Powdercoating removed by rifling (leading)

[Alexander94]

Hi,

I have a problem with the pc being stripped off by the lands in the rifling.
In the attached pictures the bullet on the left is sized to .357, the one in the middle is pounded through the barrel and the right one is shot into water.

I have tried the shake n bake method but couldn´t get the powder to stick at all. So i use an es gun to apply the powder with the bullets standing on a tray. (pictures)
400degrees for 20 minutes, passes the hammer test with absolutely no flaking.
accuracy is good (group in the picture is from 28 yards)
The leading only occurs on the lands in the rifling.

0.357 is the largest i can get away with without broatching the throat.

I was really happy with how to loads peformed untill i realised the pc was being removed.
In the beginning i had a problem with the bullets being swaged down by the case, i made a new longer expander plug and the problems were gone.
I dont think there´s a sizing isssue since the pc is only removed where the lands contact the bullet.

Any tips on how i can solve this problem is welcomed.
// thanks

Info:
gun - cz85combat 9mm.
barrel dimensions - slugged to .356
lead alloy - 50/50 ww/pure lead and 2% tin/pewter measured hardness of around 10bhn
bullet - lee 120tc 6 cavity sized to 0.357 after pc. drops at 0.3578 from mold.
powder - vihtavuori n330 at 4grains.
velocity - 1010fps
OAL - 1,051

[dkonrai]

Is the base coated? That might be the issue?
I've shot alot of pc boolits. I get streaks in my Glock due to the rifling but not much just slight.
I run 358 and no leading in a 686.

Sent from my A7 Pro using Tapatalk

[JM7.7x58]

Sharp throat? Or almost no throat?

[Alexander94]

The barrel is a stock cz with minimal throat.
Max oal is 1,065. It seems that the bullet contact the taper in the throat before actually touching the rifling.

[Alexander94]

Is the base coated? That might be the issue?
I've shot alot of pc boolits. I get streaks in my Glock due to the rifling but not much just slight.
I run 358 and no leading in a 686.

Sent from my A7 Pro using Tapatalk
Since i use the stand up method and es gun the base remains uncoated.

[Conditor22]

The base does not need to be coated.
How long and how hot did you bake them (200 C?)
Did you try smashing one to see if the powder stayed on?
Did you shoot both the second and third boolit?

[Alexander94]

The base does not need to be coated.
How long and how hot did you bake them (200 C?)
Did you try smashing one to see if the powder stayed on?
Did you shoot both the second and third boolit?

200celcius for 20 minutes. As mentioned in the post they pass the hammer test, even after pounding the bullet sqaure from all 4 sides the pc is intact. The second bullet is pounded thrue the barrel using a brass rod to check for pc wearing off.

[Petander]

The second bullet is pounded thrue the barrel using a brass rod to check for pc wearing off.

In that case,doesn't that look a bit undersize?

[Alexander94]

In that case,doesn't that look a bit undersize?

Hard to tell from the picture. measures 0,357 after sizing. Largest measurment of the bullet after being driven through the barrel is 0,356.
So it shouldn't be undersize.

[Conditor22]

Welcome to cast boolits Alexander94, I saw you were from Sweden but didn't notice your post count.

if you can't go larger, go harder. Maybe quench after Powdercoating with those boolits (put some of those boolits back in the oven and bake for 30 min at 200C then drop them in cold water right out of the oven.

Is that 200° for 20 minutes in a preheated oven

[Alexander94]

Welcome to cast boolits Alexander94, I saw you were from Sweden but didn't notice your post count.

if you can't go larger, go harder. Maybe quench after Powdercoating with those boolits (put some of those boolits back in the oven and bake for 30 min at 200C then drop them in cold water right out of the oven.

Is that 200° for 20 minutes in a preheated oven

Thank you, i wanted to get away with the softer alloy since i have alot of pure lead. And almost all wheel weights here are zink. So a 50/50 reduces my ww amount greatly.
Forgot to mention that i water drop the hole pan directly after oven. If i let them aircool i lose 1-2bhn. Yes preheated.

