Boolits mould design testing

[snowman]

I have been toying with the idea of making boolit moulds for quite a few years....in a production/custom manor. I have made similar molds before, but not to sell.

Is anyone able to suggest a specific mould that could be made....a well known boolit....for beta testing by some cast boolit members that could give some public feedback?

I just want to make sure that my work is up to par, before I buy vendor membership or offer to take on a custom group job.

[Sweetpea]

H&G 68, Lyman 311299

[runfiverun]

umm I think sweetpea meant the 311299.

anyway if you really want to test your ability at mold making, a 22 mold is about as difficult as it gets.
getting 4 cavity's in under a .5 gr weight range and consistency from cavity to cavity will test your skill.
that or something with square lube grooves and drive bands.
if you can make them drop easily and maintain their square shape you are in the good.

[Sweetpea]

umm I think sweetpea meant the 311299.

anyway if you really want to test your ability at mold making, a 22 mold is about as difficult as it gets.
getting 4 cavity's in under a .5 gr weight range and consistency from cavity to cavity will test your skill.
that or something with square lube grooves and drive bands.
if you can make them drop easily and maintain their square shape you are in the good.

Yep, the brain and fingers had an interface issue...:veryconfu

Run has a good point on trying out the hard stuff... work on a loverin design.

Brandon

[StratsMan]

umm I think sweetpea meant the 311299.


Yep, the brain and fingers had an interface issue...:veryconfu

I guess I don't get why Sweetpea was confused...

But I'll throw in my recommendation to test your skills against the H&G 68... Every decent mold maker has their own copy/variation of this design, and with good reason... I'd throw in the H&G 34 to compare against the 452374, as well... and if you're in the mood to try hollowpoint molds, the MP 200 is already a HP variant of the H&G 34, and is a well thought of mold on this forum... I'm sure many would be happy to critique any of those designs, as many here are currently casting with the originals...

[turbo1889]

The for-mentioned 311299 design is an a very popular design that requires the mold cutter to get too critical diameters correct and not out of round. This is because it is a bore-rider design and on such a design the diameter of the bore rider section is the most critical dimension, even more critical then the main driving bands diameter. Its okay to go a little fat on the body and fudge the tolerances to the high side to cover and the customer can easily just size them down to fit his/her gun. The bore rider diameter must be correct, however, because you can't just size it down in a sizer die. For that design the bore rider is suppost to be at minimum 0.2990" diameter and at maximum 0.3010" diameter regardless of which harder alloy the boolit is cast from in order to ensure decent results in most guns. Because alloy differences on the hard alloy end of the spectrum (from about straight WW up to straight lino-type) can make up half of that tolerance range alone for a bore rider boolit design with a long bore rider nose you have to hold really nice and tight tolerances produce a high end quality mold that will consistently produce boolits that have the correct bore rider diameter within a narrow tolerance range from the mold without any post sizing.

If your just starting out as a group buy mold maker I suggest that you do not do a bore-rider boolit design for your first run or two. The tolerances on the bore rider section of such a boolit are the tightest set of critical tolerances your going to run into. On designs that do not use a bore-riding nose you can just run the tolerances on the fat side and the customer sizes down to fit their bore. You can get away with double or more the tolerance range on the body diameter provided you slant it to the fat side and it just gets sized down. Doesn't work that way with a bore-rider mold, they have to drop from the mold at the correct diameter within a very narrow range with no sizing required at least for the bore riding section.

[MT Chambers]

I can't add much except to disagree with Turbo and then it's only minor, many of us do indeed size the bore riding portion of that bullet and others, to tailor the bullet to individual barrels.

[quasi]

the competition is pretty good for Custom molds now, I would suggest looking for some nich markets. E.G. no one makes a gang mold in large round ball dia's. A .690 dia round ball gang mold might sell very well, as well as a .730

[turbo1889]

Didn't say it was impossible to size the bore-rider. Just not normally done, at least that I have seen. Maybe a few who do it. Me personally if I have to size the bore-rider portion and my bore is normal size I consider that to be a faulty mold that is not within spec. If my bore isn't normal dimensions then that is a different story.

[turbo1889]

the competition is pretty good for Custom molds now, I would suggest looking for some nich markets. E.G. no one makes a gang mold in large round ball dia's. A .690 dia round ball gang mold might sell very well, as well as a .730

Oh, yes, yes, yes !!!

Round ball gang molds in a set-up like a Lee six-cavity block in custom sizes with a small Tangential-Cut sprue plate nice and round in whatever size we want from about 0.300" up to 0.800" would be a beautiful addition to the custom mold makers available with progressively less cavities as diameter increases down to just three cavities for the really big balls.

As a side note along those lines, I have long felt that the way to make such molds across a wide range of sizes as on-demand customer selected sizes would be to make the blank blocks up in mass and have them in back-stock ready to go and use a jig under a CNC milling machine with a program written into it where you just typed in the desired diameter as a three digit number and using a spiral cutting pattern the milling machine would cut half cavities in the inside mating face of one side of the block one side at a time using a smaller standard size ball end mill head cutter and you just run the program twice once for each side. Granted you would have to have a good precise jig and precision cut blocks to fit that jig to ensure clean exact mating of the two block halves to produce a nice clean ball but similar had been done before. MiHec cuts his boolit molds using a CNC mill with an undersized cherry one block half at a time and he gets a clean on center mate up between the two block halves and his molds are beautiful.