Tin and Hollow Points

[Blackwater]

Many years ago, I used to shoot a LOT of the Lee .357-150-SWCHP's. I conducted an experiment with plain WW's, WW's +3% tin, and WW's + 6% tin. Typically, if any substantial resistance was met from mid-level .357's and a 4" barrel, the HP would open up, but the nose would break off, usually in about 4 pieces, with the base carrying through and flattening out a bit on the way through. With 3% tin added, the break-offs weren't as bad, but were still there. With 6% tin added, the HP's performed almost flawlessly, opening up beautifully, and seldom breaking off unless it hit something hard on one side - in short, about as good as a bullet can perform. Nothing I shot seemed to care much which alloy I used, but I now have a 2" .38, 4" .357, and a 7.5" and 20" barreled .44's. I want to shoot that same Lee bullet in .38/.357, and the 429215 HP in the .44's, and I'll probably spring for enough tin to make my alloy 6%, just because the recovered bullets just plain look PRETTY, and that's satisfying too. Maybe it'll help get extra penetration if I run into a sasquatch or something else big, like a big ol' piney woods rooter with an attitude or something.

I re-read the Lyman handbook's section on bullet alloy, and they too found that 6% tin seemed about optimum if you want expansion and maintained bullet "integrity." This got me to thinking, and though I used to work with a metalurgist quite a while ago, and picked his brain at every chance I got, I still don't know WHY the addition of 6% tin makes such a pronounced difference in the bullets' terminal performance. So, my question is, just exactly what does that 6% tin actually do? Does it change the crystaline microstructure, or what???? I'd really anyone with knowledge on this particular subject enlightening me on the REASON for this marked and repeatable difference in lead alloys. Thanks for any input/insight you can give.

[paul h]

It makes the lead more maleable, but I don't know the physical reasoning behind the change in the physical property.

Even with the high cost of tin, you could make up a batch of 6% tin bullets for using use and practice with straight ww bullets.

[jmort]

I'm pro-tin. I believed that you want tin to max out at same percentage as antimony in the alloy. Need to check the 6% tin out for expansion and integrity.

[303Guy]

I've tested high tin plus copper (low antimony) and they held together well in both sand and compressed ground rubber.

[cbrick]

I did a bunch of testing with clip-on weights and both 2% and 3% Sn and the only real difference I noticed was the Sn going away faster, I dropped back to 2%. Testing @ 6% could be interesting, Sn does make a Pb alloy more malleable & slightly tougher, deform more while not breaking apart. If you do this again please post your results.

Rick

[Forrest r]

It really depends on the speeds of the boolit that will be the deciding factor of the tin/alloy ratio. A 20 to 1 lead/tin ratio (5%) doesn't do very well in a snub nosed revolver around 800fps or mag velocities 1200+fps.

Alloys/coww/range lead + tin are always harder to find a sweet spot compared to pure lead/tin.

I've cast/used/shot nothing but outdoor range lead for decades & it seems to work without adding tin if I keep the speeds in the 900fps to 1100+ fps range, depending upon the bullet/hp design.

The range lead that I use comes out around 10bhn consistently. I also seperate some of the scrap lead before smelting into cast boolits (hard alloy) & jacketed bullets/22's/swaged lead boolits (soft alloy). I'll use the softer alloy (8bhn) for slower hp's & wd the harder alloys (12bhn after wd) for the faster hp's.

I currently shoot/test hp's in 38spl's/357mag's with a 2" bbl, 4" bbl's (3), 6" bbl's (4), 8" bbl's (2) & a 10" bbl.
Not as many 44's but I currently use a 2 1/2" bbl, 6"bbl, 8" bbl & a 10" bbl. But I have tested cast hp's in a 4" bbl, a ruger 44 auto-mag & a marlin 1894.

Some interesting reading about alloys, hp's & how they performed @ different speeds with pictures.

Expanding bullets (hp's) in the 44

http://www.goodrichfamilyassoc.org/44_Special_Articles/44%20spl%20-%20may%201953%20american%20rifleman.pdf

The 44 vs 357 with speeds/hp expansion tests

http://www.goodrichfamilyassoc.org/44_Special_Articles/44%20spl%20-%20oct%201953%20american%20rifleman.pdf

Some of the hp's I cast/test
1. ness 30cal safety slug/huge hp
2. mihec 503 clone 3 different size/shaped hp's
3. 44spl/mag hbwc
4. 38spl/357 hbwc
5. mihec 359-640 2 different shaped hp's
6. mihec 452-200 2 different shaped hp's

87527

The latest hp's, haven't done any testing yet (strait range lead/ 10bhn air dropped) for a 9mm, 2 different hp's.

87528

Mihec's hbwc cast boolit for the 44's. Had to use the (soft) separated range scrap for an alloy to get these to expand in a 2 1/2" bbl'd revolver reliably @ just over 800fps.

87529

[GP100man]

As I understand the affects of Sn on lead it helps relax the surface tensions & helps bonding of the crystaline structures .

I`ve found as you have , Sn makes the boolit tuffer without the brittleness.

This is how my febile mind precieved Sn affects on lead after speakin with a metalurgist.

[375RUGER]

Get Roto Super Tough Babbit instead of tin and you can mix a real good HP alloy with WW. Or add Cu to your pure tin and you don't have to add near 6% to get good toughness and ductility.

[alamogunr]

Some interesting reading about alloys, hp's & how they performed @ different speeds with pictures.

Expanding bullets (hp's) in the 44

http://www.goodrichfamilyassoc.org/44_Special_Articles/44%20spl%20-%20may%201953%20american%20rifleman.pdf

The 44 vs 357 with speeds/hp expansion tests

http://www.goodrichfamilyassoc.org/44_Special_Articles/44%20spl%20-%20oct%201953%20american%20rifleman.pdf
87529

Any ideas why these won't print? I would like to save for future.

[Airman Basic]

Any ideas why these won't print? I would like to save for future.
Right click "save image" then open in your fav pic app.

[alamogunr]

Thanks! Actually I didn't get "save image" when I right clicked. I just clicked on "save as" and it went directly to my "downloads" and I printed from there as a PDF.

Not real sure about it but that is what it looked like.

[fredj338]

Toughening the alloy is a good description. Antimony makes an alloy hard, but brittle. For most of my LHP, it's 25-1 for under 1000fps & 20-1 up to 1250fps or so. The HP design also has a lot to do with it. A cup point can alloy a softer alloy & not lose much mass.
http://img.photobucket.com/albums/v703/fredj338/DSC_0041.jpg (http://smg.photobucket.com/user/fredj338/media/DSC_0041.jpg.html)