[Conditor22]

If you can't go harder, you will need to either go slower or try to go bigger or get a 9mm mold with a gas check.

Can you get linotype there? it's a great hardener.

[Alexander94]

If you can't go harder, you will need to either go slower or try to go bigger or get a 9mm mold with a gas check.

Can you get linotype there? it's a great hardener.

Hmm, one of the main reasons for casting my own bullets is the price, will be using them for ipsc practice and competition, minimum powerfactor for minor is 125. So i need to push them to 1050fps minimum. Maybe it's not possible with as soft alloy. Linotype is not so common anymore. The EU is on the way to to ban lead from everything here.. including hunting ammunition.

[Conditor22]

Last resort, several people have had success casting zinc bullets if you use a steel mold

Cast Zinc Bullets (223) Loading, Shooting, Capturing!!
https://www.youtube.com/watch?v=xJJ4dP2kfnU&ab_channel=elvisammo

[Idz]

I use range scrap (bhn~9) and had leading problems with 9mm Lee 356-125-2R PC with HF red. What solved my problems was 1) PC twice (easy if you use the basket method) 2) size to 0.357 after PC 3) expand case mouth with a homemade M-die punch that is 0.359 diameter which yields a 0.357-0.358 case mouth ID after springback. My punch is inserted into the case about 0.15" deep so bullet drops into case below lube groove. 4) use seating die only for seating and use a Lee FCD for crimping case. My cartridges fail a case guage but chamber beautifully. I think the soft alloys get crushed too much if used 'properly' and the bullet would cock slightly and scrape off PC unless dropped deep into the case.

[Doughty]

Alexander94,
A few questions:
Are you getting lead deposits on the lands in your barrel?
Have you measured the BORE diameter of your barrel?
Have you / do you shoot jacketed bullets in your barrel?
Approximately how many total rounds through your barrel?
Do you have any possibility of using a borescope to examine your barrel?

[redhawk0]

One thing you haven't mentioned....are you getting leading in your barrel? If not...there might not be anything to worry about.

redhawk

[Loudy13]

if you can not get the powder to stick at all trying to shake them I believe that is one issue I have not had any bullets ever that wouldn't take a coating using shake and bake. Maybe you have some contamination somewhere in your process that is adding an oily substance to your cast boolits. Do you water drop when you cast? I had not cleaned my bucket that I was quenching with for a few sessions and I had a batch of bullets that would not hold the pc. They would coat and pass the hammer test and size just fine but then I would be able to scratch the coating off with my fingers. And they did cause leading. It was very confusing since I was doing the exact same thing I always had done. I wash my quench bucket now with dishsoap and hot water before each session and have not had the issue again. Just my 2 cents from a lesson learned.

[Alexander94]

One thing you haven't mentioned....are you getting leading in your barrel? If not...there might not be anything to worry about.

redhawk

Yes im getting a small amount of leading, but only on the lands.

[Alexander94]

Alexander94,
A few questions:
Are you getting lead deposits on the lands in your barrel?
Have you measured the BORE diameter of your barrel?
Have you / do you shoot jacketed bullets in your barrel?
Approximately how many total rounds through your barrel?
Do you have any possibility of using a borescope to examine your barrel?

Yes only on the lands, if you look at the bullet to the right in the pictures you can see that the PC is completely removed from were the lands engage. Bore diameter is 0,348.
Yes i shoot jacketed, a guess would be around 8k through the barrel. Unfortunately i don't have acces to a scope..

[Alexander94]

if you can not get the powder to stick at all trying to shake them I believe that is one issue I have not had any bullets ever that wouldn't take a coating using shake and bake. Maybe you have some contamination somewhere in your process that is adding an oily substance to your cast boolits. Do you water drop when you cast? I had not cleaned my bucket that I was quenching with for a few sessions and I had a batch of bullets that would not hold the pc. They would coat and pass the hammer test and size just fine but then I would be able to scratch the coating off with my fingers. And they did cause leading. It was very confusing since I was doing the exact same thing I always had done. I wash my quench bucket now with dishsoap and hot water before each session and have not had the issue again. Just my 2 cents from a lesson learned.

