Powder coat sitting on base vs loose in tray

SO I have powder coated 9mm, 30-30 and 30.06 bullets and all the time I just shake and baked on a wire rack in the toaster oven. I was working toward a 6.8 SPC round and cast a bunch, water quench and powder coated and quenched. When Powder coated I tried using the mini ice cube trays I saw people using to get nicer bullets. I measured some bullets out of the mold at .278 but after powder coating I am measuring .285 and that seems very thick for powder coating. Using Eastwood green. They are getting tore up in the .278 sizer when trying to size them and put on gas checks. I mean its pretty rough pushing them through, harder than any I have done before. I saw lead dust in the bottom of the lee sizer tray and open spots on the sides of the bullets. They are coming through.277 and not .278

Could standing them on the base make the coating thicker from running down from the nose to the driving bands? I cast 600 of these and its looking like they are getting melted again, but I don't want to screw this up again. What looks blue is lead. The iPhone camera did that.

Attachment 321495

Well, I have never used case lube sizing before. I threw a bunch of bullets in my zip lock for case sizing and sprayed with case lube. Didn't work for first ten and now they are better. I guess lubes getting through and cleaning the trash out from before. I wouldn't say great, maybe useable.

Thought on doing it better next time?

Attachment 321496

Interesting. I do all my bullets standing up on their bases and have not seen the PC become thicker on the base. However, I'm using a different PC powder (Smoke's clear). I'm cedtain the bases are not getting thicker on mine because I have a couple of bullets that drop a little smaller than I want, so I size first for uniformity then PC without sizing after. I have measured those and they come form the sizer at 0.311 and the bullets, including the bases measure a uniform 0.313 after PC.

I always stand up my bullets for PC. 210gn .308 bullets will measure .310 before coating and .312 after with Smoke's clear. .313 with Eastwood Lt Blue. Same with other molds I've used. Even my 6mm bullets only gain .002 when using Smoke's clear.

IMHO, something is wrong if you are gaining 0.010" with PC.

Agree that something's a bit out of kilter with 7-thou growth from PC.... (but....)

Lose the ice cube tray and stand them up on their own -- see if that affects coating growth on curing.
Are you using a Lee push-through sizer? If the sizer's clean, the PC should slide through slicker than "xxxx"
Worst case, Hornady-1-Shot lube will work too - IF - absolutely required.


Thought: Forget the water quench. Completely. (But especially after the PC)
PC largely obviates the need, and its effects may in fact be part of your problem.

Try independent stand-up -- and no water -- on a dozen or so, and get back to us with the results

my OCD will not allow me to bake boolits laying in a tray or basket, so I set all my boolits on their base. I do use hardware cloth baskets for baking but use cut to fit silicone baking sheets in the baskets.

kinda wondering if the OP's current issue is from too much powder left on the bullets. Is there a chance that your normal method was allowing the excessive powder to be knocked off/loose when put in your baking basket. Maybe try dumping your tumbled boolits into a colander type basket and shake n jiggle enough to knock off the excessive powder, then stand them up using your preferred method.

Way too much powder. That and you water quenched them before sizing from 285 to 277/8. The only thing that will give is the coating.

I use the little ice cube trays for my .30 cal boolits and can say it’s not the tray but possible an excess of powder of the boolit itself. After applying the powder coat shake any excess off so you have less powder adhering to the lead. The powder doesn’t have to go on thick to cover up the lead. Also, you can try polishing your sizing die with some jb bore bright or flitz. Don’t go crazy just polish any possible rough spots

I'm not doing many rifle boolits, but plenty of 38, 357 and 9mm. I have a sheet of aluminum that I keep a sheet of non stick aluminum foil on. Keeps the pc from sticking. But after shaking, I pick up with forceps and tap on the rim of container. Knocks off excess. And yes, you are making it hard by quenching. Zero need to do that when you pc.

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Too much powder on your bullets. I powder coat my bullets using my tumbler and wash out the tumbler with soap and water later. If there seems to be too much powder on the bullet, I pick out the bullets and tap the tweezers against the side of the tumbler and the excess powder falls out. Then, I place the bullets on non-stick aluminum foil. Since I use Hornady One shot on my rifle cases and have carbide pistol dies, I use the old case lube and pad to size lube my bullets later. The bullets swage well and won't bind up in the resizing die. If the painted bullet is still too large, maybe consider sizing the bullets before powder coating and after.

Yes I have seen thicker bases. Powder coat flows. It is supposed to. When you bake lying down your likely getting fat "sides" instead if "bottoms". This is a fault of the AMOUNT of powder your allowing to be on the bullets.
I recomend that you sift off excess powder. This will get you a much better product. You wont be able to effect the look or preformance of your coating you will only improve upon it.

