Ideal 358429 issues

[mvozz]

I just found a guy selling several moulds that I just couldn't resist. One was an Ideal 358429 that I have been looking for. I started casting a few boolets right away and they were awesome! I only have one problem, I ran a few through my 358 sizer and it shows no sizing on one side of the center driving band. This tells me that this a bit out of round and needs some lapping compound applied. Am I on the right track or is the slight out of round in the center OK if the rest of the boolit sizes properly? There seems to be a lot to learn about this new hobby!

[Guesser]

My suggestion is to loob a few and size as you have and load them and try. I have a couple moulds that drop slightly out of round, but sized, loobed and loaded they seem to shoot at least as well as I can.

[Eutectic45]

Before you start cutting on the mold make sure every other possibility is OK.
Is the mold clean? Did the previous owner use one of those crappy spray on mold treatments? They can build up in the mold. Clean the mold with acetone.
Alloy at least 50F over fully melted. Mold fully heated, sprue takes at least 10 seconds to harden. Reject the first casts until the mold comes up to temperature.

"It's not the people who vote that count. It's the people who count the votes." Josef Stalin

[JonB_in_Glencoe]

mvozz,
welcome to the forum...and welcome to the madness of casting.

First, I'd say, get a 0-1" micrometer, it is the best way to measure boolits...to check size, as well as, checking for Out-of-roundness.
If the problem were the mold and you were using good technique to cast, then every boolit would have the same problem...Is that the case???
>>> If that is NOT the case, then I'd lean toward "shrinkage", if this problem occurs mostly in the center of the boolit.

Shrinkage is what happens when the sprue plate isn't hot enough, the sprue will freeze before the entire boolit freezes, The molten alloy in the mold will contract and if the sprue were not frozen, the alloy in the mold would pull alloy from the sprue into the mold, but if the sprue is frozen, the only action left, is for the boolit to shrink a bit, in the area that freezes last, typically the center portion of the boolit (like the center driving band).

[mvozz]

Just as background this is an old mould but it doesn't look like it was ever used. I scrubbed it real good, smoked it, preheated the mould and threw the first several back into the pot The boolets look great with good fill out and good crisp lube and crimp groove and a good flat bottom. I was thinking of throwing in a bit of tin to see if that helped but before i did that I thought "what the heck, shoot some and see how they work". I PC'd about 100 to see what happens. The shrinkage part has me wondering though. My lead came from a guy that was getting out of casting, it is 4/1 WW - Lino. The BHN is about 10 but I was wondering if a little tin would help here since the antimony is probably a little on the high side. Thanks for all of your input on this.

[dogrunner]

I just found a guy selling several moulds that I just couldn't resist. One was an Ideal 358429 that I have been looking for. I started casting a few boolets right away and they were awesome! I only have one problem, I ran a few through my 358 sizer and it shows no sizing on one side of the center driving band. This tells me that this a bit out of round and needs some lapping compound applied. Am I on the right track or is the slight out of round in the center OK if the rest of the boolit sizes properly? There seems to be a lot to learn about this new hobby!

I had one that was substantially out of round.........used the thing for way over twenty years...shot well, but the constant leakage of lube while sizing finally prompted me to test Lyman's warranty...........Believe it or not they sent me a brand new mould that was perfect. That was several years past, and I can tell utterly no difference in the performance of the new vs old..............might be me, but old targets I've kept suggest otherwise.


And by the way, when I say my mould was OOR.........it's condition was dramatically noticable when a bullet was viewed on either end........one block side was visually smaller.

[Larry Gibson]

"smoked it"

More than likely the problem. Suggest you clean it and leave it clean and unsmoked. Cast some and see what they measure. Also the alloy it self and the casting temp may cause that problem. What alloy?

[mvozz]

The alloy is some I picked up from another caster that was selling his "stuff". This alloy is 4 to 1 WW and lino. The BHN is 10-11.

[mvozz]

Dr. Larry strikes again! Perfect diagnosis. Cleaned the mould - preheated it and started casting great boolits. I let them cool and sized a few - Perfection. Thanks Larry!