Here in sweden we don't have the same powders u guys use. The powders available are all TGIC free. Can this be the problem ? With the es gun they adhere good. I tried all kinds of containers and using plastic bbs and so on. I drop the bullets from the mold on a clean towel and never touch them with bare hands.

[Alexander94]

A question, if bullet size was the problem (too small) cuasing gas cutting which in turn removes the PC. Shouldn't the PC be removed where the grooves contact the bullet ? And not the lands.

[redhawk0]

Please correct me if I'm wrong...but looking at your boolit picture...the PC is removed from the Groove. I may not be seeing it correctly...let us know.

redhawk

272803

[Alexander94]

The picture is not the best, the PC is removed from were the lands in the rifling contacts the barrel. Here' a better picture.

[redhawk0]

OK...thanx for the better picture. I think its your powder causing the issue. Have you tried any other powders? Just because it passes a smash test...doesn't mean it isn't abrasion resistant. I think its being abraded off.

redhawk

[Alexander94]

Forgot to mention one very important detail..
When i purchased the gun it was is used condition. Looked like new except for the barrel. It was pitted, it still shot very tight groups with jacketed ammo. sub 2" at 27 yard so it didn't bother me. Is this the cause? I might need to buy me a new gun 😁

[Dan Cash]

You are loosing significant coating on the lands and completely in the grooves from the looks of your pictured bullet.

I stand corrected after viewing your later picture. Your bore looks acceptable for most purposes. Try a soft lube and a not too hard bullet BNH 8 or 9.

[JM7.7x58]

Here in sweden we don't have the same powders u guys use. The powders available are all TGIC free. Can this be the problem ? With the es gun they adhere good. I tried all kinds of containers and using plastic bbs and so on. I drop the bullets from the mold on a clean towel and never touch them with bare hands.

I only have experience with powders containing TGIC. A lot of experimenting has gone on over the last decade. I got to the party late and tried to follow the advice of those having good results. From what I have read the current wisdom is that TGIC powder is the best type of powder for bullet coating. But, TGIC is nasty stuff when viewed from a toxicity standpoint. I assume that is why it is unavailable to you in Sweden.

Your Choice of powders, in conjunction with a harsh throat may be your problem. There are differing opinions on the epoxy based PC. While I have never used them I have read numerous reports of people having problems with epoxy PC adhesion.

JM

[Petander]

Tjenare,

could it be the powder not bonding? Can you scratch it off with fingernail?

I started with Smoke's powders to avoid unnecessary quesswork. A friend sent some from Slovenia.

Here in Finland vendors don't know crap about the powders they are selling. Ask about TGIC ... "huh?"

I know even less but apparently the majority of powders here are epoxy/polyester combinations. Like a shot in the dark,I have some italian powder coming but my main powders are on their way, coming from Smoke. Tested and working.

I started with Hi Tek a couple of years ago and still do it. It was easy. Clear instructions and measuring, times,temps, repeatability and minimum variations possible. Only one powder maker. PC is more random but I'm impressed by the bonding and toughness of some now. And PC is quick for a little batch whenever you feel like casting and coating a couple of boxes. Hi Tek I do circulating 3x10 lbs trays at once,usually.

----------

Back to the OP:s topic, it may be the powder itself not bonding.

Smoke's Carolina Blue here.

https://i.postimg.cc/3J9Pbx2j/IMG-20201206-210141-667.jpg

[tomme boy]

Lap the barrel. Either shoot some bullets with lapping powder on them or pour a lead lap and use the lapping powder on it to remove any defects. I would do the fire lapping route. That way you do not make the muzzle larger. I had to do this on a cz75 that had a bad throat. Once done it really shot well and no more leading.