CW

No need to WD before PC, just cook for 1/2 hr at proper temp and then WD. Just tapping may remove some powder but shaking (collander) will remove more. Coating is typically 2 thou larger. I always cook base down.

I (again) strongly recommend not water dropping at all -- either before or after -- when PC'g

I am quite obsessive, I use tongs to leave them all standing on the baking silicone
I put a very light coat of transparent paint on my boolits, that makes the gascheck easier to put in the lee sizing
then I make another light layer so that the gaschek is covered
The more layers I make, the less lubricant enters the lubrication grooves.

Why do you use lube at all? I PC so I do not have to use lube.

I also go a bit overboard. I size the base and apply GC, then under size the nose. Then PC, size nose and base again. I do not water drop.

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Originally Posted by charlie b

Why do you use lube at all? I PC so I do not have to use lube.

I also go a bit overboard. I size the base and apply GC, then under size the nose. Then PC, size nose and base again. I do not water drop.

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I have obtained better SD (very slightly uneven speeds) than without using lubricant, it is seen that the sealing created by the lubricant improves the speeds. Shooting at long distance and a large SD is a guarantee of missing the target.

I size my bullets both before and after PC. That way I don't have to worry about trying to size down bullets that have gotten way too big. I also swirl lube my PC'd bullets with 45-45-10 because even a tiny amount of lube makes them more accurate.

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Originally Posted by nueces5

I have obtained better SD (very slightly uneven speeds) than without using lubricant, it is seen that the sealing created by the lubricant improves the speeds. Shooting at long distance and a large SD is a guarantee of missing the target.

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Interesting. I've not had a problem hitting smaller targets at 500yd. SD's are usually 10-12fps. ES 20-40 depending on bullet and load.

I use a very thin coat of tumble lube on some powder coated bullets. I have experienced plain PC bullets that seated with extreme amounts of force on clean brass. MUCH more friction than a normal lead bullet or a jacketed bullet. It can stick to brass like glue when they are both smooth. If I have super shiny brass I give the bullets a very dilute coat of tumble lube.

On clean brass the noses get deformed, the brass stretches unevenly around the circumference of the bullet giving a bullet that is seated straight up and down, but off center in the case because the brass stretched at the weakest point. ALL of my 9mm get either a lightly lubed bullet or if I want it to be really pretty, they get a very thin (20:1 diluted with mineral spirits) coating of LLA on a q tip on the inside case mouths for about 1/8". And I shoot normal sized bullets in my modern 9mms - .356 - .3565 depending on alloy through my .356 sizer.

I have also seen soft lead PC that obturates outwards so hard that it grinds the PC off as it goes down the barrel, and recovered bullets show much bare lead but no evidence of skidding or gas cutting. Slightly harder lead has nice recovered bullets. A thin coat of tumble lube lets the soft bullets get out of the barrel with their PC intact then the barrel stays cleaner and the load shoots much more accurately. I have seen this with soft lead that get above about 1800 fps. All of my high speed lead shooting has been through 30" twist barrrels, so no problems with skidding when I poke around the 2200 fps range.

My powder coating process gives me about .002 thickness. If I had a way undersized mold and gave them a double coat you might be able to shoot the soft bullets faster, but as for now I have seen a ceiling around 1800 fps for slick sided bullets and about 2100 fps for lube groove bullets with PC. Above those speeds they need some lube too. I think the lube grooves act like a shotgun cushion wad and cushion the obturation during the peak pressure/peak acceleration. A slick sided bullet at peak pressure and peak acceleration wants to grow in diameter and it grinds its PC off.

I usually do not clean cases, just neck size. The carbon in the necks acts like a 'lube' when seating PC bullets.

If I do clean the brass then I brush some dry graphite in the necks. I do the same for jacketed bullets.

I've gone up to 2400fps with PC bullets (and gas checks). I've had accurate loads at 2300fps before the 10" rifling twist hurts the accuracy. PC is still intact on the recovered bullets. I've not seen evidence of issues with PC without lube in the barrel. I use Lyman #2 air cooled (~16bhn).

Charlie I start seeing the obturation problems and PC loss only with 8-9 BHN alloys at 2100 fps for lube groove bullets and 1800 for smooth sided bullets in the 30" twist. 1-1-98 alloy. 98% lead. You are shooting 90% lead. Your alloy is so hard compared to what I was talking about. I am nowhere near the rpm threshold, therefore I can shoot butter soft lead at high speeds compared to small bore guys.

At 35k PSI I can't even get the lube grooves to deform with 5-5-90, let alone the stronger driving bands. This is why the PC stays intact - the outward obturation forces are very low with the hard alloy and low pressures involved with shooting a big 30 cal case at only 2300 fps. You need your bullet hardness to bite the riflings and resist skidding at the high RPMs and you don't need bullet hardness to counter obturation forces AKA lube groove collapse.

