Home Made Mold with Spiral Lube Groove

[Andy_P]

I posted a variation of this over on the "British Miltaria" Forum and thought you might find it interesting.

Here's another option for the cheapskate and/or guy who likes a challenge. With this process you can make a wide variety of molds with nothing more than drills and taps, using old (and cheap) Lee molds, and a bolt you can buy from the hardware store. Here's what I did:

1. Make the Mold - Drill out an old Lee Mold (I used a 9mm double mold) with a 37/64" drill. This happens to be my Cadet Carbine's bore size (0.578"), so the untapped part will "ride the bore". Tap the mold to your desired depth with a 5/8" NC bottoming tap. This will create sharply pointed grooves to a 0.625" depth in the mold;



3. Make a Sizer - drill a 1 1/4 NF bolt in stages to 15mm, then cut it off to about 1 1/2". 15mm = 0.5906. Which is about 0.003" greater than my groove size (perfect for cast bullets).



4. Cast Some Bullets - get the Alloy and Mold HOT! The narrow pointy grooves are tougher than usual to fill. cast a few, and after cooling apply the Lee Alox.



5. Size the Bullets - same process as for the Lee sizers. Borrow a large sizing "pin" from another sizer kit, and run them through.



6. Load and Shoot

My mold produces bullets as shown that weigh a sized and lubed ~480gr when cast from wheelweights, and are ~0.725" long, so stabilize nicely in the slow twist of my Cadet Carbine. Yes - I could just buy a 0.590" mold and save the effort, and yes, the bolt, old mold, tap and drills cost something (and the drills are a bit difficult to find), but I made my own custom mold and can apply the process to other bore sizes that match available taps such as the 5/16" (0.312"). The spiral, continous lube grooves are an oddity, but holds the lube well and the accuracy seems unchanged (this is not a MOA gun).

[StarMetal]

Interesting idea. I'd like to see how one of a more common bore size like say for a 30 cal would do accuracy wise compared to a standard cast bullet. Certainly easy enough to make. I assume you squeeze the spiral groove in the mould with the thread die inbetween the mould halves...is that correct?

Joe

[Andy_P]

Yes, I just ran the tap into the hole created with the mold closed and clamped together in a vise.

Easy enough to do for 30 cal. Take a 7mm mold and run a 5/16" -18 NC tap (0.3125") into it. For 31 cal, take a 7mm (or perhaps 30 cal) mold and run the same 5/16" or a 8 x 1.25mm tap (0.315") into it.

P.S. They have to be "bottoming taps", or the threads will not go to the bottom, at least in the larger diameter molds (0.375" +)

[9.3X62AL]

Now, THAT is something.

[Bass Ackward]

Wow Andy. Impressive.

Would make for many interesting experiemnts. Nicely illustrated too.

[crazy mark]

Do you use RH taps for RH barrels or LH taps. That would be an interesting project. Also have you tried NC VS NF threads. I think you have a neat idea and may just try it on an old junky Lee mould I have around somewhere. Mark

[Buckshot]

..................Very cool Andy! Neat Idea.

................Buckshot

[David R]

A+ for originality.

Thinking outside the box.

David

[Ed Barrett]

I can imagine someone looking at a fired bullet in the backstop and thinking, Gee that rifle has a faster twist that a 6.5 Swede!!!

[Junior1942]

Andy, you are a genius.

[KCSO]

I've been looking for a 32 cal mold for a plinking bullet for my Lebel and YOU have supplied the answer. Thanks, super idea, I will be making one tonight.

[carpetman]

If you wanted a jacketed bullet,could you just use the a piece of the bolt?

[Andy_P]

Glad to hear that my post was appreciated, but sheesh, a girl could get a big head!

A couple of things have come up on reflection:

- I made an elementary mistake when I said that a 8mm tap would make a 0.323" mold. In fact it would make a 0.315" mold which is the standard 8mm bore, not groove size
- I did up another Snider mold (0.590") from a Lee 0.575", mold and found it much easier, and of better (more concentric) quality than the one I did up from a 9mm mold. The nose shape was as original and was a better profile.

Here is a list of standard taps. The diameters listed reflect the outside diameter of the bullet that will drop. The points will be thin and sharp, so sizing down at least 0.010" would be advisable. The depth of the grooves on the tap vary, but are from about 0.050" - 0.080" for the sizes that would be commonly used for bullets (0.280 - 0.460), so you could choose a tap and selectively size down from 0.010-0.050" and be ok.

Here's a list of commonly available taps. In most cases you need a bottoming tap, but for the smaller sizes you might get away with a standard. I have added some quick thoughts on where they could be applied. Not all taps might be the same. Further, although tough, you could conceivably turn a standard tap down a bit on a lathe for custom fit and/or for less sizing to do.

Imperial

1/4-28 (0.250) - good for 22 cal and 6mm
5/16-18 (0.3125) - good for 31 cal and down
5/16-24 (0.3125)
3/8-16 (0.375) - good for 0.338 to 9mm
3/8-24 (0.375)
7/16-14 (0.4375) - good for 10mm, 44 cal
7/16-20 (0.4375)
1/2-13 (0.500) - good for 11mm, 45 cal
1/2-20 (0.500)
9/16-12 (0.5625)
9/16-18 (0.5625)
5/8-11 (0.625)

Metric

6 x 1 (0.236) - good for 22 cal
7 x 1 (0.276) - good for 6mm - 270
8 x 1.25 (0.315) - good for 31 cal and down
9 x 1.25 (0.354) - 8mm-9mm
10 x 1.5 (0.394)
11 x 1.5 (0.433) - 10mm - 44 cal
12 x 1.75 (0.472) - 45 cal
14 x 2 (0.551)
16 x 2 (0.630)

[KevMT]

I remember reading somwhere about cast boolits that were "patched" with a sprirally wound piece of copper wire. Your boolits look costom made for just such a treatment.

Kev

[Quantrill]

"I remember reading somwhere about cast boolits that were "patched" with a sprirally wound piece of copper wire."

Phil Sharpe's book, "Complete Guide to Handloading", mentions this. I would love to see a .30, .38, or .45 with this spiral lubing and hear about it's performance. Quantrill

[357maximum]

Too bad that ain't a MOA gun. Then you could literally "THREAD" them through the same hole.


EDIT: You have given me an idea for a .410 hollow base slug, thank you
It would have to be a nose pour though. Been wonderin what I was gonna do with that old 350 RB mold. Looks Foster(ish) to me.

thank you

thank you

thank you

[NavyVet1959]

The links to your photos aren't valid anymore. Could you edit your post and put valid links there?

[Andy_P]

The links to your photos aren't valid anymore.  Could you edit your post and put valid links there?

My old ISP went bankrupt a few years ago and I haven't bothered to go back through history and restore links. Thanks for the heads-up.

Here's all I can find right now:

Attachment 149279

[Fishman]

That is neat. I have to think that would work well for muzzleloaders, kind of a homemade REAL bullet.

[NavyVet1959]

My old ISP went bankrupt a few years ago and I haven't bothered to go back through history and restore links. Thanks for the heads-up.

Here's all I can find right now:

Attachment 149279

That attachment is not valid either, but it is visible in the original post that you edited... Thanks...