PC Velocity Expectations

Hey everyone, I loaded up a batch of PC'd 113gr lee soup can bullets with increasing charges of Accurate 2495 today to see what the most velocity I could get from my pc'd bullets was. Load 1 was 5 cartridges with a 30gr, load 2 was 5 cartridges of 31 gr, etc. I shot until there was noticeable leading. 30 gr went well, I got in between 2071 and 2250 fps, 31 gr was 2220-2300 fps, load 2 was 2295-2300fps. Load 1 had no leading, load 2 had minor leading on the rifling, and load 3 I noticed larger leading deposits in the lands. I am using an air dried wheel weight alloy, but there is a substantial amount of stick on wheel weights in there, so probably a little softer than regular ww's (sorry, no BHN tester). I'm curious, what kind of velocities is everyone else getting? How far can you push pc'ing?

Alloy fails before the PC.

I have run some 6mm 87 gr pced to 2980's accuracy wasn't super great but sure didn't take long to reach far end of range. Popper is correct in alloy will fail first before PC. Using jacketed data I get from 150 to 350 fps faster velocity than book data for velocity on a given load. an arsenal 200 gr 308 bullet will go high 2700 to low 2800 fps which should be good for longer ranges. They are real thumpers on both ends

To answer your question of how fast? I don't know, but I have fired a number of plain base PC in my 22-250 exceeding 3500 fps with no signs of leading. I did not chronograph, the accuracy wasn't there but it proved to me the polymer jacket can withstand that kind of velocity.

To test the limit i have wet coated some 55 grain lead cores (.185") and swaged them to .224 and loaded them in .223 the load would give a jacketed bullet over 3000 f/s . There was no leading but accuracy was terrible as my dies designed for using 22 rimfire cases as jackets left a burr on the bullet base. Later i took the anvil from a spent large primer and swaged the core into it they did shoot much better. The cores were wheel weight alloy .

2700 with 2 moa acuracy for 10-shot groups @ 100yds.
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Alloy was 4 parts range scrap 1 part mono-type. 1 coat of shake & bake pc/john deere green from smoke. Used bore-tech eliminator to get the black streaks out of the bbl. No leading

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Used bore-tech eliminator to get the black streaks out of the bbl. No leading

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OK. That answered the first question to pop into my mind. The black streaking is carbon fouling then.

Did you do anything to harden the boolits such as quenching?

What is mono-type? I've heard of linotype.

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What is mono-type? I've heard of linotype.

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Lino & Mono type are both lead based alloy used in the printing industry to make type / characters for printed material. Linotype basically consist of 4% tin, 12% antimony, 84% lead with a BHN of around 19 while Monotype consist of 9% tin, 19% antimony, 72% lead with a BHN of around 25.

Linotype basically means line of type, it was set on a machine that replicated / cast an entire line of type as it was typed on a keyboard called a slug, once the printed job was finished the type was remelted and used again. The Monotype machine which is similar to the Linotype machine cast individual letters / characters instead of a single line of type. Monotype lead is much harder and will last much longer and was used for printing jobs that would normally be repeated multiple time. If the job required changes since the Monotype machine cast individual characters only the characters that changed needed to be set and replaced instead of the whole block of type like with the Linotype machine.

When I got into the printing industry back in the late 70's both of these printing process were pretty much phased out but I acquired a good bit of both Lino an Mono type being in the industry, it's pretty hard to come by these days in it's original form but both are still around. We have four old letterpress's at work but they are mainly used for die cutting, scoring,perfing an numbering all the printing is done on modern presses.

The only thing I do is water quench the bullets when they are 1st cast. I so this simply because I don't want the bullets hitting each other and distorting each other.

I don't do anything to pc'd bullets other then let them air cool.

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I don't do anything to pc'd bullets other then let them air cool.[/QUOTE]

Correct me if I'm wrong, but that's because pc'ing them in an oven will anneal them, correct?

When the bullets come straight out of the oven the coating is still soft. Some do a water drop to increase the BHN. Since I am casting for handgun I don't need an higher BHN and since I stand all my bullets it is not a problem for me. My oven is on a timer and is allowed to cool down undisturbed unless I am coating more that a thousand and need to shift trays.

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Originally Posted by thirtythirty

Correct me if I'm wrong, but that's because pc'ing them in an oven will anneal them, correct?

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Basically it goes like this give or take a few BHN depending on the alloy used and if the alloy used responds to water quenching or heat treating.

1. If you air cool your bullets when cast then PC them an allow them to air cool again the second time there is no change in the as cast BHN of the bullet.

2. If you air cool your bullets when cast then PC them and quench them right out of the toaster oven they will gain a hardness of about 75% over the as cast BHN.

3. If you quench your bullets out of the mold to begin with then PC them and allow them to air cool they will soften around 50% from the original first quenching BHN.

4. If you quench your bullets out of the mold to begin with then PC them and quench them right out of the toaster oven a second time you only loose around 15% hardness from the first quenching.