Coating thickness variation

[10sandxs]

I've been powder coating for several years, pistol calibers only. Also asbb, not spray gun. I tried hi-tek a month or so ago. Process is easier, but it takes just as long to get similar results due to multiple coats.

One advantage I do see in hi tek is the film thickness uniformity. As the bullet seater interacts with the sides of the bullet, the oal is a function of coating thickness. Large variations in thickness will give larger variations in oal. Hi tek is significantly more uniform than powder in my experience.

My 2 cents.

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[Leadmad]

I agree thickness can vary if you don't use the same technique each time you powder coat using tumble method, Not to dismiss the HI-Tek coating but I have been able to Powder coat consistently the same thickness using the same method each time.

I use a clear 3 litre rectangular clip top container and place 6 handfuls of cast bullets in each time regardless of calibre and add 3 of the largest Lee dipper of powder and with the top on rotate the container in 360 degree fashion until all the powder is on the bullets by this time the powder has mostly come off the container walls and then add another 1/2 lee dipper and repeat and look at the bullets and powder on the walls of the container, Im looking for when the powder stops sticking to the bullets and starts to sit on the bottom of the container and the walls of it then I stop adding powder and start cooking, I waste very little powder this way and my coating appears very uniform,

Around my neck of the woods Humidity is always at least 45-85% and have never ever had a problem with powder not sticking year round so Im lucky I guess

Cheers

[Dragonheart]

I've been powder coating for several years, pistol calibers only. Also asbb, not spray gun. I tried hi-tek a month or so ago. Process is easier, but it takes just as long to get similar results due to multiple coats.

One advantage I do see in hi tek is the film thickness uniformity. As the bullet seater interacts with the sides of the bullet, the oal is a function of coating thickness. Large variations in thickness will give larger variations in oal. Hi tek is significantly more uniform than powder in my experience.

My 2 cents.

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There are equipment issues that affect OAL a lot more than the variation of PC. Typically a single coat will be 1-2 thousands, so are you getting larger variations in your coating?

[NyFirefighter357]

I was having trouble getting an even coat of PC with the shaking method but I didn't have the black BB's. After failing with the blue air soft BB's & not wanting to wait for the black ones I decided to try my HF double tumbler. I haven't looked back. It's even & effortless, I can coat about 8lbs in each tub in just a few minutes. I PCed & baked about 100lbs of 38's today.

[10sandxs]

There are equipment issues that affect OAL a lot more than the variation of PC. Typically a single coat will be 1-2 thousands, so are you getting larger variations in your coating?

The last time I measured before sizing, yes, significantly larger than 1-2 thou, more like 2-5. Never gave it much thought till I was checking OAL when working up a new load. I size after coating so thought no big deal because your swaging to the right diameter on the bearing surface.

I was getting large variations in OAL and it was driving me nuts. Even went back to the single stage to diagnose. Coated and uncoated bullets... bingo, we have our "winner". Uncoated seated fine, coated didnt.

The math: assume a 30 degree angle (from vertical) where the seater plug contacts the sides of the bullet. It certainly varies, but as the angle decreases, the affect gets WORSE. Trigonometry tells us that for each 0.001 inch of coating thickness, you'll seat 0.002 inches lower (30-60-90 degree triangle). Now as both sides are coated, you have 2 "thicknesses" added, so the difference is doubled to 0.004" per 0.001" of coating variation.

So, on a 30 degree taper, each 0.001" of variation could result in 0.004" of OAL change. If you have 0.003" of variation, you can get 0.012" of OAL variation which is significantly more that I would expect from reasonable quality reloading equipment.

Coating method i use(d) is vibratory tumbler. Just cast about 1000 rounds so I may give powder another try, just verify.

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[BrutalAB]

Most of my die sets came with two seater stems, one for flat nose boolits and one for roundnose, i do not remember the last time i used the round nose. Provided your boolits are a flat nosed, i would assume this will eliminate your problem. I vaguely remember having similar problems years ago, was quite pleased when i also realized that i can load different boolits to the same o.a.l. without adjusting my dies.

Hope this helps.

[cwlongshot]

I have found much more consistent thickness since I began “sifting” my coated bullets before baking in/on a basket screen. Some powders are difficult to get consistencies other easy. Some powders coat heavier and some lighter. Its just how things seem to be.

