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Ken Hansgen, 11094
10-17-2010, 09:14 PM
I've noticed when I run some of my bullets thru the lubrisizer, I get a little lube squeezing past the front of the bullet at one spot, where a sizing mark does not appear. Why are these moulds irregular? I have often warmed them by dipping a corner into the molten lead--has that warped them? I'm suspecting this contributes to inaccuracy.

Southron Sr.
10-18-2010, 11:21 AM
Dear Ken:

Yes, your mould could be warped. Now, I don't know IF dipping a corner of a mould in a pot of molten lead to pre-heat the mould will warp a set of blocks-but I don't recommend doing it. I have found the best way to pre-heat a mould IF you use an electric pot is to simply place the blocks on the lip of the lead pot when you turn it on. That way, the blocks heat slowly and evenly.

Another technique I have used in the past is to EVENLY heat the blocks with a propane torch, starting with the cavity. Care must be taken to NOT oveheat the blocks when using a propane torch.

Are you using a RCBS of Lyman mould? These moulds are made using the "cherry" method and sometimes they come from the factory "out of round," i.e., oval shaped. This discrepency is sometimes hard to spot with the naked eye. That is why I have such a high regard for lathe bored moulds-they come off the machine absoutely "round."

I would suggest replacing your mould. Whatever you decide, GOOD LUCK!

Ken Hansgen, 11094
10-18-2010, 12:37 PM
Brannen, I have found this problem in both a Rapine and a Lee mould. Who makes the "bored" moulds?

Pat in Virginia
10-18-2010, 04:57 PM
Ken,

It is possible the problem lies with the lubrisizer. I have an RCBS lubrisizer and when I use the set screw to tighten the top punch it takes the top punch off-center. To rectify the problem I just don't tighten the top punch set screw any more.

Try that and see if your problem is still there. It's a cheap fix. It's also worth knowing that the lubrisizer can actually introduce out-of-round bullet inconsistencies. It's easy to check for: 1) you can get out your calipers and take measurements; 2) you can give the bullet a quarter twist after sizing and send it down again. If you feel resistence similar to what you did the first time you sent the bullet down, you have the problem. Just don't tighten the top punch set screw and see what happens.


Pat in Virginia

Paul Lampman 263V
10-19-2010, 04:14 PM
I also had an issue with Rapine molds a long while back. Seems that the blocks were assembled off center from each other causing a seemingly out of round condition. Had one set replaced twice and never got a perfect mold. Decided to look elsewhere.

Paul Lampman 263V
10-19-2010, 04:15 PM
I also had an issue with Rapine molds a long while back. Seems that the blocks were assembled off center from each other causing a seemingly out of round condition. Had one set replaced twice and never got a perfect mold. Decided to look elsewhere.

Paul Lampman 263V
10-19-2010, 04:41 PM
Sorry about the double post, sometimes I loose patience with this antique. Anyway check out the bullet with a micrometer or dial caliper to check roundness out of the mold. If it's not round then it will be sized with one side lube grooves deeper than the other, allowing lube to squeeze by.

Ken Hansgen, 11094
10-19-2010, 09:24 PM
I tried Pat's suggestion on my Lyman Lubriser--that wasn't it. Tomorrow I'll mike the bullets. Thanks, KenH

DAVE FRANCE
10-19-2010, 11:22 PM
In addition to the molds being made imperfectly, the bullets will come out of the mold out of round because as the mold cools the bullet does not solidify evenly in the mold. I confirmed this with a couple N-SSA members who make molds for castings (but not bullets).

The molds can't cool evenly because the distance from the mold cavity to the outside of the mold varies. I think that as the lead solidifies the coolest part of the melt, takes metal from nearby melt that is hotter. I know this is true for very large castings. Large castings have several sprues (a columns of molten metal) that feed metal to the large casting as it solidifies.

I have two very accurate custom made molds, and they are better, but they won't give perfect bullets. It is really asking a lot to expect a bullet to come out of the mold perfectly round to within one thousandth of an inch.

It does help to get good castings by keeping the melted lead a consistent temperature. It took me 25 years in the N-SSA to realize that using two pots would help. I never put cold lead into the pot. I take lead from one pot that is used to melt the cold ingots, and put the molten lead into the pot I pour from.

