Soft Base / Hard Nose

[Good Cheer]

Looking at the way sabots work, with the plastic being expanded to the rifling by the inertia of the bullet.
Has an expanding soft alloy plain based bullet been used with an angular cavity in its front with a hardened alloy front portion up front serving to expand the softer?
Something sort of like this, give or take a little geometry where you please...

http://i791.photobucket.com/albums/yy192/SNARGLEFLERK/hard%20nose_zpscytchfm8.jpg (http://s791.photobucket.com/user/SNARGLEFLERK/media/hard%20nose_zpscytchfm8.jpg.html)

[BK7saum]

Really don't see why you would try. Interesting to think about the possibilities. Are you wanting it to separate? Otherwise, a hard or medium-hard cast alloy will expand and seal just fine. Just how hard do you want on the front half? It is easy to get hard enough to resist deformation on impact and have minimally damaged recovered boolits.

[Ballistics in Scotland]

It has been done before, and if memory serves me rightly Lyman or before them Ideal used to make moulds for them. The point had either straight or slightly reverse tapered sides, and they required swaging together, but no more, I think, than you would do in sizing a bullet. There were also British bullets for thick-skinned big game which had similarly shaped steel points.

Their main use, however was for rifle bullets with elongated points, which were liable to slump, and perhaps slump asymmetrically, in maximum acceleration. Like many another thing in firearms technology, it would be at worst harmless if very precisely executed, and perhaps better. Your drawing looks like a pistol bullet, and in that application I doubt if they would be worth the trouble and the risk of getting the mass off-center.

[Col4570]

Ned Roberts Book the Muzzle Loading Cap Lock Rifle goes into detail about two part Bullets with a soft Base and a hard Nose.

[bubba.50]

this is an interestin' thread. I always thought it was done the other way 'round, a soft nose for expansion & a hard base for weight retention/penetration.

[Good Cheer]

Ned Roberts Book the Muzzle Loading Cap Lock Rifle goes into detail about two part Bullets with a soft Base and a hard Nose.

Don't recall seeing it. But it's on a shelf about ten feet away.
Like everything else having to do with cast boolits, somebody somewhere sometime is bound to have tried it out!

[Nobade]

Lots of slug gun shooters make bullets like that. Swage the nose in one die, then use that as the nose in the next die to make the whole bullet. That way you get a hard nose that won't slump and a soft base to seal the bore and grip the rifling.

-Nobade

[RobS]

Seems to me that one would want a boolit that fit the bore so the thought of having a super soft alloy to obturate wouldn't be needed. I too would be more in favor of a hard base to hold the rps and prevent skidding while having a softer nose to ensure expansion. Then again I don't muzzle load anything.

[Ballistics in Scotland]

Ned Roberts Book the Muzzle Loading Cap Lock Rifle goes into detail about two part Bullets with a soft Base and a hard Nose.

Ah yes, the book of which my NRA leather and gold-tooled edition used to get me quickly through customs searches in Saudi Arabia. Like my WW Greener in the same edition is just the style in which they bind the Koran, and they generally thought any religion was better than none when it came to the likelihood of smuggling.

I have consulted it, and he goes into quite a bit of detail. He says the part-bullets come quite rough from the mould, and need to be lightly oiled and swaged by a process which doesn't seem very different from the swaging of a lead bullet from a cylindrical core. He illustrates bullets in which the joining tenon is on the front and fits into the rear, and vice versa. There is also much disagreement on whether the base should be flat, concave or convex, which he appears to respect without any great belief that you can tell the difference by results. The tenons and holes he illustrates are long and conical.

I have an early Lyman catalogue of unknown date which illustrates moulds for two-part bullets, only in .30 and .32 calibres - not the large ones for which I would have thought it would have worked better. For what it is worth, the .30 has a fairly long nose and a straight tenon coming only partway down the nose, but the .32 has a fairly short nose and a reverse tapered tenon coming back to the first groove, which it would surely be difficult to swage tightly and accurately in shape. They say they can be used for either soft or hard pointed bullets, but they might mean as hard as the rest of the bullet. They also mention the use of two moulds rather than two cavities in one. So there must be a lot of orphaned moulds lying around which nobody knows what to do with.

The use of these moulds to give a soft point is feasible, but getting good results on game with a one-piece bullet at black powder velocities is feasible too, and they leave less to go wrong. I think they would come apart after some penetration, but not small parts, and that is quite adequate for most game.

Roberts also quotes the mean deviation of the Whitworth hexagonal-bore rifle at 0.37 feet at 500 yards, bringing it pretty much into line (and at longer range) with the American rifles of the time which used cylindro-conical bullet and false muzzles. It gave effective accuracy against a body of troops at 2000 yards, in the brief period when field artillery couldn't. But it finished testing in 1837 the year of the Great Mutiny in India, which was a reminder that the test of a military rifle isn't how good it can be, but how easily it gets worse in heavy use.

[ironhead7544]

Lyman made some 2 part molds years ago. The front was the softer piece and was meant to expand. These worked as advertised but were very labor intensive. Lack of popularity got them discontinued.

There was also a specific weight sized ladle that would be used to make a nose. Then harder lead would be added for the base.

Some other methods were devised but never became popular.

[country gent]

A quick easy way to test this would be to make a dipper to hold the noses amount of lead. Run 2 pots 1 with your soft alloy and a smaller one with the harder alloy. Make a pour with the sized dipper of hard alloy into the mould then fill with the base alloy running fast and hot. You want to keep the nose portion molten or close to it so that when the bases metal is poured in it bonds together in a seamless joint. Fast pours on both. The sized dipper can be made from a pistol case measure the nose length in the mould to be used and angle the case mouth of the case above this point. This makes a nice pour spout forthe dipper. at the desired hieght on the low side ( opposite the pour spout) measure up the hieght needed for nose volumne and drill a 1/8"- 3/32 hole. In use this will allow lead to run out to a consistant volumne in the dipper. When done and poured correctly the only thing you should see is the slight diffrence in color of the 2 alloys. Things you need to do to make this work are slightly higher lead temps 725*-750*. A preheated mould to get started for faster results, Faster pours to get lead into mould quickly so the mass holds heat better, and a faster cadence to keep mould hot and bullets bonding better. It works and can be done takes some practice to do. Leave the dipper in the lead to hold as much heat as possible.

[Ballistics in Scotland]

Tin and antimony both have a much lower specific gravity than lead, so there would be a considerable likelihood of the bullet's mass being off-centre. If a part-bullet made in one mould could be held accurately in another, fusing of the alloys might take place.

[Fishman]

BruceB had a whole write-up on this as I recall, and it was a sticky.

Edit: Found it. It was for casting a soft nose of course, but the approach is relevant.
http://castboolits.gunloads.com/showthread.php?11749-Casting-Softnose-Bullets-From-ANY-Conventional-Moulds

[Good Cheer]

Wonder if the Lee flat nose minie design might be a candidate for this type of expanding body.
Guess it's time to dig in the toy box and find one.