Latest 25-303 PPCBoo

[303Guy]

Just made a new nose punch for my adjustable 25 mold and using my latest alloy mix, this is what I get.

118gr PPCBoo core.

Firstly, the alloy casts terribly!
On the up-side, the boolit has a very convenient nose ogive/shank junction ring. Quite by accident, this turns out to be convenient for aligning then patch! (So far, I have only patched it dry, then wet by dipping. A grerat way to apply the patch on such a tiny boolit!)

The first test firing.



Those are the recovered patch bits inside the circle.

[6.5 mike]

303 Guy, it almost looks like you planned it that way lol. What are you using for patch material ? I've been working with a 45-70 in a sharps, sooooo much easier to work with the fat boolits.

[robroy]

303, any accuracy results with those boos yet?

[303Guy]

... it almost looks like you planned it that way lol

It does! If'n I were smarter I would have made that claim. But no, it was purely by accident. But it's a trick I plan on using again!

robroy

I'm working 10-6 at the moment so no, I haven't tested them. I only did the mold nose thingy yesterday with an identical ejector punch and tried it out and found the alloy behaving in a nasty fashion. The same alloy also misbehaves in my 303 mold which used to produce rather natty boolits, in retrospect. They had a softer nose than base shank with a visible transition and the expansion stopped at that transition. (I should just find the pics and post them again - I don't have broadband so it's a bit slow to do a search).

[303Guy]

Here are the 303 Brit castings.





These are not from the same mold but the expansion point did coincide with the mold.

I was hoping to get the same result with the 25 mold but the alloy isn't responding and I can't say I got the mold right or not.

[robroy]

thanks forn the pics. carry on

[Zeek]

Dear 303Guy:
I'd like to hear how you are getting that soft nose on your core CBoo. Damn good work, lad! (As a certified Geezer, I can talk that way without conveying a fence, as it were!)

If you alloy has some antimony and a touch of arsenic (e.g., it has some wheelweight alloy in it), you can drop them CBoos into water from the mould. Or, better yet, soak them at 455F in your oven for 1-2 hours and then drop quickly into a bucket of cold water. (I know that you know this, but I include it for the Newbies among us.)

Now, here's the trick I promised. For your hunting boolits only, stand them up in a pan of water ~~~> the water is deep enough to cover the part the you want to remain hard. Dab just a touch of Tempilaq 450F/232C temperature-indicating paint on their tips [available from Brownells ~~~> it is VERY quick-drying, too]. Play a propane torch back-and-forth right at the water line of your chosen CBoo. The instant the Tempilaq at its tip melts, move on to the next one. This is quick, and gives you a hard-ass/dead-soft-nose CBoo that will shoot to the same POI as your all-hard ones from the same casting/hardening batch. So, you can develop your load, and then make up your small number of hunting PPCBoos as needed. Works, too, for GC/lubed CBoos . . . . in fact, so long as your water line is at least 1/8" up from your top lube groove, you can even do it on finished (lubed & GC'd) CBoos. Of course, that option is not viable for a PPCBoo, but that's just an RTB*

It's a way-hot CBoo trickipooh!
Zeek

* = "Reeeally Toooo Baaaaad!", as in, "Now THERE's an RTB!"

[303Guy]

Thanks Zeek. That's neat! Way better than trying to get the right alloy and right mold design and being forced to nose pour.

The trick to casting a softer nosed boolit is a mold that cools vvery quickly at the base and slowly at the nose. I developed the mold this way to achieve a good cast by ensuring freeze-shrinkage make up from the sprue with nose pour.

Here is one of the molds.


With casting funnel for hollow points.


Gas check base plug.


Lube filled hollow point.

[Zeek]

Wow, 303Guy! That is seriously cool. Is the idea that the base gets frozen fast enough to make it act like it were quenched, whereas the nose is not cooled, so goes down through its critical point temperature slowly enough to come out annealed?

Pretty damn neat approach no matter! I'm becoming a real fin of your designs.
Zeek

[303Guy]

Thanks!

Is the idea that the base gets frozen fast enough to make it act like it were quenched, whereas the nose is not cooled, so goes down through its critical point temperature slowly enough to come out annealed?

Yup. Who'd have thought it possible? I discovered this purely by accident of course (wish I could say I planned it that way! )

The fins on the mold were supposed to increase heat transfer area while keeping the mass high. The idea was also to be able to heat the mold up quicker. (I also thought it would look cool!)