[popper]

Your coating looks thin. Should increase dia by ~2 thous. It does abrade off. Only cast I recovered looked worse, accuracy was fine - 40sw.
What I find interesting is the raised and wiped alloy in the already cut groove.

[Petander]

Lots of possibilities. Alloy contaminants can do anything,too.

Would you like to try Hi Tek? I have plenty, I can send you some. It is NOT PC but it's a tried and true working coating.

Maybe order PC powder from Smoke and play around with Hi Tek while waiting?

[Forrest r]

IMHO:

I'm going to say it's borderline under cure. Don't know where or how you cook your pc'd bullets. I do mine outside in a shed with the door cracked open. When the wind gusts or comes in at just the right angle it drops the oven temp fast.

I understand people have pc'd bullets with success at low temps (video on line???). I can only assume that their temps were constant and mine were +/- 40* in 15 minutes.

I never had any issues with a charter arms bulldog and pc'd bullets. I've shot this bullet/load combo in it in the past without issues. I cast up a small batch of them (+/- 100), pc'd them and then put a hp in them using forester hp tool. Had 2/1000th's+ pc coating on them that had a glossy shine to them as they should.
https://i.imgur.com/FTFbMo6.jpg

That bullet was recovered from a bundle of wetpack (12" thick bundle of newspapers soaked in water overnight). The nose of the bullet still had the pc coating on it, hence passed the smash test. The body of the bullet was stripped clean. A side view of that same recovered bullet.
https://i.imgur.com/Swqedh0.jpg

In a 3 year period I've had the same thing happen several times. I made a pid to control the heat better and started cooking the batches of pc'd bullets for 20 minutes instead of 15 minutes. I haven't had the problem since.

Don't know if this is what happed to you but it will give you something else to look at.

[Alexander94]

IMHO:

I'm going to say it's borderline under cure. Don't know where or how you cook your pc'd bullets. I do mine outside in a shed with the door cracked open. When the wind gusts or comes in at just the right angle it drops the oven temp fast.

I understand people have pc'd bullets with success at low temps (video on line???). I can only assume that their temps were constant and mine were +/- 40* in 15 minutes.

I never had any issues with a charter arms bulldog and pc'd bullets. I've shot this bullet/load combo in it in the past without issues. I cast up a small batch of them (+/- 100), pc'd them and then put a hp in them using forester hp tool. Had 2/1000th's+ pc coating on them that had a glossy shine to them as they should.
https://i.imgur.com/FTFbMo6.jpg

That bullet was recovered from a bundle of wetpack (12" thick bundle of newspapers soaked in water overnight). The nose of the bullet still had the pc coating on it, hence passed the smash test. The body of the bullet was stripped clean. A side view of that same recovered bullet.
https://i.imgur.com/Swqedh0.jpg

In a 3 year period I've had the same thing happen several times. I made a pid to control the heat better and started cooking the batches of pc'd bullets for 20 minutes instead of 15 minutes. I haven't had the problem since.

Don't know if this is what happed to you but it will give you something else to look at.

Seems like you had similiar problems. Tomorrow i will experiment with the temperature and curing times. The powder manufacturer say's 200 degrees celcius for minumum of 8 minutues and 16 max after part metal temeperature is reached.

[Alexander94]

Lots of possibilities. Alloy contaminants can do anything,too.

Would you like to try Hi Tek? I have plenty, I can send you some. It is NOT PC but it's a tried and true working coating.

Maybe order PC powder from Smoke and play around with Hi Tek while waiting?

Thank you, but first i think i will experiment with the PC some more. Do you know where i can buy smokes powder and get it shipped to sweden ?

[Alexander94]

Your coating looks thin. Should increase dia by ~2 thous. It does abrade off. Only cast I recovered looked worse, accuracy was fine - 40sw.
What I find interesting is the raised and wiped alloy in the already cut groove.

