Little confused over lead bullets in 357 Full Mag loads and BHN Hardness

[Rule3]

I was doing some calculations with the BHN and CUPS and PSI. I want to load some full magnum loads for 357Mag and 44 Mag.

So for just the 357 mag, my MO bullets have a BHN of 18 (hard) but doing the calculations for using say, 2400, H-110 the calculations come out to around 23 BHN?

So does this mean they need to be gas checked? Or am I OCD'ing this?

Anyone using the MO bullets or equivalent hardness for full magnum loads?

I usually just load target loads with HP 38, Unique or Bullseye. Even those pressures calculate over the 18BHN.

Thanks

 

[Jeff H]

I'm one of those who thinks that having the correct size bullet is more important than the exact BHN. Those 18BHN bullets shoot fine for me under full loads of 2400 and don't lead my two 357s enough for me to notice after 100 rounds. I'm happy with it. I don't think I would use anything softer though.

 

[Quoheleth]

Yeah, for some reason in full-house .357 loads the BHN isn't such a factor. I run MB's 158 SWC and 180 FP near full-power and have no problems at all with leading with Unique, 2400 and AA#9.

Now, if you push the softer .38 Special 158 SWC too hot, like +P velocity, I got schmeer from stem to stern out of my SP101. I learned and keep it where standard .38s should be and haven't had a problem since. I use Bullseye, Universal, and Unique for these loads.

Q

 

[Jesse Heywood]

Work up to the max load and check your barrel for leading along the way. When you get to the load that causes the leading back off. If it isn't the max load you desire you will need a harder alloy or gas checks.

The calculations have a whole bunch of variables that are not accounted for. But they do give you a good idea of what can be done

 

[Rule3]

I have shot a few through my revolvers and do not mind a little leading. I just picked up a Marlin 1894 Cowboy so I will be getting a bit more FPS and really do not want to be de leading a carbine barrel.

I am trying out the #1 Ranger 158 gr RNFP. I have some loaded up with my standard 5 grs HP 38 and they chamber perfectly. But it's kinda like shooting a 22LR. Want to get it cranked up a bit.

 

[Walkalong]

Fit is more important than hardness, because with an improper fit it doesn't matter what BHN the bullet is, it will lead. After the proper fit, hardness is the next factor.

 

[fecmech]

I have been running air cooled wheel wts(approx bhn 11-14) for 30 years out of .357 mags and .44 mags. My mag loads run 1200-1300 fps with excellent accuracy and no leading. Fit is where it's at. Best powders for me have been 296/h110, 2400, Blue Dot and WC820(surplus similar to 296/h110).

 

[Rule3]

Fit is more important than hardness, because with an improper fit it doesn't matter what BHN the bullet is, it will lead. After the proper fit, hardness is the next factor.

Agreed, but they is what they is, and the rifle is also I am not into casting my own so I can not size them. The bullets are listed at .358 so should be OK. I have no real need to shoot a lot of full power loads but got to have the big bangs once and a while

 

[Walkalong]

OK, they is what they is then. Question. What size are they (.358), and what size are your revolvers throats and rifles bore? That will help decide what BHN.

 

[GRIZ22]

Keep in mind that when loading warmer loads it is pressure not velocity that is probably the main cause of leading. Different powders have different pressure characteristics. Loaded to the same velocity powder A may lead and powder B is fine.

 

[Walkalong]

The alloy has to be hard enough to grip the rifling without skidding at the velocity you are shooting. The alloy has to be soft enough to bump up from pressure to seal the gases from flame cutting the bullet as it passes through the throats and barrel. The pressure must be high enough to bump the bullet up.

If your throats are .001 or .002 above bore diameter, your bullets fit your throats, and the alloy is hard enough to grip the rifling on its journey while being soft enough to bump up and seal everything, it won't lead at all.

Nothing to it.

 

[Walkalong]

Oh yea. If your bullets are undersized, softer is better until the velocity gets to be more than the alloy can handle. Then you are out of luck.

 

[ljnowell]

I load MO bullets 158gr LSWC over 14.5gr of 2400 in my wifes 686 with no leading problems at all. Its all about the right fit and the hardness.

 

[Rule3]

OK, they is what they is then. Question. What size are they (.358), and what size are your revolvers throats and rifles bore? That will help decide what BHN.

All I meant by that was I can not change the bullets or the bore. I have to go with what I have. With several different revolvers and now the carbine, I can't custom tune a bullet for each one. Yes, there are probably bullets out there with +/- diameter but I have a few thousand of these to shoot up first.

For now I just need to load and go, and see what happens.

 

[243winxb]

CAUTION: USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information. 357mag Alliant 2400-13.0gr 158gr cast .358" diameter. For the 44mag WW296-23.0gr. 250gr cast .430" diameter.

 

[Rule3]

Its all about the right fit and the hardness.

Is that what you or your wife says??

 

[snuffy]

So does this mean they need to be gas checked? Or am I OCD'ing this?

From this statement, I take it that you think just ANY bullet can be gas checked? Not true at all. Gas checked bullets have a rebated shank that allows the gas check,( a shallow copper cup), to be crimped onto it. A plain based bullet cannot be gas checked, there's no place for it to fit.

As for the proposed use of the 18 BHN bullets you have, it's been a while since I messed with .357 revolver loads. My ancient Ruger blackhawk has seen better days, it needs to be re-built. Walkalong has steered you right, (As usual), there should be no reason you can't get them up to magnum levels without much leading.

I've never had sever leading from any of my boolits I cast. A minor gray coating is present at times, but comes right out with normal cleaning with a bronze brush and butches bore shine.

 

[ranger335v]

Mr. Walkalong's last two posts puts more info into a few words than anyone I've ever read.

