30 cal bullet size all over the place

[acoilfld]

I am trying to cast 30 cal bullets with a IDEAL 311041 mold. It seems to be casting all over the place - +/- .003. The smallest it casts are .311, and the largest I got so far is .314. The mold is clean, and closed equally each time.
I have been casting pistol (.45) bullets for several years and BP round balls longer than that. Never had a problem like this. Is the small diameter (compared to .45) more temperature sensitive?
I can size them down - but that doesn't help with the fact that most (3/4) bases are to large for the gas check to fit on.
Of course I cast 2000 (in a single mold) before I started to size them :sad:

Any suggestions as to what could be the cause of this?

Thanks in advance for any ideas.


AC

[Bullshop]

"The mold is clean, and closed equally each time"
Well that eliminates almost everything I can think of accept that the blocks may be warping as they heat. Sometimes there are unseen inclusions in the block material that will cause them to warp as they heat then return as they cool. Same goes for rifle barrels that continue to walk the group as the barrel heats for no other apparent reason.
Try holding the mold up to a bright light while being held closed both when cold and hot.
Careful of your nose when its hot though!!! Dont ask !!!
BIC/BS

[Mk42gunner]

AC,
Sounds like one of the alignment pins may be protruding too far.

Are the bullets round? What I mean is what do they measure at the parting line and 90 degrees from it.

I had a similar problem with one of the group buy molds (314-120) from Lee; it would measure .314"X.322". Your mold is made of iron the one I had trouble with is aluminum. What I found was one of the alignment pins had swaged the aluminum just enough that the mold didn't close completely; it looked closed, but wasn't.

Oh yeah, mine would throw just enough round bullets at .314 to make me think it was operator error. I finally found it by smoking both mold faces completely and using it for about thirty minutes. I was so fed up I was getting ready to use a file to take the mold faces down a few thousandths; I even introduced the the mold to the old horseshoeing rasp.

Good luck

[acoilfld]

"The mold is clean, and closed equally each time"
Well that eliminates almost everything I can think of accept that the blocks may be warping as they heat. Sometimes there are unseen inclusions in the block material that will cause them to warp as they heat then return as they cool. Same goes for rifle barrels that continue to walk the group as the barrel heats for no other apparent reason.
Try holding the mold up to a bright light while being held closed both when cold and hot.
Careful of your nose when its hot though!!! Dont ask !!!
BIC/BS

When they are hot I can see a slight gap on the bottom (just checked). I tried leaving the screws that hold the blocks on the handles "loose"(in case they were binding)but it didn't make any difference. Top is tight.
When they are cold it is tight on top and bottom.
(sorry - my typing skills leave a a lot to be desired :|)

[acoilfld]

AC,
Sounds like one of the alignment pins may be protruding too far.
I will check that out - thanks

Are the bullets round? What I mean is what do they measure at the parting line and 90 degrees from it.
the large ones are oval - .311 ones are nice & round

I had a similar problem with one of the group buy molds (314-120) from Lee; it would measure .314"X.322". Your mold is made of iron the one I had trouble with is aluminum. What I found was one of the alignment pins had swaged the aluminum just enough that the mold didn't close completely; it looked closed, but wasn't.
This mold is made of brass - if that makes any difference. The pins appear tight.

Oh yeah, mine would throw just enough round bullets at .314 to make me think it was operator error. I finally found it by smoking both mold faces completely and using it for about thirty minutes. I was so fed up I was getting ready to use a file to take the mold faces down a few thousandths; I even introduced the the mold to the old horseshoeing rasp.

I will take a good look at the pins tomorrow, like yours, there are some really good bullets cast - and some ....




Thanks for the help

[acoilfld]

I cleaned it thoroughly and examined it very close.
The faces (or 1 of them are warped).
Anybody have any experience in matching up the faces again?
I am thinking of straightening out the surface with 600-800 grit paper on a flat surface, and using a bullet with some fine compound to ensure that the "hole" is even.
Any suggestions would be appreciated.

AC

[stephen perry]

After you are convinced your mold closes properly. Speed up your tempo. Instead of casting 200 bullets per hour go for 300 to 400. This will keep the mold at a hotter more consistent temp. rate. Shoot the ones you cast try this next time and compare bullet diameter. Should be closer to the same.

Stephen Perry
Angeles BR :brokenima

[mooman76]

Did you take them off the handles to make sure it wasn't the handles cause the warp? Seems to me it would be warped all the time if it is but I'm just a thin-in!

[doubs43]

Did you take them off the handles to make sure it wasn't the handles cause the warp? Seems to me it would be warped all the time if it is but I'm just a thin-in!

Good suggestion. I adapted a pair of Lee handles to a Saeco mold last week and had to drill out the pin holes in the handles. The first time I put the combination together, the front of the mold had separation. I then opened the pin holes more for a looser fit and the problem disappeared.

[Char-Gar]

What you are not telling us may be significant. You are not telling us..

1. How many cavities does the mold have?
2. What is the alloy?
3. What is the tempreture of the alloy?
3. Are you adding alloy as you cast?
5. What type of furnace are you using..i.e. bottom draw of ladle
6. What is you casting technique?

All of these are relevative to the human factor, which needs to be delt with before going to the mechanics of bullet molds. The fact that you are getting inconsistant casts makes me want to look at the human factor first. Mold can present all kind of problems, but usualy the problems are consistant and repeatable.

[Bret4207]

What Chargar said- need more info. You sure you have a BRASS IDEAL mould? Try a magnet on it and if it really is brass contact the Antique Reloading Tools Collectors website because you ahve a very rare mould.

Your problem could be pouring style, temp, mechanical... need more info.

[runfiverun]

if he has a brass ideal mold i'd like to see a picture of it.

[Bullshop]

I have an old Ideal mold that looks just like brass but a magnet will stick to it.
I think that the % of copper in the alloy must be higher than normal.
I think that mehanite the iron alloy used for mold blocks is a copper iron alloy with possibly some other metals.
Just my guess.
BIC/BS