BHN - Why the Large Disparity?

[Recruit]

Missouri Bullet claims a BHN of 18 for magnum velocities. Fortunecookie45lc indicates a BHN of 18 for velocities between 950-1700fps. Yet, a BHN of about 11 seems popular for these velocities on this forum.

I realize one must see what works for their gun and application. Small differences could also just be preference or whatever metal/alloy you happen to have on hand. But a large difference...what am I missing?

My gun and intended application is a Rossi 92 in 45 Colt at +P velocities (1300-1400fps) for whitetail hunting out to 125 yards. Should my bullets have a BHN of 18 or so for this scenario?

[454PB]

You can use 11 BHN for your planned velocities, but everything has to be right. I've done it, but because I have a good supply of "hardening" alloys, I usually use a BHN around 18 for such velocities. You may also want to do some heat treating of the softer alloys if you don't have access to hardening alloys.

[C. Latch]

What is a fortune cookie 45lc?

[geargnasher]

It isn't that simple. Fit, as we often say here, is KING. Fit, however, is more of a dynamic thing than a static thing when discussing how a bullet fits the gun at different points in the firing event. Powder charge and burn rate, alloy hardness and composition, initial bearing surface size, and nose shape all come in to play, and are all variables dependent on each other. See what I mean? There is no "X bhn for Y velocity or Z pressure level". Much of the time, I get better accuracy when "bumping" the alloy up, meaning I load so the powder hits the bullet harder than it can withstand and it then swedges to fit the gun exactly. If you're up into the mid 20s with pressure, with the large surface area of the .45 bore, you may find softer alloy down around 11-14 bhn will do fine and may shoot better than 18 bhn ones. Softer will also do MUCH better as a hunting bullet, so I'd shoot as soft as I can get away with accuracy-wise. If you size them the way your gun likes and use the right powder to work with the alloy, it won't lead and won't "strip" the rifling, no how, no way. If you don't cast your own yet, now is the time to start!

Gear

[jmort]

Fortune cookie 45 = YouTube

[geargnasher]

You can use 11 BHN for your planned velocities, but everything has to be right. I've done it, but because I have a good supply of "hardening" alloys, I usually use a BHN around 18 for such velocities. You may also want to do some heat treating of the softer alloys if you don't have access to hardening alloys.

I agree that heat-treating "softer" alloys probably makes the best combination of hunting performance and accuracy that one can achieve, better actually by far than simply alloying up to the hardness desired. Heat-treating is a different kind of toughness altogether than simply adding hardening metals.

Gear

[Recruit]

Most of my lead (premelt) is at a BHN of 10-11 according to Staedtler pencil testing. For the first casts (ever), I'll probably shoot for a BHN of 13-14 using the alloy calculator on this site and see how it goes. Figure a smidge of pewter, air-cooled and aged for a week or so should do it. Thoughts?

Agree that staying on the softer side for whitetail hunting would be best.