casting 7.62x39 undersize. I want .312 getting .309-.310

[crackerjack57]

Hello all.

I'm one of the Newb's that has some questions. Its probably been answered somewhere in this forum but due to the overwhelming amount of fantastic info, I cant find it.

I bought a whole load of casting supplies from a lee pot with the little spout out the bottom to a lee C312-155-2R mold. I'm casting for my 7.62x39 sks and this mold is made for this type of bullet that should feed well into the sks.

I bought a bunch of scrap wheel weights and melted so that's my lead supply. I am casting some really nice bullets and the gas checks fit perfectly but I slugged my barrel and it comes out to .311. These dies are dropping out as .309- .310 is there any reason for this? I am quenching the bullets as they drop out of the mold but have not tried air cooling them yet. any suggestions to get these up to the .312 at least? is it something I'm doing or is it a faulty block. :popcorn:http://castboolits.gunloads.com/images/smilies/popcorn.gif

As me being the New'b its most likely something on my end.

another quick question is that when looking at the process of fitting even if the bullet were .312 diameter into the properly sized case, the case seems to squeeze the neck of the bullet to a smaller diameter. am i right in this or does the case expand to accept the bullet?

Any one reloading steel cases??

thanx

[runfiverun]

about the only way to get them bigger is to use a harder alloy,or beagle the mold which will get them one sideed larger,or a combination.
unless you want to do some mold lapping which will gain you about .002 before you lose definition.
or you could try pressure pouring from the spout into the mold.
i have a non vented ideal mold intended for the 32 win which responds to this very well.[and allows me to use the boolits in my 8 mauser]

on the neck-boolit thing.
both can happen the boolit will force it's way into the neck of the case but the case will/can then squeeze it down.
most guy's get around this by opening the neck enough to give about .001-.002 neck tension.
by using a larger expander ball or a lyman/lee m-die.

[Larry Gibson]

If your Lee pot is the 20# then open the spout adjustment up to get the alloy out quicker. Cast at 725 degrees. Makes sure a good sprue is formed or runs off each cavity. Add 2% tin to your COWWs. Let them harden/age for 7-10 days before use. I'd bet on the as cast being close to .312+.

Larry Gibson

[turtlezx]

if your using lee dies they come with 2 dif size expanders 308 &310
make sure your usin the 310