BHN Number

[JEBar]

in another thread, this link was provided ==== http://www.acmebullet.com/bullets-reloa ... uct_id=446 ==== as can be seen they note this 45-70 500 Grain RNFP - COATED bullets are hard cast bullet is cast with 92-6-2 certified alloy (BHN 16) .... I know BHN = Brinell Hardness Number .... but, for example, I don't have a good understanding of just that a BHN of 16 really means .... is it a lead bullet that will mushroom quickly ? .... will it not mushroom and penetrate deeply ? .... comments from anyone who does understand this scale would be appreciated ....

[Squatch]

My impression is that a BHN of 16 is a moderate hard cast bullet. I've been using Missouri Bullet Company's Hard Cast bullets of around BHN 18 with no leading in both my 44 mag and 45/70. But I'm keeping speeds moderate. As in under 1,250-1,400 fps.

My understanding is that a BHN of 12-14 is for specials and speeds under 900fps.

BHN of 18 for light magnum loads. As in 44 mag not 458 win mag.

500 gr bullets aren't really for expansion. They tend to penetrate deeply.

http://missouribullet.com/technical.php

The best info out there is the Lyman cast bullet manual. If loading lead you should have it.

[JEBar]

My impression is that a BHN of 16 is a moderate hard cast bullet. I've been using Missouri Bullet Company's Hard Cast bullets of around BHN 18 with no leading in both my 44 mag and 45/70. But I'm keeping speeds moderate. As in under 1,250-1,400 fps.

in the info given they state that with the coating they use, muzzle velocity can increased without any issue

BHN of 18 for light magnum loads. As in 44 mag not 458 win mag.

makes me wonder about what hardness would be best for a 45-70 .... as you noted, Missouri Bullet Company shows a BHN of 18 for its coated bullets

500 gr bullets aren't really for expansion. They tend to penetrate deeply.

that's part of my confusion, I would have expected a higher BHN in a bullet designed for penetration

The best info out there is the Lyman cast bullet manual. If loading lead you should have it.

I have one at home in NC and couldn't agree more as to it being an excellent info source

[Squatch]

18 is a pretty hard bullet. You are not going to dig your thumbnail into those. Especially the coated ones.

I haven't recovered any fired ones so can't say what they look like after impact.

I know they will put a hurtin' on regular plate steel that's not hardened out of both the 44 and 45/70.

I'm beginning to dislike the term "Hard Cast". It covers way too much territory these days. I've got bullets from a local caster labeled as hard cast and they are quite soft and lead badly in my 44's.

[JEBar]

the 500 gr is what really caught my attention .... 405 is about the largest I've seen from most companies .... the heaviest jacketed 45-70 bullets I've seen are 400 grain'ers from Barnes and Sierra .... I'd sure like to see a 500 jacketed

[clovishound]

With coated, the hardness is not much of an issue in my understanding. The only time I have had trouble with leading in coated, is when either the coating was very fragile, or if I cut the coating with an overly aggressive crimp, or not enough flare.

Not sure how much expansion you would get with a non hollow point profile regardless of hardness.

[JEBar]

good points and an excellent question .... in continuing to read about barrel leading, I found this most interesting quote from the Missouri Bullet Company :

"A common conception is that when it comes to lead bullets, harder lead equals less leading. This is a false perception!"

their most interesting explanation can be read at this link === https://www.missouribullet.com/technical.php===

[JNG3]

Check out the good folks at the castboolit forum. They can steer you in the right direction. BHN is the hardness of the lead alloy. 16 BHN is useful for magnum revolvers and some rifles. However size is far more important than hardness. You should slug the bore to find the exact diameter. Than go .001 to .003" over the groove diameter. The type of lube can be critical as well. Don't get hung up on BHN only, there are other factors at play that matter just as much if not more than simple hardness!

[DAVIDF]

JEBar,

Yes, lots of information at castboolit forum. Also at Beartooth in their FAQ's http://beartoothbullets.com/faq/index.htm.

A BHN of 16 would not be considered very hard and probably not the best for really large game. But, if you harden with the wrong alloys, then it is also too brittle. Beartooth talks about using an alloy with a low antimony content of only about 3% and heat treating to a BHN of 21 to 22. They claim that results in a bullet that is hard but not brittle.

But, a softer bullet can give better accuracy than a harder bullet if both are not sized properly for the firearm. It takes about 22k psi for the 16 BHN bullet to obturate while the 22 BHN bullet takes about 31k psi. At least that is the theory, nothing that I have scientifically proven

Based on my limited trials, a properly sized bullet can give you great accuracy and limited leading with not a lot of work.

As an aside, I think plated bullets, especially in larger bores could probably work really well on lots of fairly large game. I am basing this on terminal ballistics testing of plated shotgun slugs and buckshot. Even though the plated slugs and buckshot are a very soft alloy (or perhaps pure lead) they perform significantly better in terminal ballistics testing than the non-plated slugs and buckshot. A plated slug will perform about as well thru an extremely hard barrier such as safety glass. They penetrate about the same in organic ballistic gelatin as a hard cast slug from Brenneke after passing thru a windshield (which is extremely hard on bullets) with great weight retention. Non-plated slugs don't retain much weight even in bare gelatin.

[DAVIDF]

I still think you need to try these http://beartoothbullets.com/open_sight/ ... ght.htm/21 in your .45-70 and let us know the results. 1600 or 1700 fps with a 525 gr bullet is quite a bit. They claim they designed them to work in a Marlin 1895. Should work great in your Henry.