ULTRA-DENSE Tungsten shot: properties and suitibility for realoding


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cpileri
November 21, 2012, 02:44 PM
Dear Sirs and Ma’ams,
Can anyone help me fill in the blanks in data in my chart, below? Any metallurgists or engineers out there?
I found a source of very dense tungsten shot (http://www.tungsten-spheres.com/tungsten_shot.html ) at ~17.5g/cu.cm and began a search for the properties of this shot as compared to lead and other shot materials. The data on the tungsten is from an email to the company, other data scoured from web searches.

Tungsten Ball AMS-T-21014: Class 2 (W 93%;Ni 4%; Fe 3%)
Density (g/cc) ~17.5
Tensile strength (Mpa) ~955
Yield strength (Mpa) ~880
Elongation (%) ~21.5
Hardness (HRC) ~29 (~290 on Vickers Diamond Pyramid Hardness scale)
Impact toughness (J/cm2) ~115

Lead Shot
Density (g/cc) 11
Tensile strength (Mpa)
Yield strength (Mpa)
Elongation (%)
Hardness (HRC)
Impact toughness (J/cm2)

Hevi-Shot (Tungsten Fe-Tin-Nickel alloys, Environ Metal, etc)
Density (g/cc) 12-13
Tensile strength (Mpa)
Yield strength (Mpa)
Elongation (%)
Hardness (HRC) (67 on HRB)-21 on HRC (120-235 on Vickers-Diamond Pyramid hardness scale)
Impact toughness (J/cm2)

Bismuth (also, sintered tungsten polymer, Kent, etc)
Density (g/cc) 9.4-10.4
Tensile strength (Mpa)
Yield strength (Mpa)
Elongation (%)
Hardness (HRC) “way soft” (35 on DPH)
Impact toughness (J/cm2)

Steel shot (soft cold-rolled- Fe alloys)
Density (g/cc) 7.9
Tensile strength (Mpa)
Yield strength (Mpa)
Elongation (%)
Hardness (HRC) (~2-2.5x hardness of lead) (90-120 on Diamond Pyramid Hardness)
Impact toughness (J/cm2)

I am going to try to work up loads for these tungsten balls for shotguns. They make .315 spheres that fit neatly into most 410 wads, in particular the Ballistics Products TPS wads. Ideally, I would like to maximize penetration at low velocities to make a useful multi-ball load for the current, faddish 410 revolvers; which suffer from in-bore pellet deformation reducing penetration and pattern. So the resistance to compression is of interest, but also their ability to not pulverize on impact.

This is the beginning of a fun project. SO thanks so much for your expertise.

C-

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JLDickmon
November 21, 2012, 11:01 PM
tungsten is a little pricier that ferrous steel, but hey, if you have a good source for it for a fair price, have at it.

I mean heck, lead is closing in on $40./bag anyway..

cpileri
November 22, 2012, 10:38 AM
So here's more of what's in my head (scary, i know) :)

I have also considered using nickle-plated lead buckshot, as well as steel balls (ball bearings), for the "deep penetrating, multi-ball, 410 buckshot" load.
I thought steel balls might be damaging to the bore (and of course, so might these hard tungsten balls). So for decreased density, and similar bore damage, I lean towards the tungsten. Nickle plated lead is cheaper and an option, if they dont deform. Federal Premium has the best non-deforming pellets, it seems, at least by Brassfetcher testing and a few other net searches. But i am working on "one up" on these. i acknowledge that these balls are super expensive.

Not only that, but the .315 balls weigh ~85grains each, reducing the shot charge by 15% vs lead as recommended by BP load data, that makes 2-3 balls as a maximum load by weight. 2 might not be worth the trouble. but 3 might.

I also thought using buffer or even a felt wad between each ball might prevent deformation, and thus allow increased penetration.

I did find a reference for use of steel, that says, "Tom Roster, working in conjunction with the Cooperative Nontoxic Shot Education Program (CONSEP) has put together a database on the performance of lead shot vs. steel shot. In this study is an X-ray analysis of over 16,000 ducks and geese...A steel pellet, with an energy level equivalent to that of a lead pellet, provides 5% to 10% deeper penetration" (bold mine)

so the lesser density is compensated for by increasing velocity such that the lighter, and non-deforming, steel pellet has equivalent energy to a same-sized lead pellet; and allows greater penetration.

My thoughts on creating this short-range (point-blank) to a few yards, "car gun style", with a very dense pellet are to allow it to penetrate with less velocity- since these 410 revolvers generate much less velocity than long barrels.

Its expensive, sure, but since its available; it struck me as interesting and as possibly contributing knowledge to the field.

C-


p.s. the 410 revolvers of the world only appeal to me for killing snakes with shot, which they do effectively apparently; and the capability of multiple hits on goblins/zombies. The 410 slug pales in comparison to the 45 Colt loads, which penetrate way more than any ball. But then it is only a single projectile. So the area of research i find a gap in is the "best" multi-ball load for 410 pistols. Given that paradigm, there is my project.

p.p.s. my other concers, besides developing a safe-to-fire load; is that when all is ready for ballistic testing this specific product, which is made by "fusing' tungsten powder, might have a maximum velocity at which they simply return to powder. That max velocity might be too low to provide any useful penetration. We'll see, i guess.

Happy Thanksgiving!

suemarkp
November 22, 2012, 03:23 PM
Keep working.... I've had similar thoughts but never done anything -- not enough time.

I do wonder about one assumption though -- in the quote "A steel pellet, with an energy level equivalent to that of a lead pellet, provides 5% to 10% deeper penetration", I'm wondering how they are getting equal energy. Are they comparing a larger steel ball to a smaller lead ball (so weights are equal), or equal sized balls with the steel one just going faster?

I'd expect penetration to correlate to momentum and not energy, so weight, diameter, and pellet hardness would be the most important factors. Velocity matters too, but since balls shed that so fast you have to ponder how that will affect effectiveness at the range you want to use it. To me, that's a plus as in an urban environment as I want any errant or over-penetrating pellets to drop like a rock.

cpileri
November 22, 2012, 03:46 PM
I beleive its same sized balls at higher velocity so that energy is equivalent. i wish i had a copy of the original work.
C-

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