What the floss?

[Burnt Fingers]

Ok,

I'll be the first to admit I haven't cast a lot of rifle boolits. But I've never had a problem till yesterday.

I got the Lee .30 cal 230 gr boolit mold for the .300 BO.

I cleaned up the mold, it's free of any grease or oil. I went out to cast some yesterday and must have cast 300 with the bottom pour. Never got a usable boolit. They all have swirls in them. I switch to a ladle and now I'm getting about 70% usable boolits.

I tried temps from 700° to 800°, the mold is smoking hot. I can cast with the ladle and get two good boolits, try the bottom pour and swirls.

It's obvious that the lead seems to be splashing and cooling when using the bottom pour. I really need to use the bottom pour because the only way I can ladle pour is to stand up and that doesn't help my back at all.

Any ideas?

[Sig556r]

I use Lee bottom pour to cast that mold a tad less than 700F.
I limit the spout just enough for a continuous flow, too much & it'll splash as you mentioned.
I use another mold or 2 alternately to allow mold too cool down while releasing another.
Works for me so far. BTW, I smoke even my aluminum molds.
good luck.

[Oily]

Have you smoked the cavities?

[Muddydogs]

Don't smoke the mold, its just not needed plus it doesn't sound like your having issues with bullet releasing from the mold your issue is more a temp or flow issue. Are you sure your thermometer is working correctly? Might also try and adjust the flow from the pot, I find when I get lines or swirls I need to decrease the flow just a tad and move the mold closer to the pots spout.

[JonB_in_Glencoe]

Long skinny boolits are some of the most difficult to cast.
Each mold just needs specific things.
...You just have to try different techniques:
Fast flow, slow flow, high alloy temp, low alloy temp, preheat mold to hotter temperature.
Try pressure cast ...or try Different distances between spout and sprue plate.

Lastly, mold modification:
Maybe the sprue hole needs to be enlarged?
Maybe clean out Venting lines or add new venting on top.

[country gent]

Have you tried pressure pouring? Seat the sprue plate onto the spout snug and fill lower mould and hand holding pot valve together to form sprue. This may help as angling the mould a little one way or the other. Some moulds can be tricky to get to cast well and some need a break in period. On a long heavy for caliber bullet I try for the fastest fill possible with the biggest sprue I can pour. Get the molten metal in before it starts to solidify. Swirls and not wrinkles or voids your probably close. The ladle is probably filling the mould faster

[jonp]

I tried everything with that mold for a 300BO with my Lee Bottom Pour. Pressure pour seemed to work the best as country gent suggested but I still never get more than 75% or so usable.

[Dan Cash]

Mould not properly vented and/or insufficient tin in alloy.

[454PB]

Another thought.....the spout on the Lee bottom pour pots can build up a coating of "crud", which reduces diameter and increases the velocity of the flow when the pot is full, and decreases the velocity as the pot runs low. I use a dental pick with a point about an inch long to clear out the nozzle every 100 casts or so. Insert the pick as the valve is being held open, then run it up and down a few times. It only takes 10 seconds to do, and I let the flowing lead deposit below the nozzle and then pitch it back in the pot.

[popper]

Use a fine file to take the sharp edge off the top of the blocks around the cavities. Make sure vent lines at the cavities are clear. Alloy ~ 725F. Adjust the pot stem to get a good steady flow of alloy. Dribbling or sporadic pour gives wrinkles. I removed the adjusting screw and put a small tap wrench on the valve stem. Adjust so it opens a good stream with the handle all the way up. Splashing indicated you're not pouring straight into the hole and possibly the spout is a long ways from the plate. Mine is ~1/2-3/4" from the plate. Too big a puddle on the plate cools fast and tends to clog the hole. Too fast a pour won't let the air escape. Practice pouring and you'll get it. Pressure pouring works but my arm get real tired holding the mould against the spiggot.

[longbow]

I'd suspect that the lead isn't getting in fast enough and possibly as mentioned already that the mould is not hot enough and/or alloy is not hot enough.

An easy thing to try is to loosen the sprue plate so it almost swings on it's own. If the tops of the mould blocks are really flat and true the sprue plate can restrict air escape so loosening it a bit often works... or it has for me anyway.

Another trick is to use a diamond hone or similar (very fine) to put a very small 45 degree bevel (each side) at the top parting line of the mould blocks ~ under the sprue plate... and I mean very small! Just barely break the sharp edges at the tops of the blocks. That will allow venting as well. I've done this with a couple of Mihec moulds and it has worked well especially when bases don't fill out well. Just a bit of extra venting at the top helps.

I wouldn't enlarge the sprue hole until trying hotter mould and/or alloy and loosening the sprue plate (might not be so easy on a Lee mould) or bevelling the tops of the blocks. I have found that my NOE aluminum moulds and my Mihec and Accurate brass moulds like to be run really hot to cast well. I have not found that with my Lee moulds but as JonB_in_Glencoe said, long skinny boolits might require a somewhat different technique or mould tweak.

Also, since the ladle is working better than bottom pour you might want to clean out the bottom pour nozzle as already mentioned. I find for large boolits and shotgun slugs of 400 grs. or more that ladle pouring works better than a bottom pour pot for me. I can get more lead in faster but these 230 gr. .30's shouldn't be an issue that way if every thing else is working well.

Longbow

[Burnt Fingers]

I'm using an RCBS PM II pot.

Plenty of tin.

Mold has been deburred and smoothed. Bevel applied to top of blocks.

Pressure pouring causes the same problem.

What solved it? Smoking the mold. I smoked it and it started pouring perfect boolits.

[Alferd Packer]

Ok,

I'll be the first to admit I haven't cast a lot of rifle boolits. But I've never had a problem till yesterday.

I got the Lee .30 cal 230 gr boolit mold for the .300 BO.

I cleaned up the mold, it's free of any grease or oil. I went out to cast some yesterday and must have cast 300 with the bottom pour. Never got a usable boolit. They all have swirls in them. I switch to a ladle and now I'm getting about 70% usable boolits.

I tried temps from 700° to 800°, the mold is smoking hot. I can cast with the ladle and get two good boolits, try the bottom pour and swirls.

It's obvious that the lead seems to be splashing and cooling when using the bottom pour. I really need to use the bottom pour because the only way I can ladle pour is to stand up and that doesn't help my back at all.

Any ideas?
I found that instead of letting the lead flow directly into the sprue hole that just a little to one side of the sprue hole and make a bank shot of the stream into the hole makes a difference .
First reduce the flow a little and then try it.
It takes some practice but I read of this technique years ago in a Lyman article talking about using a bottom pour pot.
This got rid of the swirl marks in cast bullets.
It takes a little practice but first reduce the flow with the adjustment screw.
You can't do it freehand.
It seems slower and it is, but not much and it works for me.
Good Luck.

[popper]

Smoking keeps the alloy hot longer and AIDS venting. Suspect a vent problem, probably go away with use.

[dtknowles]

I agree with not letting the stream from the bottom pour go straight down the hole. Cast faster and leave a bigger sprue. Let it only cool enough for a clean cut. The lead might be hot enough but the mold isn't.

Tim

[44Blam]

You gotta smoke that mold like a Rastafarian!

But seriously, I smoke my molds to the point that you can see the carbon and once my molds start casting good boolits - as long as the base looks good 99.9% chance it is a perfect boolit.