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''Does Cast Bullet Hardness change after Powder Coating?''

2K views 11 replies 6 participants last post by  fredj338 
#1 ·
#2 ·
interesting info, never gave it much of a thought.

coating, for me, was to be able to run my standard hardness "as cast" bullet alloy of around 11-12 BHN, that I used strictly for target velocities to minimize leading, at higher "practice defense load" velocities to.....well....prevent leading.

preventing leading meant more rounds fired between cleanings and cleaning was easier.

sig357fan
 
#3 ·
#4 · (Edited)
ActualLY annealing. Depends on temp & time, but the alloy will soften with baking & air cooling. I water drop mine out of the pc oven, they seem to get about 5bhn harder.
 
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#7 ·
Keep in mind that bhn Will increase after a few days up to a month after water quenching. Also water temp plays into it too.
Fwiw, not a fan of the lee tester. It relies too much on the crappy little microscope & the users manipulation of the process.
 
#8 ·
O.K......let me throw this out there....

why do we coat?
to run lead projectiles a velocities that would probably cause a bare lead projectile to lead the barrel...agree/disagree?

coating is very thin, heating/cooling how ever done will effect the base metal of a coated object, regardless of what it is.

questions:
does the heating/cooling procedure used to cure PC on a coated bullet have the same effect on a non-coated bullet?

if there is a difference in the hardness between coated/non-coated, is it due solely to the lead alloy used or is it a product of the PC application?

if a solid bullet made only of PC could be made, what would the hardness be?

if a solid bullet made only of PC was then PC'd, would the hardness change?

I know...I know, its one of those pesky "inquiring minds...." thingys....

have at it ladies and gents.

sig357fan
 
#9 ·
Yes the pc adds a little surface hardness. I have tested bhn thru the pc & filing it off the nose.
A softer alloy should not be a problem when coated, but you are still dealing with pressures & alloy failure. So if a pure lead bullet fails at 1100fps, coating it will help but its still likely to fail.
I have smashed plated bullets flat & the plating fails. I have smahed HT & PC flat & the coating is still there intact.
 
#11 ·
I have smahed HT & PC flat & the coating is still there intact.
FWIW, Bayou Bullets is about 12 or so miles from me. I just go down the hiway a bit and pick up my BB. First trip the owner gave me the tour (they were at lunch) and while looking at the operation, he took a bullet, and to show how well HIS coating adhered, he smashed it with a hammer. Flat red 9mm bullet was pretty impressive. He smashed it good and the red coating was still there.
 
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#10 ·
Fred:
define "failure" in regards to how pressure effects the alloy, are you talking a softer bullet will strip in the rifling if the pressure is too high, regardless of coating?

if that's the case, then if the coating is thinner than the depth of the rifling on a softer bullet, then it still can fail.

so we're back to the coating being used as a gliding surface that contacts the rifling, bullet hardness needs to be adequate for the application, the coating sticks to the bullet as it deforms in the rifling so as to prevent leading.
 
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#12 ·
Fred:
define "failure" in regards to how pressure effects the alloy, are you talking a softer bullet will strip in the rifling if the pressure is too high, regardless of coating?

if that's the case, then if the coating is thinner than the depth of the rifling on a softer bullet, then it still can fail.

so we're back to the coating being used as a gliding surface that contacts the rifling, bullet hardness needs to be adequate for the application, the coating sticks to the bullet as it deforms in the rifling so as to prevent leading.
Correct, if you exceed the alloys pressure limits, its gonna skid & accuracy likely suffer. Leading may or may not happen, depends on how much deforming the bullet does.
I have tried water dropped range scrap that was HT & Some PC. The bullets were 130gr in a 6.8. Accuracy of the HT was non existent, barely on notebook paper at 50yds. The PC got me 3" groups at 100. Beyod the 2000fps i was running, accuracy went to crap. So the pc helps but wont fix alloy vs pressure issues. Coatings are a lube, not a jacket. Even plated fail above certain vel/pressure limits. After all, they are also soft lead.
 
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