Ready to PC, few ?

[caliplt]

My PC setup is now all here and assembled. I cast about 10 pounds of Lee 312 155's the other day. Casting used to anger me to no end, but I figured out it is all in the mold temp and a SLOW trickle pour into the mold. Anyways, all I have is HF flat black for now. I'd like to get a copper colored powder if you know of a place to get some.

I have a 16" CMMG AR upper that is said to slug a tight .309. Should I size my projectiles at .309 prior to powdercoating and .311 post? Do I powdercoat with the gas checks on or off? Because I am running (aluminum) gas checks, coating the bases is not important...correct? How many coats are you using and what temp/time are you baking?

How about 9mm? Can I coat everything but the bases, or is it critical?

I'm just looking for some general advice, I'd rather do it right the first time and avoid the trial and error.

Thanks!

[talonxracer]

I would not do any powder coating of bullets with flat black powder. Flat colors are derived by adding crystalline elements into the powder that can be abrasive to the bore. stick with gloss colors. Your best selection of powders are from "powder by the pound".


I have found absolutely no need for gas checks with my powder coated rounds

[boost]

My PC setup is now all here and assembled. I cast about 10 pounds of Lee 312 155's the other day. Casting used to anger me to no end, but I figured out it is all in the mold temp and a SLOW trickle pour into the mold.

A trickle pour sounds way to slow but if its works out well. Every mold is different. Mold cleanliness,Temp , alloy, pour speed, pour technique, sprue plate to mold gap, release agent,etc. Just gotta have the patience to figure what works (and yes I get angry too )

I have a 16" CMMG AR upper that is said to slug a tight .309. Should I size my projectiles at .309 prior to powdercoating and .311 post? Do I powdercoat with the gas checks on or off? Because I am running (aluminum) gas checks, coating the bases is not important...correct? How many coats are you using and what temp/time are you baking?

I believe it's a good practice to size before and after . If my boolits drops within .002 to my target size then I don't size before PC. Anything more should get sized first. I got leading in my .40's that drops @ .405 that I sized after PC.
Not sure how a second coat can be applied. Do you mean how thick? And isn't aluminum abrasive?

How about 9mm? Can I coat everything but the bases, or is it critical?

I coat everything but the bases with 9, 40,& 45 . Works for me. The lower velocities doesn't seem to affect naked bases much. But if shot through a gas system, I'm covering the bases no matter what.

[caliplt]

Got it, no flat black.

I'm using gas checks, because I've heard they are necessary for accuracy, most specifically in the 312 155's. I say this, even though I have yet to shoot anything but 230's out of my gun. I have not heard of anyone calling aluminum gas checks abrasive. Making gas checks from aluminum cans is quite popular. Am I missing something?

In terms of casting...it's working, so I'm continuing doing what I'm doing!

I get sizing before and after PC, but my question is if I should size with a .309 first and .311 post PC? Or should I simply size .311 before and after? I'm going to custom order a .310 some day. I say .309 first and .311 post, so that there is room for the PC.

So short story long...I can get away not coating the bases of my 9mm, but should coat all rifle bases that are not gas checked?

Thanks!

On edit: Just read my notes in my casting book. It says that I should size down to .309 prior to powdercoating and .311 after to avoid losing the coat. Damn! 2 more sizing dies to buy.

[oldpapps]

Thoughts from someone who is trying to learn.

Gas Checks -
I don't like the added expense. I worry about a gas check dangling about inside the case unsupported except by propellant. Aluminum is not an abrasive, aluminum oxide is a good one and contact with air (oxygen) starts raw aluminum building a coating of oxide. Gas check add a 'more' flat base to the bullet, allowing a better/quicker obulation (never could spell that word, or say for that matter). The gas check 'step' inhibits a good seal, thus a gas checked or flat based bullet will both shoot better and lead less.

Proper size bullets -
(Don't jump me for the extreme numbers I'm using, they are only examples)
The bore is .308, the desired bullet diameter is .310, the coating is .0015 (two sides - .003 total), as cast bullet is .312. Coat the as cast bullet for .315, size to .310 and loose/disrupt the coating. Or, size the as cast bullet to .307, coat to .310. Or, size the as cast bullet to .308, coat to .311 and size to .310. As long as the desired size is found and the coating is intact, it is only the process to get there.

Coating the base -
The PC protects the sides of the bullet in the rifling, minimizing lead contact. This is good
The PC can protect the base from pressurized hot gas. To what extent, I don't know. For low/er pressure bullets (9MM - your example) raw lead doesn't lead the bore at normal velocities/pressures. At what pressure/heat point will PC bases stop being protected? Looks like testing time.

I don't think I answered any question but maybe I clarified (or muddled) some.

Load with care and enjoy,

OSOK

[caliplt]

Great info, I appreciate it. Now that the unopened can of flat black HF powder is destined for the trash, what is a good (cheap) powder? I prefer copper colored, but will work with black. Should I coat pre or post check installation?

[talonxracer]

https://www.powderbuythepound.com/Coppers-c-356/

Don't use the metallic containing powders, ie. metallic's, candies or pearls

[oldpapps]

Color? I have used powder from PBTP and they have many colors. There are several places on-line that may have the color/s you want.

I'm a cheap scate and wouldn't give up on the black just yet. It can be used to coat tool handles or something.

To night I'm going to the 'big town' and eat with my son before Lodge and will stop at HF to pick up a pound of Red. It is a good price but I have no personnel track record with HF powders.

A few web pages to check:
https://www.powderbuythepound.com/
http://www.eastwood.com/paints/hotcoat- ... ating.html
http://www.prismaticpowders.com/
http://www.allpowderpaints.com/

The only one of these that I have bought from is the top one.

Enjoy,

OSOK

[caliplt]

Cool, coat pre or post gas check installation?

[oldpapps]

I'm no help here.

I'm working on modifying a mold to shorten it and remove the gas check step at the base and half plus of the first drive band just to get away from gas checks and to lighten the finished product. (I don't do subs, I want a faster/flatter shooting pig bullet. Next step could be to hollow point it.)

Load with care,

OSOK