David

David

Southron Sr.
10-20-2010, 07:53 AM
Dear Ken:

You would have to check with Ray Rapine, but I have a suspicion he uses cherries, but I am not sure.

As for Lee, they advertise that they lathe bore their moulds.

Your problem might be using aluminum moulds. Aluminum is a very poor choice to use to make moulds out of; but everyone makes their moulds out of aluminum because it is so cheap to buy in bar stock form compared to brass.

I only make my moulds out of BRASS. If you ever get used to using a good brass mould, you will never go back to aluminum. Brass is 1000% better!

Your Friend,
Brannen

DAVE FRANCE
10-20-2010, 10:36 AM
Southron,

I think your comments about aluminum molds are correct. Aluminum can be a strong as steel, but the strength goes down as it is heated. I used aluminum molds at time for years but I found the aluminum would warp if I got the mold too hot. Aluminum probably works better for molds that cast small bullets. Casting large bullets just puts too much heat into the mold.

David

Ken Hansgen, 11094
10-20-2010, 03:04 PM
Brennen, I didn't know you make moulds--do you sell them too? Who sells brass minie moulds? I like those that have a captive base plug. You're right--the moulds I'm using now are all made of aluminum.

Dave, The .58 bullets I miked varied up to 3 thousandths between cross-sections (90 degrees apart) for the same bullet.

mike owsiak
10-22-2010, 10:07 AM
call MIKE for brass molds 856 596 0177...........THANK YOU

DAVE FRANCE
10-26-2010, 09:25 PM
Received a new 4 cavity mold in the mail today. It is cast iron, not aluminum.

The mold mating faces (or at least one of them) is not flat. When I hold the two mating faces together, I can rock the halves and see a gap at one end. If I were to use it, I am sure it will leak a little between the halves.

Caveat emptor!

Buyer Beware!

David

John Wells 3rd US
10-27-2010, 08:15 AM
Check for flatness of the mating surfaces. Occasionally the dowel pin holes have a tiny bit of a burr that can cause incomplete closing. Put a piece of 400-600 grit "wet&dry" paper on a piece of plate glass. Light oil, work the mold half carefully in a circular motion. Look for a bright ring to appear immediately around the dowel hole. If it does, just a few more turns will solve the problem. Just fixed one of these the other day.

another cause is slight over-protrusion of the dowels themselves. Usually they are a press fit. Tap the dowel in slightly with a brass hammer and recheck for the rocking motion. If it disappears, then that's the problem. If solved, the assemble the blocks and check for shear motion. if there's any, then one of the dowels needs slight INCREASED protrusion. A light tap or two from the other direction using a closefitting punch will solve it. The difference between "just right" and too much/little is only thousandths of an inch. Fit and try works best

On the original question, NEI handtools and Brooks Molds, and Colorado Custom bullets all make lathe bored molds. Brooks gets very high reviews, but not sure if they make any minie designs. NEI makes quite a few minies, but I think quality is a bit down since taken over by the new owner. Most of their molds are cut with cherries, but I believe they're still capable of lathe boring (Walt Melander, founder, died a few years ago--good guy!!) Colorado custom makes Hoch molds, more or less copies of the old Harry Pope nose pour molds. That design isn't conducive to hollow base/point designs.

Cherried molds are often out of round +- a thousandth. Your variations in measured diameters from the same mold are due to variations in lead and mold temperature, unless you have a mold that is closing incompletely, but usually that results in finning along the parting lines of the bullet unless metal temps are really low, and then quality suffers from wrinkling and weight variation.

hp gregory, 9128
10-28-2010, 07:32 AM
i have to wonder how much differance a few thou out of round makes for offhand shooting. i have several hundred molds and i doubt that i have one that tosses a bullet thats perfect. even if you have the rare mould that does cast a perfect bullet in most cases you have to size it to fit a musket bore. more than a few thou damage can be done during this process. very small imperfections in the bullets are normaly taken care of in the barrel when they are fired. some of the moulds that i see the best results out of toss some realy ugly bullets. dont know why they shoot well but they do. i think you just have to try each mould to see what they will do in a particular gun.perfection for our game is determined by the end result. pretty is as pretty does.
hp

DAVE FRANCE
10-28-2010, 09:48 PM
Good advice.

I just cleaned up the mold well and it fit together well. I always clean molds after using them before I use them again. It saves a lot of problems. But I never had a problem with a new one before.

Thanks!