My 1-1-98 alloy at 2100 fps, recovered down range where it slowed below expansion speeds and loaded to just before the obturation abrasion point of the PC shows the lube groove has just about obturated away to nothing and the lead from the inside lube groove shank is starting to engrave the riflings. The only hint of the lube groove is that the PC there is much cleaner and less blackened from the carbon fouling in the barrel. If you load it any higher than that amount of obturation/ lube groove collapse the base driving band will be naked of powder coat and the barrel will get immense whitish PC fouling.

The 1-1-98 lube-groove bullet at 2100 fps shows the base is forming a pretty decent cupped hollow base from the pressure and the friction dragging the driving bands backwards. the 1-1-98 slick sided bullet shows the hollow base at 1800 fps, right where the accuracy starts dropping off. I imagine that up to a certain point of pressure the bullet engraves and scoots out the barrel. As you keep upping the pressure, the bullet forms a shallow hollow base from the pressure, and the friction pressure at the base of the bullet goes up exponentially. Increase pressure 5% and suddenly with the hollow base formation on the bullet, friction goes up 10% and your PC abrades away, just like it would if you jammed the bullet between your tire tread and slammed the brakes and skidded it along asphalt with a ton of weight on it. The obturation forces can literally measure in thousands of pounds when you are talking about 35k PSI chamber pressures.

Imagine on the slick sided bullet when the pressure forms the flat base into a hollow base how hard the lead is getting squished outwards and its only path of flow is lengthening the bearing surface. If you cut off the barrel at the 1" mark of a 35k PSI 9mm luger while shooting soft lead you would find the base on the recovered bullet mushroomed out to around .40 caliber as it exited the muzzle. Do the same test with a hard bullet and the base would hardly deform. The same thing can be shown on a bottleneck rifle with a jacketed bullet - if you cut the barrel at the point of peak pressure, the bullet base will mushroom when it exits the crown. On the lube-groove bullet mold the obturation forces on the base band are transferred directly to the smallest diameter of the lube groove, and once the lube groove shank diameter grows enough, or meets enough hydraulic resistance from lube, then the base will finally start to form the hollow base shape.

If the lube groove is empty (or mostly empty with a thin skim of tumble lube) it keeps the base nice and flat up to some certain pressure level then suddenly the lube groove bottoms out into the riflings and the bullet's only direction it can obturate is to form a hollow base and lengthen bearing surface(which is one reason why PC bullets can outshoot lubed bullets at higher velocities and softer lead - the naked lube groove that slowly collapses under pressure, the other reason being the hydraulic pressure of the lube in the rapidly shrinking lube groove acts as a sizing die between the bullet and bore, making the bullet undersized and allowing lube to blow past the bullet, which leaves a naked undersized bullet for the last few inches of barrel travel).

If you go only a little bit harder than 8 BHN - 35k PSI - 2100 fps - the obturation abrasion stops, or a little lube on the 8-9 BHN and the obturation abrasion stops.

I can understand your issues with soft lead. I use it for slugs in my muzzle loader for the same reason, obturation.

You are also using a very slow twist rate at moderate velocities so I can understand why you developed your methods.

I am stuck with a faster twist and am limited in my upper velocity due to spin factors, nothing to do with lube. I still have not seen a reason to use lube with PC. FWIW, bullets i have recovered show almost no change in the grooves. They are still just as deep as before they were fired.

If I am going to use lube I don't use PC, just run them through the lubesizer. I do that with a few bullet designs I have.

When powder coating including the base, a GC is unnecessary, so why bother? You are mixing two things, lead bullets w lube VS powder coated bullets. The two are very different.
With the shake and bake, use plain base bullets, in a wide mouth jar. Remove bullets with heated and bent long nose needle nose pliers like so (). Set bose down in a rack, bake in preheated 400 gegree oven for 20 minutes, let air cool in the oven. Use a lube/sizer with case lube only to size to the actual groove diameter.
With my bullets cast hard, I get 2,500 fps and sub 1/2" groups out of my 358 and 350 RM hund in ARs and bolt guns. I also double coat my plain base bullets, so you have a problem with process. Is your powder stored in an air tight container? The powder will absorb water from humidity, if not properly stored, makes for some messed up coatings.

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Originally Posted by charlie b

Interesting. I've not had a problem hitting smaller targets at 500yd. SD's are usually 10-12fps. ES 20-40 depending on bullet and load.

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very good reload, almost always someone escapes and gives me 50 fps more, and ruins my group
I get about 1 and 1/2 MOA consistently

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Originally Posted by nueces5

very good reload, almost always someone escapes and gives me 50 fps more, and ruins my group
I get about 1 and 1/2 MOA consistently

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Thanks, I get about the same. Fliers are a pain :) Usually I am the one that ruins the group :)