Heat-treat got my boolits REALLY hard

[mroliver77]

In my toaster oven there is nothing between the heating element and the rack. Most need some kind of barrier or heat sink to buffer the heat when the element is red hot or overheating of alloy will occur. Many fix a sheet of 1/8" steel below the top element and/or above bottom element depending on the model. I use a plate on the rack to help smooth the heat fluctuations from cycling off and on.
For maximum heat treating use the slump method to adjust oven. Different alloys need readjusting maximum temperature. I try to use the least amount if antimony possible and rely on maximum heat treating to get the hardness desired.
A hard, tough .30 cal boolit with a 50% or better meplat, driven at 2200+ fps, will leave a
1"+ wound channel in a deer or hog and also drive deep into vitals. I personally like to drive them faster to flatten trajectory and reduce guestimating errors.
In my M1 Garand I was using the 311413 boolit hardened to 28 brinnell pushing it 2400fps and getting 4"-5" groups(8 shot) at something like 130 yards to one steel target we have set up. I wondered why I could not get it better than this grouping. I then read that this boolit does not shoot well past 1600fps or so. I figure that the extreme hardness helped to support the pointy nose section and boolits were as fat as would feed reliably. I had a point in mind about the M1 loading but it must have been b.s. as it is gone. lol
Anyhow, I would have tried them. Just possibly you might have stumbled on to an accurate load if nothing else.
Jay

[kelbro]

I did shoot some of them. Full power loads. 31gr of 3031. Shot 2-3" at 100 with buckhorn sights and 50 year old eyes. Not too shabby. No leading.

[243winxb]

The higher the % of antimony, the faster the alloy will harden after heat treating/water cooling.http://www.keytometals.com/page.aspx...site=ktn&NM=88

The alloy containing 2% Sb clearly does not respond sufficiently to be considered as a possible alternative. The 4% Sb alloy, however, attains a hardness of 18 HV after 30 min, and the alloys that contain 6, 8, and 10% Sb could be handled almost immediately

[MtGun44]

+1 on what Bret said - but for me it is in the mag pistols.

Bill

[nanuk]

Ok. Some questions
WRT HT WW alloy (I love acronyms)

1) HT WW and after ½ hr, WQ. Gets them HARD. The higher the temp, the harder. Does water Temp make a difference?


2) Heat WW up to near melting and let rest to cool slowly in OVEN will remove ALL temper and make dead soft ?(well, as dead soft as the alloy can be?)


3) even the hardest alloy will squash in a vice. May take more effort but will show little? Would taking a HT boolit and hammering it with a a 3# hammer cause it to shatter? Could this be a test for “Brittleness”?

4) is there a way to “Flash” heat a boolit to harden only the surface, if harder is needed for a specific gun, but keep the internal metal softer/tougher for less fragmenting upon impact?

5) when softening the Nose, does it need to get hotter than when it was HT, or just as hot, and then slowly cooled?

6) can one soften noses by setting up a shallow pan of water in hot oven, bring to temp, then allow to slowly cool? (all the while ensureing the water level stays near optimum level?

7) does HT make a boolit brittle? if HT to same hardness as Lino, will it be as brittle?