A question about max pressure listings

[DeplorabusUnum]

I cast for a few different calibers and check the BHN with the Lee hardness tester. I've always tried to keep the listed max pressure for my lead just at or below the expected pressure listed in the manual.

I recently picked up a 629 and am loading some ammo for it.

Lyman manual lists the following loads and pressures for a 44 Magnum Linotype 240 gr RF bullet:

Unique 11.7 gr with a listed pressure of 37,900
2400 20.6 gr/38,900
H110 23.5 gr/35,700

Linotype has a BHN around 18-20. Even at 20, the listed max pressure in the Lee Hardness table is 25,700 psi.

So it would seem that according to Lyman's you can exceed the maximum pressure of your lead without a problem. I assume since the loads are tested and printed by Lyman it's safe. I'm sure lot's of you have shot these kind of loads in your 44Mag pistols. Any issues arise from exceeding the pressure limit of your lead. Is it more likely to cause leading? Just trying to figure out if I need to cast harder bullets for these magnum loads.

Any comments appreciated.

 

[reddog81]

Linotype has a BHN around 18-20. Even at 20, the listed max pressure in the Lee Hardness table is 25,700 psi.

I wouldn't worry about it that much. I shoot 9mm at higher pressures with much softer bullets than that on a regular basis. I've read much more from people who disregard the Lee hardness table versus people who use it as a reference. Most people wouldn't shoot pure linotype even with max loads.

 

[DeplorabusUnum]

I wouldn't worry about it that much. I shoot 9mm at higher pressures with much softer bullets than that on a regular basis. I've read much more from people who disregard the Lee hardness table versus people who use it as a reference. Most people wouldn't shoot pure linotype even with max loads.

Thanks. Kind of what I thought. I don't shoot pure Linotype ever, just use it to add a little hardness and a little tin.

 

[rockquarry]

If you have good bullet fit, a pretty soft bullet can be used without any leading problem.

Some years ago, the editor of the Cast Bullet Association magazine mentioned something to this effect in an editorial: the softest bullet that can be fired at the desired velocity without leading the bore will almost always provide the best accuracy.

This, of course, requires experimentation, but serious bullet casters know all about that. The editor was referencing rifle loads, but I think the same would apply to handgun cartridges as well. There are exceptions to everything, but I've always found this to be generally good advice.

 

[DeplorabusUnum]

If you have good bullet fit, a pretty soft bullet can be used without any leading problem.

Some years ago, the editor of the Cast Bullet Association magazine mentioned something to this effect in an editorial: the softest bullet that can be fired at the desired velocity without leading the bore will almost provide the best accuracy.

This, of course, requires experimentation, but serious bullet casters know all about that. The editor was referencing rifle loads, but I think the same would apply to handgun cartridges as well. There are exceptions to everything, but I've always found this to be generally good advice.

Thanks for responding. Whoever said size doesn't matter?

 

[fredj338]

You are over thinking this a bit. If your lino bullet is the correct size, you cant over drive it in a 44mag imo.

 

[mtgianni]

The Lee hardness table and kit are done by one mechanical engineer's theory. As was stated hardness is way down the list from fit.

 

[mikld]

I have cast and reloaded for my 5, 44 Magnums since '89. I tried the "BHN vs pressure" formula but found it was just so-so. My main concerns are #1, bullet to gun fit, #2 decent lube, and lastly (#8?) BHN. I have driven my cast 240 gr LSWC to 1,400 fps through my Ruger SBH and Dan Wesson 44H with decent accuracy and minimal (no) leading using Wheel Weight alloy (BHN approx 12) with C-Red lube. In haven't run any SWCs over my chrony when fired from my 20" Puma, as I normally use a different bullet in it (Ranch Dog 265 RNFP w/check). But all my cast bullets are sized to fit the gun...

 

[DeplorabusUnum]

There seems to be a consensus building. SIZE, SIZE, SIZE.

 

[fredj338]

There seems to be a consensus building. SIZE, SIZE, SIZE.

With revos its more complicated than just matching bore dia + 0.001". You have 5-6 cyl throats & all can be diff dia. So I measure throats & if they are smaller than bore, they get opened up. It makes no sense to run a 0.430" bullet thru a cyl throat that is 0.429".

 

[mtgianni]

Well to a point. As a friend says "Lube doesn't matter until it does". In essence until lube makes a difference in your groups you need to be already under 1.5 MOA. He is also shooting lead pc'd at near 3000 fps out of a 223 single shot. That "lead" is one of the hardest babbit bearing alloys ever. Hardness has a relationship to accuracy but that barrel will also shoot MOA with ww alloy at 1600 fps. To make an analogy, You can build an engine & gearing that will make a 1962 Ford Falcon run at 150 mph but it still won't win the Indianapolis 500.

 

[mikld]

FWIW; All my revolvers use cast bullets sized to fit the cylinder throats, so that they fit the gun. Bullet to gun fit is much more than slugging a bore and using bullets .001" larger than the groove diameter. Many of my semi-autos use bullets that when loaded fit the gun's chamber/throat. More than just slugging the barrel to find the groove diameter. I would rather just say "fit the gun" than go through an explanation of my methods and why I use them...

 

[DeplorabusUnum]

FWIW; All my revolvers use cast bullets sized to fit the cylinder throats, so that they fit the gun. Bullet to gun fit is much more than slugging a bore and using bullets .001" larger than the groove diameter. Many of my semi-autos use bullets that when loaded fit the gun's chamber/throat. More than just slugging the barrel to find the groove diameter. I would rather just say "fit the gun" than go through an explanation of my methods and why I use them...

So I was curious and just slugged the barrel on my 25-2. The groove diameter is .451. My throats all measure .455. I have a .452 sizer, and a .454 sizer. I'm hearing you say you would use the .454 sizer. Is that a correct assumption?

 

[mikld]

So I was curious and just slugged the barrel on my 25-2. The groove diameter is .451. My throats all measure .455. I have a .452 sizer, and a .454 sizer. I'm hearing you say you would use the .454 sizer. Is that a correct assumption?

PMed, I hope...

 

[pistolpete10]

I've shot a lot with lino as per Lyman's loads, 245 lino bullet(it doesn't weigh 245) with 296 and 2400 powders. The 2400 loads were higher than what they give you now. The 2400 loads were the most accurate handgun loads I've ever fired, gun was a NM Super Blackhawk. Leading was not a problem.

 

[dogdoc]

So I was curious and just slugged the barrel on my 25-2. The groove diameter is .451. My throats all measure .455. I have a .452 sizer, and a .454 sizer. I'm hearing you say you would use the .454 sizer. Is that a correct assumption?

That’s what I would do. The problem may be that your bullets do not drop that large from the mould. You may have to load hot enough if safe to get bullet to obturate in cylinder throats in order to get good accuracy . That is what I do in my colt saa with .455 to .456 throats. You also have to use a soft enough alloy. These commercial hard cast pistol bullets are way too hard and lead horribly due to poor lube and gas blow by. (They will not obturate unless magnum pressures are obtained).When I use commercial hard bullets I coat them with Lee liquid lube and that usually reduces leading . A good load for my handguns is one that will put 5 or 6 in two inches or less from bench at 25 yards