Don't ignore him about lead bullet speeds, pressures, diameters and alloys.

Maybe add a quality lube tho; the old NRA formula, a 50% mix of allox/beeswax, remains unbeaten, IMHO.

 

[Rule3]

Mr. Walkalong's last two posts puts more info into a few words than anyone I've ever read.

Don't ignore him about lead bullet speeds, pressures, diameters and alloys.

Maybe add a quality lube tho; the old NRA formula, a 50% mix of allox/beeswax, remains unbeaten, IMHO.

I agree with him 110%
The whole original post was about the actual BHN calculations which actually show that with the CUP and/or PSI shown in the manuals the BHN comes out much higher than 18 BHN.

BHN =PSI/1422 So if a load of 2400 is used for a 158gr lead bullet at 15.3 grs that equals 34,000psi. 34,000/1422=23.9 BHN which would be straight linotype or harder. Not a regular mixed alloy. Using the regular CUP formula for BHN then the 18 BHN would only work for loads in the 20-25,000 CUP range.(5grs HP-38 example)

6.5grs of Bullseye produces almost the same PSI as 15 grs of 2400 (one of the fastest to one of the slowest powders)

As to the gas check, yes I did not word that correctly, I know that they can not be just "added" on. I should have said to use gas checked bullets.

 

[243winxb]

OCD1 , you understand the BHN to PSI correctly. If your going to run at maximum, you need a very hard bullet and/or a gas check. High pressure is Not your friend when using cast bullets.

357mag Alliant 2400-13.0gr 158gr cast .358" diameter. For the 44mag WW296-23.0gr. 250gr cast .430" diameter.

The loads i listed above chronographed @ 1254fps -357mag. , 6"bbl. The 44mag did 1339fps, 8 3/8" bbl. Averages

 

[Walkalong]

All I meant by that was

I understood. Since you are stuck with .358, you have to try to match it to the firearms you have. That is why I asked what size the throats were on the revolver, and what the groove diameter was on your rifle.

I have three old books on casting bullets. (Before the internet got rolling when we had to buy books) They have a ton of info in them and it is where I learned much of what I quote from memory when posting. (Although going from memory can get me in trouble sometimes) I also read G&A every month going straight to the reloading section first. Got Handloader mag for a few years as well.

In my "Bullet Making Annual Vol 1" I have a note I wrote with a BHN to pressure chart. (CUP)

5 BHN = 7110 Yield Strength
6 BHN = 8532 Yield Strength
7 BHN = 9954 Yield Strength
8 BHN = 11,376 Yield Strength
9 BHN = 12,798 Yield Strength
10 BHN = 14,220 Yield Strength
11 BHN = 15,642 Yield Strength
12 BHN = 17,064 Yield Strength
13 BHN = 18,486 Yield Strength
14 BHN = 19,908 Yield Strength
15 BHN = 21,330 Yield Strength
16 BHN = 22,752 Yield Strength

I have seen other charts, but like this one.

One thing to remember is that while the bullet needs to obturate to seal things, the yield strength does not need to be almost as high as the pressure used. It can be a good deal lower. As long as the yield strength is lower than the pressure, it can obturate and seal the throats/bore. Now all we have to worry about is if the bullet is strong enough to hold the rifling at the velocity it will be shot at. BHN doesn't equate directly to that type of strength. Yes, the higher BHN will hold rifling better, but alloy also plays a role in how well it holds the rifling.

So, a low enough BHN to obturate with the pressure we are generating, and high enough combination of BHN/alloy strength to hold the rifling at the velocity we will be shooting.

And of course we need enough lube and a proper lube, naturally.

The three main things we need in a lead bullet

# 1 - Sized properly

# 2 - Proper BHN/Strength

# 3 - Proper lube, and enough of it.

If the bullets are undersized a tad, we might get by with a soft enough bullet to bump up and seal things. If they are undersized a hair and too hard to obturate properly, they will lead a lot, and probably severly.

Some of the good news is many guns have properly sized bores, and throats reasonably well suited to lead bullets. You can always ream under sized throats to the right size, but oversized throats are tough to deal with. If they are way to big, we are mostly out of luck, but again, the good news is that most are OK.

 

[Rule3]

This is what confuses me. The BHN for the 45 ACP bullets (18) is the same as for a 357 Magnum.

Not that I shoot a 155gr bullet in 45 but it is listed with 6.9 gr Bullseye for 19,400 PSI compared to my previous example for the 357 of 34,000 PSI. So something does not compute.

 

[Walkalong]

Basically, 18 is too hard for the pressures generated by.45 ACP, but many folks have good luck with them. 12 BHN would be better suited.

There are no throats to deal with in autos, which is a huge advantage. If the bullets fit the bore of the gun, you can get by with harder than needed bullets. There is no gas cutting because they do not have to pass through throats where obturation is needed, and they are large enough to seal the bore from gas cutting without being bumped up by the pressure. There is no skidding because they are hard enough to hold the rifling.

Try 18 BHN bullets in a revolver generating 19,900 CUP and see what happens.

 

[Walkalong]

For normal loads - 12 BHN is all you need for 99% of the loads we shoot with lead in .45 ACP.

For Major Power Factor loads - 18 BHN to make sure. If your bore is not oversized, these will do fine for full loads, and the higher strength gives us some insurance for the velocity. I would still say 16 is more than enough for any standard pressure .45 ACP Load.

 

[Rule3]

For 45, I have been using the 230 gr RN "Softball" which is 18BHN but I sure do not load them up to max. Guess I need to load them up higher. I just got tired of tweaking OAL for SWC to feed in several different 45"s, 1911's double action and striker fired. I wanted something that worked in all of them.

Thanks for all the info, I appreciate your help.