Fin on end of hollow point

[songdog53]

I cast first batch of HP with Lyman 429640. I had fin on one side of bullet at end of HP. It isn't always the same side. My guess is pin is either under sized or out of round. Any ideas? Other than one i came up with in my old brain. Giving Lyman call in the morning and see what they say but want your input and if you ever had this problem.

[Ohio Rusty]

I have a Lee mould that does that also. At the end of the hollowpoint hole, there is a little left over flashing. I can't say for sure what causes that. I usually don't worry about it and sometimes I trim it if the fin is a little big. I inspect every boolit I cast anyway, so I can trim or cull back to the re-melt pile as I go.
Ohio Rusty ><>

[fredj338]

Yeah or slightly the wrong shape to fit properly in the hole. You could always make another one, buy some ss or brass stock close to the size & polish down, pin it into a wooden knob & you are in business.

[gray wolf]

After casting many,many, HP bullets I would like to give my take on it.
I also get a fin on some of my HP but not all the time--why?
Well after watching what was going on this is what I have noticed.
OK - the casting session starts and all is going fine, no fin on the HP.
If I let the mold or metal get to hot I get some fins on a few bullets. As soon as the temps get right again they go away. Yesterday I was casting very fast and a little tiny bit of lead got on the pin and created a very, very small build up around the pin. I got fins until I got rid of it and then all was fine. If I hold my mold up to the light I can see a small amount of light around the shaft of the pin. This does not seem to matter at all. The biggest thing for me to watch is that the metal does not get to hot or my mold does not get over heated.
If a hp mold will make good bullet and then all of a sudden start making fins Then I don't blame the mold, but I look at my method of casting and wonder why it stars and stops.
In my case I found the answer.

[VenomBallistics]

I suspect an unequal expansion sort of thing.
the blocks swell and the cavity enlarges a hair while the HP pin tends to lengthen more than swell with the hole it belongs to.
Its honestly no big deal, and these boolits still perform very well.
if the tag is slight the nose punch will flatten it, if a bit more pronounced .. trim the tags. Its not a real problem till its rather severe

[songdog53]

I noticed that with the ones i did cast once went thru sizer luber they were either pushed back inside the hollow point or went somewhere. I didn't think it was major deal but figured i would call lyman and ask them why. I have one for 45 and it works great and no fins, just figured was pin problem.

[songdog53]

Talked to Lyman and they want mold back and some samples of boolits....got plenty to send them, I know isn't big deal but what you pay for mold these days they should be right. Reckon i'm getting too old and cranky.