HP mould has terminal wrinkle issue HELP !!!

[10 Spot Terminator]

So here it is. I picked up what appeared to be a very nice Lyman #311291 HP mould ( used ) at a local gun shop for a great price . I have another just like it but is not as nice and I was going to upgrade. I get home, fire up the pot, preheat the mold on the hot plate and start casting. From start to finish over a good 50 pours I could not get a good fill in the mould with pucker marks varying from the nose to the driving bands depending on how I varied the pour,,, fast,,, slow,,, from the edge of the sprue hole to get a swirl,,, up high in a fast drip as you would get from a bottom pour,,, you name it. Next step was to clean the vent grooves and inside of the mould so clean you could eat off it and back to casting. No difference . [smilie=b: I then decided I would lap the mould and this is where it really got me. So I had the sprue cutter laid back and had a 7/16 nut laid over the top of the boolit cavity and carefully poured through the nut until I got a nice sprue bud on top of the nut and let it cool for a good minute before opening. Much to my surprise there before me was a somewhat frosty looking but absolutely perfect boolit with a steel nut attached too it :?: :?: :?: . Of note also was the nut had a smaller than normal hole in the center of say 5/32 in. vs. 1/4 in. and leads me to ask if you have seen anything like this before and what the cure may be ??? Oh, just so you know I switched to my old mould immeadiately after this and cast 100 perfect bullets with no issues at all.

10 Spot

[stocker]

Perhaps a slight bevel on the top edges of the blocks would improve venting under the sprue plate. With only the nut on top you had no venting restriction. A few careful strokes with a good square stone held at an angle might be your solution. Check the top edges of the cavities afterwards for any burr that may have caused.

[lavenatti]

I'm with stocker, a slight bevel has helped me fix this very problem a few times.

[Larry Gibson]

Assuming you have really cleaned the mould blocks weel(?) you don't mention the alloy but a good soft malleable alloy is what you want. I suggest COWWs + 2% tin and then add 50% lead. Or, a 16-1 lead - tin alloy if you're not driving them too fast. The tin in both not only will give better fill out but will make a better alloy also. Have the alloy at 725 - 750 degrees. If the HP stem is the original it is too long and really cools the alloy down as soo as the alloy hits it. The pin must be kept hot. Photo shows what i do with a propane torch and some bent wire for a hanger. Adjust the propane flame to keep the pin just hot enough, it doesn't need to turn color let alone get red hot. With that done just get the alloy into the mould as quick as possible and leave a large sprue.

Larry Gibson

[GP100man]

I used beagling tape to offer more venting to this mold ,it had no vents .

http://i746.photobucket.com/albums/xx110/GP100man/102_0504.jpg

[Dan Cash]

Vent your ladle or the holle in the sprue plate. Increase the hole in your ladle spout to 3/16 or so.

[runfiverun]

try swapping the sprue plate from your old one over....

[10 Spot Terminator]

thanks for the input guys. I am using Lyman #2 alloy, preheated the pin and the mould , use a thermometer in my melt pot, use a Lee ladle as found it easier to control than a Lyman. I will try swapping the sprue plate as maybe there is a subtle difference. Beagleing I will try last.