wanted the boolit to measure .269
I tried casting hotter, as well as trying other alloys, like COWW, and also range scrap, as well as Lino.
I couldn't achieve any measurable size increase.
I then "beagled" the mold with foil tape, I then got a oblong boolit measuring .268 by .270
I sized those down to .269 and I'd get a shootable boolit, but never got the accuracy I hoped for.

[runfiverun]

I find it easier to modify the mold.
look up lapping.

[dsh1106]

Here is some data to fill in the blanks ...

SC Mold # 338320 - bullets are dropping .3395 - .3405

I would like to size the bullets at .340 diameter. Running them through the .340 die I get "clean-up" only at the parting lines.

I just finished running 100 a bullets, started my pot temperature at ~ 650 and ran a few moved to ~ 700 then ~ 750 then ~ 800 then ~850. All the boolits measure the same size, some are frosted and some are not frosted. I did have to slow down once I hit ~ 750 because the mold was holding too much heat. I started with the mold temperature at ~ 350.

[dsh1106]

I have, at least on this run of boolits, come to the conclusion that heat didn't affect the size. I can tell you it does affect the weight.

On these 100 boolits the weights fluctuated from 202.4 grs to 205.7 grs.
Here's the distribution
202.4 - 2 pcs
202.7 - 4 pcs
202.8 - 1 pc
202.9 - 3 pcs
203.0 - 1 pc
203.1 - 1 pc
203.2 - 2 pcs
203.3 - 8 pcs
203.4 - 5 pcs
203.5 - 4 pcs
203.6 - 3 pcs
203.7 - 7 pcs
203.8 - 9 pcs
203.9 - 5 pcs
204.0 - 5 pcs
204.1 - 3 pcs
204.2 - 3 pcs
204.3 - 2 pcs
204.4 - 3 pcs
204.5 - 4 pcs
204.6 - 2 pcs
204.7 - 8 pcs
204.8 - 1 pc
204.9 - 1 pc
205.0 - 5 pcs
205.1 - 5 pcs
205.2 - 1 pc
205.3 - 2 pcs
205.4 - 2 pcs
205.7 - 1 pc

[Oklahoma Rebel]

do they still shoot good in the gun you are casting for?

[dsh1106]

do they still shoot good in the gun you are casting for?

These group Ok ....
@ 50 yards a 5 shot group measures just over 5/8"

The 338089 sized at .340 (complete clean up), shot at the same distance, group just under 1/2"

Scott

[JonB_in_Glencoe]

Here is some data to fill in the blanks ...
SC Mold # 338320 - bullets are dropping .3395 - .3405
I would like to size the bullets at .340 diameter. Running them through the .340 die I get "clean-up" only at the parting lines.

...SNIP
Have you measured your groove dia. ?
If it's under .340 ...once you install a GC and "clean up" with the .340 size die, I think you'd be golden. That's about ideal, the less sizing before loading, the better for Rifle ammo.

My new 6.5mm NOE mold, that I bought to replace the Lyman (I mentioned above as an example) drops a boolit .0005 over groove dia of my rifle and my size die just "cleans up" the boolit while crimping the GC and lubing it.

[dsh1106]

Have you measured your groove dia. ?
If it's under .340 ...once you install a GC and "clean up" with the .340 size die, I think you'd be golden. That's about ideal, the less sizing before loading, the better for Rifle ammo.

My new 6.5mm NOE mold, that I bought to replace the Lyman (I mentioned above as an example) drops a boolit .0005 over groove dia of my rifle and my size die just "cleans up" the boolit while crimping the GC and lubing it.

My groove diameter is .3387 - .3390, which is why I was trying to size the boolits to .340

Scott