I measured the coating and it adds just around 0,002 in. I examined the bullet closer and like you mentioned it looks like the rifling has slipped some before engaging. I will try a reduced load tomorrow and se if it helps.

[Conditor22]

Forgot to mention one very important detail..
When i purchased the gun it was is used condition. Looked like new except for the barrel. It was pitted, it still shot very tight groups with jacketed ammo. sub 2" at 27 yard so it didn't bother me. Is this the cause? I might need to buy me a new gun ��


Lookat buying a new barrel before you buy a new gun IF you decide to go that way.

[mvozz]

I was having the same problem with leading. I have been shooting PC Boolits for over a year with no problems until I coated some for a 380. By the end of a 7 round mag I was totally leaded up. I pulled a few boolits and the coating looked terrible on the side of the boolit. After pondering a bit I determined that the coating wasn't cooked enough. 20 more minutes in the oven and the problem went away. I realized that I had over 300 boolits on the pan and I believe they just didn't come up to temp for long enough. I didn't check the temps but I do know the problem was solved after a second cooking. Just my experience.

[slide]

Alexander94, here's another option for measuring your temp. Go to amazon and order a digital thermometer with a thermocouple. Drill a hole in a coated bullet and insert thermocouple and squeeze bullet down on the thermocouple till it is secure. Lay your t-bullet in with your coated when you bake.The thermocouple will not interfere with the oven door closing. This way you will know when you reach pmt and can start a timer. Everybody does it different but I like knowing that my coating is cured right. I am shooting cast in a 223 and it does make a difference in accuracy. Pistol rounds not so much.

[charlie b]

First, the picture of the bore it looks dirty, powder deposits, maybe leading. After it is scrubbed until you can see bare metal, then think about lapping it.

Second, the loss of PC may be from the beginning of the rifling. Not sure how old the gun is but many mfgs these days do not 'ramp' the rifling, it is sharp edged and will 'scrape' off PC like that. That's why people like Doug can make money doing throat jobs on pistols.

Third, if the barrel isn't leading just keep shooting. If it is leading then try what some have already suggested. Maybe some softer lead, thicker PC coat, different cure, etc.

Last, no it isn't normal. I shoot cast bullets in my .308 rifle at 2000fps and higher and the coating is still in the grooves. This is with a factory barrel that you can see the chatter marks from the machining process, even after 3000 rounds.

[Petander]

Thank you, but first i think i will experiment with the PC some more. Do you know where i can buy smokes powder and get it shipped to sweden ?

Smoke is a member here.

Look under "Vendor sponsors" , he has a shop page down there.

[Gamsek]

Smoke is a member here.

Look under "Vendor sponsors" , he has a shop page down there.

https://uploads.tapatalk-cdn.com/20201209/e348ac612136ddaeacc5d1a552feb202.jpg

Smoke. Excellent!
You will pay some shipping 35€, some local custom fees, but it is worth. My favourite are (not because of colour, but because they stick like crazy and smooth)
CarolinaBlue
YellowGreen
TrafficPurple
FlameRed (new for me in 2020)
Clear
Chrome
https://uploads.tapatalk-cdn.com/20201209/7c401b7f1cca3c3579b7990be5bf87c3.jpg
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https://uploads.tapatalk-cdn.com/20201209/77e11a6ea8d2bc0305bf5fb55ed1cce7.jpg

[Alexander94]

Alexander94, here's another option for measuring your temp. Go to amazon and order a digital thermometer with a thermocouple. Drill a hole in a coated bullet and insert thermocouple and squeeze bullet down on the thermocouple till it is secure. Lay your t-bullet in with your coated when you bake.The thermocouple will not interfere with the oven door closing. This way you will know when you reach pmt and can start a timer. Everybody does it different but I like knowing that my coating is cured right. I am shooting cast in a 223 and it does make a difference in accuracy. Pistol rounds not so much.

I will do this today, i have thermocouples from my pid build so i will use these.