Only time its a issue is on bore rider style bullets.

I size last.

CW

[10sandxs]

Most of my die sets came with two seater stems, one for flat nose boolits and one for roundnose, i do not remember the last time i used the round nose. Provided your boolits are a flat nosed, i would assume this will eliminate your problem. I vaguely remember having similar problems years ago, was quite pleased when i also realized that i can load different boolits to the same o.a.l. without adjusting my dies.

Hope this helps.

The issue with the flat nose seater is that the bullet must be placed parrallel to the cartridge to start. If it's off axis even a bit, it will often be seated with a slight cant, which certainly doesn't help accuracy. If you get occasional lead shaving when seating a bullet, this is most often the cause. Once you go to a "side contact" style seating stem, life (accuracy) gets better. Next go to a sliding seating stem like redding competition dies and life is about as good as it can get...

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[cwlongshot]

The issue with the flat nose seater is that the bullet must be placed parrallel to the cartridge to start. If it's off axis even a bit, it will often be seated with a slight cant, which certainly doesn't help accuracy. If you get occasional lead shaving when seating a bullet, this is most often the cause. Once you go to a "side contact" style seating stem, life (accuracy) gets better. Next go to a sliding seating stem like redding competition dies and life is about as good as it can get...

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. Are you using a M-Die?

Unless your using real fat for caliber bullets. The Mdie makes straight seating and consistant neck tension EASY PEASY!

Some hot melt glue can customize the seater stem “pocket” for most bullet
Profiles nicely.

CW

[10sandxs]

. Are you using a M-Die?

Unless your using real fat for caliber bullets. The Mdie makes straight seating and consistant neck tension EASY PEASY!

Some hot melt glue can customize the seater stem “pocket” for most bullet
Profiles nicely.

CW

Yes, at least a version of it. It helps, and does eleminate shaving, but still allows some runout of the bullet with a flat nose seater. The problem with the hot glue trick is that if the bullet you use to mold it isn't "right" your making all others "not right" too. I've been loading for bullseye for going on 20 years. If there's an accuracy trick to getting good bullets, I've tried it

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[cwlongshot]

I have made seaters for special bullets many times. I never had it less than favorable results. But its no different than anything else. Do it correctly and it works.

JB weld is How I did one on my 357 ro seat SSP bullets for the Maximum. I globbed it in, coated everything with release agent and pushed a bullet in for it to set. Removed everything. Chucked it in my drill Press and sanded filed off excess and touched up to my liking... That was thirty years ago... Its been working fine since. Necessity is the mother of invention.

CW

[fredj338]

I think easier to get uniform coating shake & bake vs spray. HT is pretty consistent.

[Spector]

I stand my boolits nose up and l use Smoke’s clear. I experimented using a shop vac from a distance to blow off any excess powder. It seemed to work fine until l got too close with the shop vac. A less powerful machine l believe might work better. An outdoors job for sure. I wanted a thin, but uniform costing. The white on lead make it easier to tell when you have achieved a thin coat as it will begin to look a little grey.

[popper]

I can get MOA @ 200 asbb PC in 308W, never worried about thickness (not a bore rider) but knock off excess before cooking. I pick them out of the bowl with hemos, tap the base on something hard and drop into the modded 45acp ammo tray to align. Tap & drop removes excess PC.

[fcvan]

What he said ^

I have also had excellent results by measuring the amount of powder I put in my container, measured amount of boolits, and (what I think makes a huge difference) I dump the boolits and ASBBs onto a cooking/baking sheet. Then, I roll the boolits side-to-side. THis separates the BBs and ensures the boolits either pick up more powder or sheds the excess. Either way, if you do the same thing each time it is consistent.

I transfer the boolits to the tray using hemostats unless I'm doind Gas Checked boolits. Then I ESPC using one of the blow dryer guns with fender washers affixed to a backing tray. Then I tap the tray so that any excess powder is removed from the boolit. I am thinking of getting a PB mold for 30 cal so I can tumble. Either that or I will seat the GCs, tumble, then size. I don't know, I've got more 30 cal already to load in coffee cans I may never need to cast them again