Hardness drop after PC

ChiliDawg

ChiliDawg

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I’m experimenting with PC and comparing it to traditional lubing and sizing. I noticed that the hardness has drop significantly after Powder Coating. Mind you I am using a Lee Hardness checker but it should be close. Water dropped bullets come out at 16.6 BHN and PC bullet is coming out at 9.8 BHN. How can I bring the hardness back up?
I am only shooting low pressure loads for bullseye competition.
 
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Heat slower and cool faster. I find preheating my oven or not having it at temp makes it put out too much heat to get there. I dump my bullets into water after coating as well. Aside from making sure they aren't too soft or way too hard I pay very little attention to hardness otherwise. I have used my lee tester 2-3 times. My fingernails tell me with enough accuracy for the pretty varied cast bullet shooting I do.
 
Isn't the point of the powdercoat to act as hard jacket? Especially for low velocity hole puncher loads, do you need the hardness in the lead? I'm not being facetious, i'm genuinely asking, i'm probably gonna start casting soon.
 
The PC is a seal. It prevents hot gasses from slipping by and vaporizing lead, which leads to leading. Its durable but it's properties are not even close to gilding metal or copper.
 
There was a thread on this about a year ago that has some good information:
https://www.canadiangunnutz.com/forum/threads/quenching-cast-bullets.2526808/

The curing temperature will absolutely affect hardness of the lead alloy. There are competing mechanisms of hardening and tempering going on. The best results will be if you can get hot enough to dissolve the alloying elements that enable the age-hardening reactions. Problem is, that risks burning your coating. Next best is to keep temps as low as possible, so the tempering reactions are kept modest.
 
fingers284 said:
Shmoo has the correct question here, the powder coating takes all the fussing about slug hardness out of the equation...quite simply...it (hardness) dont matter anymore.
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Like I said, I pay little attention to hardness. I have lots of applications where it definitely matters though. PC can protect from the lead from flame cutting but it won't stop integrity issues with high-pressure or high-velocity rifle loads you expect anything resembling accuracy from.
 
ChiliDawg said:
I’m experimenting with PC and comparing it to traditional lubing and sizing. I noticed that the hardness has drop significantly after Powder Coating. Mind you I am using a Lee Hardness checker but it should be close. Water dropped bullets come out at 16.6 BHN and PC bullet is coming out at 9.8 BHN. How can I bring the hardness back up?
I am only shooting low pressure loads for bullseye competition.
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Water quench out of the oven after PC
 
BLCB said:
The PC is a seal.
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Isn't PC just a replacement for regular lube, mainly to reduce or stop leading of the bore, though it no doubt adds to the sealing effect.
The lead still has to obturate to fill the groove to make the majority of the seal. In that regard hardness is still important to balance with pressure/velocity.
I'd like to see the science as to the degree of any affects
 
Leading comes from gasses slipping past the bullet, vaporising and subsequently depositing the lead into the barrel.

My understanding is that obturation is desirable with "lubricated" bullets to aid the lube, which is primarily acting as a seal against the gasses. It's why some lubes hold up much better than others.

A tighter fit means the gasses have to work harder, giving you the ability to shoot at higher pressures with no leading. PC is such an improvement that none of that matters nearly as much as far as preventing leading.

I haven't cast a bullet in well over a year so some of my understanding could be wrong or confused.
 
ChiliDawg said:
I’m experimenting with PC and comparing it to traditional lubing and sizing. I noticed that the hardness has drop significantly after Powder Coating. Mind you I am using a Lee Hardness checker but it should be close. Water dropped bullets come out at 16.6 BHN and PC bullet is coming out at 9.8 BHN. How can I bring the hardness back up?
I am only shooting low pressure loads for bullseye competition.
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It would help to know what it is you are loading for. I use either a 50/50 mix of clip on ww and pure or pure with tin all pc air cooled out of 38/357, 44 special or magnum cases and 45 Colt. Up to 1000 fps with no leading.
 
ChiliDawg said:
I’m experimenting with PC and comparing it to traditional lubing and sizing. I noticed that the hardness has drop significantly after Powder Coating. Mind you I am using a Lee Hardness checker but it should be close. Water dropped bullets come out at 16.6 BHN and PC bullet is coming out at 9.8 BHN. How can I bring the hardness back up?
I am only shooting low pressure loads for bullseye competition.
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You are kind of comparing apples to oranges. By water dropping your cast bullets you are essentially case hardening them. To get a true comparison you need to compare a non-water dropped cast bullet to a non water dropped PC'd bullet. Conversely, you could compare your water dropped cast bullet to a water dropped PC'd bullet. I'm guessing that in both cases the BHN of the cast bullet and the PC'd bullet will be close.

Aside from that, a 9.8 BHN is plenty hard enough for target velocity handgun loads. Remember that swaged lead wadcutters are essentially just lubricated lead bullets yet they create only minimal leading and give excellent accuracy. You also want bullet obturation to create a good gas seal so a softer alloy is, in fact, desirable. The PC prevents the surface of the bullet from shedding lead in the bore so in effect you get the best of both world from PC'ing, i.e. good bullet obturation but minimal to no leading.

The hardness of the alloy might be a more critical factor in high velocity rifle rounds but for the target velocity handgun rounds you are concerned with hardness is a less critical variable.
 
BLCB said:
The PC is a seal. It prevents hot gasses from slipping by and vaporizing lead, which leads to leading. Its durable but it's properties are not even close to gilding metal or copper.
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While to a large degree I concur with you I have read reports of rifle shooters exceeding well over 2000 fps with PC'd bullets and experiencing no leading so it is pretty tough stuff. Interestingly, Berry's Bullets (which are copper plated, not jacketed) are advertised as not for use exceeding 1200 fps which is far below what some PC'd bullets are achieving.
 
I can see it wasn't exactly clear but I was talking about a proper jacket of either metal as opposed to plating. Federal fusion bullets are copper plated which is why I included it with gilding metal.

I have pushed both plated bullets and PC over 3000fps as a test and shoot 2500+ loads fairly regularly. With plated bullets minding your crimp (don't apply any more than you need to produce a very faint ring) and using cartridges with enough volume to keep pressure under 40-45kpsi helps immensely. .308W with 85grn bullets for instance. With PC bullets hardness becomes critical and pressure doesn't seem to matter as long as your application is proper.

I took a lot of gophers with cast .223 over the years. PC let's you push them pretty hard.
 
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