[Alexander94]

First, the picture of the bore it looks dirty, powder deposits, maybe leading. After it is scrubbed until you can see bare metal, then think about lapping it.

Second, the loss of PC may be from the beginning of the rifling. Not sure how old the gun is but many mfgs these days do not 'ramp' the rifling, it is sharp edged and will 'scrape' off PC like that. That's why people like Doug can make money doing throat jobs on pistols.

Third, if the barrel isn't leading just keep shooting. If it is leading then try what some have already suggested. Maybe some softer lead, thicker PC coat, different cure, etc.

Last, no it isn't normal. I shoot cast bullets in my .308 rifle at 2000fps and higher and the coating is still in the grooves. This is with a factory barrel that you can see the chatter marks from the machining process, even after 3000 rounds.

Hi, the barrel is 100% clean to bare metal in the picrure.. i also firt thought it was lead/powder so i ordered some copper mesh balls (chore boy ? ) and scrubbed the barrel. All the holes and pitts visible is eroded down into the metal.. and yes it leads after just 1 round. The rifling is taperd down into the throat so not a sharp edge. I will try some thicker coats and experiment with cure time. Thank you

[Petander]

Hi, the barrel is 100% clean to bare metal in the picrure..

https://i.postimg.cc/wvyh4bjC/Screenshot-20201207-203816-Gallery-2.jpg

Here is your scraping problem.

What on earth has happened to that barrel?

[Alexander94]

https://i.postimg.cc/wvyh4bjC/Screenshot-20201207-203816-Gallery-2.jpg

Here is your scraping problem.

What on earth has happened to that barrel?

Good question.. i guess the owner before me wasn't a big fan of gun maintance.. unfortnunately a new barrel is about the same price as i paid for the gun. Haven't decided if to buy a new gun or a barrel.

[charlie b]

That looks like deposits on the lands, not pits, which is why I suggested a good cleaning.

[John in WYO]

200 degrees Celsius is 392 degrees Fahrenheit.
I don’t powder coat but is his temp too high?
Ignore my post if it was already addressed.
Thanks.

[redhawk0]

200 degrees Celsius is 392 degrees Fahrenheit.
I don’t powder coat but is his temp too high?
Ignore my post if it was already addressed.
Thanks.

No...I bake for 26 min @ 400*F. The extra 6 min is to warm up the boolits.

redhawk

[popper]

Looking at the pic of coated/slugged//shot. slugging bullet sized or not? It has tails on the drive bands - that come off when fired. The shot one has balls on the base. Screenshot pic on front band shiny spot in groove/ non-shiny also in groove. I assume shiny is taller than non-shiny and I don't know how that is possible. Not surprised by the lack of PC on the fired one (first pic) The 40sw I recovered was green to start and recovered was a powdery white.
There are several grades of PC, some are architectural grade with no abrasion resistance, some are machinery grade. Smoke's is machinery grade.

[bayjoe]

Are you letting the bullets cure?

[Dimner]

If you do end up going with smoke's powders (which I highly recommend), Carolina Blue, Signal Blue, John Deere Green, Wine Red and Traffic Purple have all coated the easiest for me with the shake and bake method. Very full and consistent coating. Carolina blue, and John Deere green being the absolute easiest.

I have found it a little harder to get the pigment to fully coat with Bacon Grease, Translucent Copper, and Jet Black. These colors have always fully coated, but some areas had pigment missing. There was still polymer or what ever PC is over the entire bullet.

Just trying to save you some trouble since you will probably want to get it right in your first shipment.

I'd also suggest getting a bag or 2 of the airsoft bb's that hatch sells. Are you able to source the proper plastic containers for shake and bake?

[Win94ae]

That looks like deposits on the lands, not pits, which is why I suggested a good cleaning.

Exactly!
This is pitting.
272961
And it doesn't lead foul at all.

[Boogieman]

i had the same problem with my Wife's 9mm Ruger LC9s. Coating twice and sizing to .358" solved it for me. I would try baking longer at 400F.