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View Full Version : Still having trouble with RCBS mold



BobinIL
06-14-2009, 08:48 PM
This is the 32-170-FN mold I posted about earlier. This mold continues to drop at .325 to .326. Some bullets I can not even get the gas check to fit on the bottom. also I am having a lot of trouble getting smooth bullets. The bullets are always rough especially around the nose. I am also having truble with it frosting just in the middle. The nose and base are shinny but the middle is frosted. I have used Frankfort arsenal drop out on it, I have cleaned it several times trying to get it to drop smooth bullets. I have also tried several different alloys and temperatures. This is the most frustrating mold I have owned. I think I am going to send it back for an exchange especially due to the over size.

P.S. I have also ordered the Ranch Dog mold to try out.

anachronism
06-14-2009, 09:37 PM
The stripe down the middle is from the groove cut for mounting the handles. My RCBS moulds, & even some of my Lymans frost there first. The mould could be oversized, anything is possible, I've never had an out of spec RCBS, but there's always a first time.RCBS stated in their manual that their moulds are cut for linotype, so I'm surprised the bullets constantly too big, I'd expect it to be on the small side with wheelweights or softer alloys. I'm sure RCBS will take care of you.

sundog
06-14-2009, 09:54 PM
Not oversize as far as I'm concerned, just right. It's uncommon for someone to have a problem because a mold drops too big. Are the blocks closing properly? I've had more than one RCBS mold that need a little help in the pin alignment arena -- check it close. Can you see daylight through the part line when the sprue plate is open and holding it up to the sun? Shouldn't. Sometimes those holes get a little cratered during manufacture, no big deal. Clean them up.

As far as the frosting goes, slow down to an even steady pace. It's not necessary to produce four thousand rounds an hour.... A damp cloth waded up beside the drop towel can help keep a even mold temp with a light touch, and a 'sssss', every or every other throw. The other reason for a localized frosty spot (and sometimes void) is the mold is not clean.

The RD mold is gonna cast large also, on purpose. What size exactly are you looking for?

BillDan
06-15-2009, 01:03 PM
SunDog is right. When the cherry is cut, it's almost never oversized. When new, it cuts the largest bullets, but as it wears, the resulting bullet diameter decreases. That's why the undersize bullets are a common complaint. Make sure the mold is closing 100%. If you have to, knock out the alignment pins and lap the mating surfaces. Then, cleanliness is next to godliness. Minor frosting is immaterial. Molds are like women. You have to stroke them just right once in a while to get the best out of them.

Leadforbrains
06-15-2009, 01:06 PM
I would check the face of the molds for any small lead splash residue.