openbook
09-15-2022, 09:19 AM
Over in the Coatings and Alternatives subforum, I found this interesting discussion about pushing PC'ed (and double-PC'ed) boolits to maximum velocities. The thread was named Can you just PC and (almost) forget about BHN?
The professor calculated a .003" thermoset polymer build out would resist the torque spin up of 50k psi chamber pressure of a 30/06 i inquired about.
I single PC my handgun bullets, but if I am loading full power loads I do a partial cure, double PC. I have found PC to be stable at in full power loads 30/06 loads as well as 3500+ fps in a 22-250. I personally find it amazing we can create a polymer bullet jacket in the first place and second that it works so well.
This is really interesting to me and I want to ask a related question.
The idea that we can take a copperless bullet and coat it to maximum pressures and velocities over 3000 fps is amazing. I've noticed that over on LASC, they make the same claim for oven heat-treated alloy—without PC. I've searched around castboolits the past couple days and read probably 15 threads, but I haven't been able to find one that squarely addresses this claim. So, if anybody is interested, this is on the Cast Bullets Notes page at LASC. Scroll down about halfway and there's a table, Approximate "Maximum" Chamber Pressure for Lead Alloys (PSI). On this table the highest pressure category is Oven Heat Treated Wheelweights, and the claim is
"55,000 [psi] - Jacketed velocities in handguns and rifles with quality bore and balanced load." No mention of a gas check, I might add. The site claims WW (of appropriate antimony content) can be heat treated to over 30 BHN.
Is this realistic? "Jacketed velocities," let's just say 2750 fps, to be reasonable. With no PC and no GC. I solicit your thoughts.
The professor calculated a .003" thermoset polymer build out would resist the torque spin up of 50k psi chamber pressure of a 30/06 i inquired about.
I single PC my handgun bullets, but if I am loading full power loads I do a partial cure, double PC. I have found PC to be stable at in full power loads 30/06 loads as well as 3500+ fps in a 22-250. I personally find it amazing we can create a polymer bullet jacket in the first place and second that it works so well.
This is really interesting to me and I want to ask a related question.
The idea that we can take a copperless bullet and coat it to maximum pressures and velocities over 3000 fps is amazing. I've noticed that over on LASC, they make the same claim for oven heat-treated alloy—without PC. I've searched around castboolits the past couple days and read probably 15 threads, but I haven't been able to find one that squarely addresses this claim. So, if anybody is interested, this is on the Cast Bullets Notes page at LASC. Scroll down about halfway and there's a table, Approximate "Maximum" Chamber Pressure for Lead Alloys (PSI). On this table the highest pressure category is Oven Heat Treated Wheelweights, and the claim is
"55,000 [psi] - Jacketed velocities in handguns and rifles with quality bore and balanced load." No mention of a gas check, I might add. The site claims WW (of appropriate antimony content) can be heat treated to over 30 BHN.
Is this realistic? "Jacketed velocities," let's just say 2750 fps, to be reasonable. With no PC and no GC. I solicit your thoughts.