Wanting help... Lee 6-cav .356 RN

[dfwbiofuels]

Good afternoon y'all.

I've got a 9mm 6-cav Lee mould and I'm not over the moon about it so far. Of the 6 boolits it can cast, 2 or 3 of the 6 cavities throw boolits with small feathers at the base.

When I cut the sprue, I can see a small amount of lead. Its very thin. Its outside the perimeter of the mould, between the block and the sprue. When they drop, the bullets don't have a cleanly defined base.

What do I do to fix this?

[lesharris]

Welcome
A few more items would be usefull to help with the problem.
Is the mold new or used ?
Has the mold been Leemented ? [check in stickies for this]
What alloy are you using?
Bottom pouring or ladle casting ?
Pot temperature ?
All these items effect end result.
A quick quess sounds like the mold blocks are not closed all the way when you are pouring.That will cause the finning.
The base issue being not square or filled out can be that some lead has built up on top of the blocks. 2 things cause this.1cutting the sprue before it is solid or2
The sprue plate needs to be tightened down slightly.
When you close the blocks the sprue plate should be open.After the blocks close tightly then the sprue plate gets closed.
You can check the mold when it is cold.
Close the mold and hold it up to a light and see if any light shows where the mold blocks come together.
Then close the sprue plate and check for light[space]there also.
Hope this gets you on the right start.
Les.

[dfwbiofuels]

Thanks Les.

The mold is new.

I have looked into the leementing process. Typically used as a remedy for boolits that won't drop out of the mold? I'm referring to the process of spinning a cast boolit with abrasive paste. No I haven't done this yet because the molds drop bullets okay with a light tap.

I'm using a 20lb Lee pot, bottom pouring.

I don't have a pot gauge for temp. The warm up the pot with the dial at 5. I cast and drop without sorting between drops. I keep going until the boolits look frosty, then back the dial down to 4 and slow the rate of casting to a comfortable pace.

Occasionally I see a very small thin fin at the nose of one boolit but I can tell that this was from having a finger on the sprue handle and the blocks weren't tight. Maybe 1 out of 30 (or less) have this issue and its attributed to operator error.

The problem I'm having is at the base. A small amount of lead is attached to the boolit. When I open the sprue, I can see where its happening. And it happens too often to cast efficiently. Its between the block and sprue for sure.

The alloy is a mix of wheel weights and linotype. BHN is above 20.

I've checked for smeared lead on the underside of the sprue plate and the topside of the mold blocks and there isn't any.

I'll use the methods you suggested to inspect again and I'll brings some photos to the party to help better describe my issue.

[fecmech]

Make sure that the bolt for the spru plate pivot is tight and the bolt for the the other end of the spru plate where it slides under is tight also. If both are tight close the spru plate and look for light between the spru plate and top of the mold. If there is a gap there you will get the flashing you are describing. You could possibly have a warped plate or a mold surface that is not square. Let us know what you find.

[lesharris]

With the added info,I would look and check fit of sprue plate to mold blocks.
It is possible the bolts need tightening.
I cast using similar setup and have very few problems.
Preheating the sprue plate and blocks on an electric hotplate may help also.

[dfwbiofuels]

The sprue plate bolts are plenty tight.

They've been sanded flat on top multiple times. I keep getting flashing around a few of them sporatically. And I'm also getting lead between the moulds creating short feathers at the top.

The 9mm 124gr 6cav Lee mould is just not working out.

In contrast, I can get my 6-cav 230gr 45ACP mould to throw very nice looking boolits almost every time.

So frustrated.

[Colorado4wheel]

I could not find a fix for this issue. Mold looks perfectly fine. Not gap. Heat it up and start casting and you get fins in the middle cavities.

[AggieEE]

One thing I've noticed, and I don't know if it would apply in this case, but I've gotten base finning by having the spue bolt too tight. If that isn't it I'm as confused as everybody else. Just had a thought, are you contact pouring, sprue plate in contact with pot nozzel, or free dropping the stream. I just remembered that I had a problem in the past like that. Too much pressure from the lead column? AggieEE

[theperfessor]

Is the sprue plate warped a little in the middle? Maybe youve checked it already. I had that in a Lee six cavity mold. It was hard to see because it touched enough around three sides to not show much light, but it still was cupped a little in the middle and I'd get a little fin on base between block and sprue plate. A light lapping on a flat plate with 600 grit sandpaper took care of things.