A boolit under 370 grains for the 43 Spanish?

[ohland]

A whole buncha issues to sort out.

Chamber that likes .439 boolits and a .445 groove. Because of this, the boolit must bump up when fired. BUT... without as much weight, will this impede the black powder combustion?

The dimly sought after goal is a 250-300 grain boolit that would bump up upon firing.

HB?

[Mk42gunner]

I don't know if it will work, but I have thought about paper patching ~.430" boolits up to work in the .43 Spanish. I never got around to trying it though.

Also I believe RCBS makes, or did make a 340 grain FP .439" mold. Finding one may be a problem.

Robert

[ohland]

I don't know if it will work, but I have thought about paper patching ~.430" boolits up to work in the .43 Spanish. I never got around to trying it though.

Also I believe RCBS makes, or did make a 340 grain FP .439" mold. Finding one may be a problem.

Robert

PP might not work with the tight chamber / big bore.

[Mk42gunner]

Like I said, I never tried it. My bore slugged right at .440" IIRC, so I wasn't too worried about making the boolit obturate upon firing.

One of these years I will have to get back to that project....

Robert

[fouronesix]

A whole buncha issues to sort out.

Chamber that likes .439 boolits and a .445 groove. Because of this, the boolit must bump up when fired. BUT... without as much weight, will this impede the black powder combustion?

The dimly sought after goal is a 250-300 grain boolit that would bump up upon firing.

HB?

Efficient burning or impedance of the BP burn would have little to do with it. The less massive the bullet… the less inertia thus less obturation. The more massive the bullet... the more inertia thus the more obturation. And with all other things being equal… the softer the alloy the more obturation.

[montana_charlie]

http://castboolits.gunloads.com/attachment.php?attachmentid=144270&d=1436623362&thumb=1

How far below the bottleneck is the base of your bullet?




A whole buncha issues to sort out.

Chamber that likes .439 boolits and a .445 groove. Because of this, the boolit must bump up when fired. BUT... without as much weight, will this impede the black powder combustion?
Poor combustion with so little bullet weight?
Crimp bullet, or try less powder.

Insufficient bump up?
Use softer alloy.


PP might not work with the tight chamber / big bore.
What is the bore diameter of that barrel?

CM

[ohland]

How far below the bottleneck is the base of your bullet?
Poor combustion with so little bullet weight? Crimp bullet, or try less powder.
Insufficient bump up? Use softer alloy.
What is the bore diameter of that barrel?
CM


Arrgh, you would have to ask... Staggered downstairs and found a few sized but unloaded boolits. They measure .440 in diameter, .977 in length.

Case is about 2.258, complete cartridge is 2.786 long. Means the boolit sticks out .528, more mathochism, .977 minus .528 is .449, which means this puppy is jist above the base of the neck. Case neck length is .495. So... add .060 to .449 and we have wa-la, .509. Which suggests to me the card sticks down below the neck about .015

So how significant is that? If you notice the boolit has got some wiping action on the drive bands.

144295

The current duplex load (5gr 5744 / 70gr FFg) under a 370 grain boolit burned clean (which may be a wee bit excessive with the 5744). If someone does come up with a lighter bullet, maybe the OR will figure out that crimping is what needs to happen.

When I do snag a 43 caliber mold, then I will cast a softer alloy. I have a Pro-Melt with @ 10-12 BHN alloy that I'm futzing about with. These will be air-dropped, because water drop added about 6 BHN to the alloy... Present mystery boolits are not leading.

I need to melt down the RCBS 44-370-FN I cast up (Yes, I understand they cast @ .445)... They were WW, water drop, about 19 BHN, would not gracefully size down to .439, really made my LAM II sweat...

Bore / Groove is .439 / .445

[montana_charlie]

Which suggests to me the card sticks down below the neck about .015

Bore / Groove is .439 / .445
Others can tell you if it's a 'bad idea' to have a card wad 'floating' below the bottom of a bottleneck.
I think you would be better off without it.

If your bore is .439", and your chamber will only accept a bullet no larger than that diameter, it sounds like a natural-born situation for bullets patched-to-bore ... and set out far enough so the bullet base is still inside the neck.

With an onionskin paper that will increase diameter by (say) six thousandths, a .433" smooth-sided bullet should be a good candidate.

No need to resize cases once they have been fireformed in that chamber.
Just clean 'em, put in a primer and powder, and thumb seat the bullet.

Find the paper and do some measurements before settling on a bullet diameter ...

CM

[ohland]

Others can tell you if it's a 'bad idea' to have a card wad 'floating' below the bottom of a bottleneck. I think you would be better off without it. CM

Well, I have a 439186 inbound, ditto for a Forster original case trimmer, a #4 collet for it, already have a #251 top punch.

Working up enough enthusiasm to attempt another chamber cast, which I will tap out NO LATER than 5 minutes after pouring...