Bullet deformation on mold release - help needed

[bslim]

I'm running a Master Caster with a 105 grn. - 360 dia. mold. On this particular mold, when the casting is released from the mold, I get an indent in the bullet that runs from the base up along the bearing surface. Thinking my cycle time was too fast and the bullet was coming out too hot, I slowed my cadence down to the point that the lead had a long time to solidify. This didn't solve the problem, so I changed my formulation to increase hardness. This also did not help. I dropped my casting temp by 75 degrees, no luck. My problem is that, I cast a lot of different bullets with various molds and I only have this problem with this 105 grn. mold.
Thinking that I might have a mold problem, I ordered a new mold from Tom @ Accurate Molds and ended up having the same problem. This crease/ drag line/ indentation in the bullet is so severe that when I lube the bullet, the lube travels up the casting from the lube groove, into the crimp groove and many times to the upper part of the bullet.
It looks to me that when the mold is opened and the casting is spun/jarred out of the mold, the bullet gets creased / indented at the mold joint? Any help would be appreciated, Thx.

[bedbugbilly]

Any chance you could post a couple of photos of the cast bonnet with the defect? Thanks.

[Artful]

Do you have a video camera that you can set up to film the release to confirm your theory?

[bslim]

I tried to get a good photo but my camera does not show the defect clearly. I will try to borrow another camera and see if I can get good results. The indentation is not on the mold joint line but right beside it.

[popper]

Is the sprue plate working/vented correctly? I've had the same problem on a 30 cal, sprue venting wasn't right and get a 'crease' from nose to base. Broke the top edge of the blocks and problem solved.

[260 Striker]

I had a mould that was very difficult to get the bullets to fall out. By the time I had pounded on the pivot bolt and the bullets released each bullet had a small indentation parallel to the parting line. I think the last jarring that released the bullet actually caused the bullet to bump into the edge of the mould block as the bullet fell out. Mine were not deep so I wasn't getting the lube problem as you describe but it sounds like the bullets are hitting the edge of the block as they fall out. On a double cavity block one bullet would stick in the right half and the other in the left half. When they both stuck in the same half the scratch was not as bad when they finally released. Once the blocks open I make sure to keep them wide open so the bullets would not hit anything when they finally release. Some blocks just don't like to give up their bullets. I think designs with more lube grooves and ones with square bottom lube grooves tend to be finicky like that. At least in my experience.

[44man]

Check the inside edges of the cavity for a burr. A little piece of Scotch Brite will polish there or even an ink eraser.
Most times you can't even feel a burr with a finger nail.

[bslim]

The indentation is vertical from the base of the bullet to the top of the bearing surface. Because the indentation is not on the mold parting line, but right beside it, I'm thinking this is not a a casting defect but is actual contact with the mold upon release. With he fact that I'm using a Master Caster, releasing the bullet from the mold is restricted to the actual function of the machine. I changed the mold to my 130 grn / 38 cal. and I can see a very slight defect mark similar to the 105 mold, but, not as deep and as such does not cause me any lube problems. Might just be a complete mold design issue?

[44man]

The indentation is vertical from the base of the bullet to the top of the bearing surface. Because the indentation is not on the mold parting line, but right beside it, I'm thinking this is not a a casting defect but is actual contact with the mold upon release. With he fact that I'm using a Master Caster, releasing the bullet from the mold is restricted to the actual function of the machine. I changed the mold to my 130 grn / 38 cal. and I can see a very slight defect mark similar to the 105 mold, but, not as deep and as such does not cause me any lube problems. Might just be a complete mold design issue?

True, the boolit is dragging on a burr, worse if the boolit is still soft. Can you change sprue cutting and drop times with your machine

[44man]

One other thing to look for. Cut soft and a boolit can spin in the mold. Once lead is set, bumping the mold will not hurt the boolit.
I bet the bad spot is to the right of the parting line. Your boolit is moving in the mold.

[runfiverun]

it's from the mold being opened by the machine.

look at the bottom V-block where it pushes the arms apart you probably have a mis-alignment.
or you have the top rails off-set from the V-block and it's shifting everything over when you open the mold.
you want the rails square to both the V-block and the sides of the machine, not all molds or mold body sizes take the same settings.

[fredj338]

This happens occasionally when I use the MC. I went to a folded rag in my catch box & never let more than 3-4 drops go before moving the rag to the top again. I think the bullets occasionally hit another bullet just right & I get a flat spot or even a ding in the base. Try that?? The mold could be misaligned, but it doesn't happen with every drop.

[bslim]

step 1: I took very fine steel wool, put it on a drill adapter and polished the inside of the mold. then I buffed the edges of the mold at the parting lines. I still got the indentations. Step 2 will be to align the mold to the V blocks that open it up.
fredj338: The indentation is the same every time,virtical, so I'm thinking this is not a drop problem from hitting another bullet.
I will also try to fill the mold and let it sit for 5 min, then drop it and see if this makes any difference.
Thanks "runfiverun" for the input, I hadn't thought of the mold alignment to the V blocks.

[bslim]

Found the Problem!
The side round rails that guide the mold as it travels up & down were not adjusted properly at the bottom of the stroke where the sprue is cut. I had too much play at that point and as the sprue was being cut, the mold was allowed to partially open causing the casting to spin in the mold. Once the clearance was corrected, the indentation disappeared completely.

Thanks guys for the input, got me working in the right direction.

[44man]

Found the Problem!
The side round rails that guide the mold as it travels up & down were not adjusted properly at the bottom of the stroke where the sprue is cut. I had too much play at that point and as the sprue was being cut, the mold was allowed to partially open causing the casting to spin in the mold. Once the clearance was corrected, the indentation disappeared completely.

Thanks guys for the input, got me working in the right direction.

I was correct, turning boolit.
Good for you to solve it.