Strange problem encountered with PD'd bullets

[eljefeoz]

if there is titanium dioxide in the powder I can assure you it will sand down a steel barrel.
I use bright white printer paper containing ti dioxide to polish some of my rougher barrels out by fire-lapping with it.

And I had rolled a couple of dozen .284 sized down to .277 145gr RCBS SIL type projjies, with plain white printer paper...last of the white paper PP, better search around for that 16# 'green something' paper

[xyankeeworkshop]

Would Titanium Dioxide be used as a pigment in anything other than a white PC?

[popper]

Sorry R5R, but titanium dioxide is NOT considered an abrasive ( or not a good one). Just above enamel & plastic in mohr hardness. 4-5 won't etch steel (plastics), does clean debris. Coated won't even remove lead from the barrel. TiO2 ~ 6. Now Aluminum oxide is different. The clays used in paper are generally the abrasive. I've gone ~2K 40sw boolits, coated in HF white, put down the barrel of my XDm 40. Also many boxes of WWB, > 1K Xtreme plated, 1K of MBC IDP5, ~1K of recluse/LLA. So I looked at it this morning - NO visible wear. No loss in accuracy or keyholeing and I use a hard alloy, look at the pics of my recovered slugs. I can't really see anything in the pic, kind of fuzzy. Borderguy stated his real problem for the keyholeing - boolits too small. 356 in a 356 bore, he didn't state the alloy, isn't 4.7 unique a mid range load in 9? I did stay away from the HiTek coatings with metallics for this exact reason. No, I'm not saying his metallics will cause wear, just don't know.

[xyankeeworkshop]

Thanks for that, Popper. That perspective has me breathing a little easier since I've completely come over to the new world of PC and burned my ships behind me.

This little controversy does beg other questions: With PC boolits, is it the epoxy/polyester base, the pigment, or the combination of the two that makes it effective? Being a Pigletcoater, I look at that glass jar of acetone on the shelf with a pretty layer of HFPC red settled at the bottom and wonder what would happen if I were to filter the sediment out and "clearcoat" my boolits instead as an experiment.

[fastglock]

All GOOD on my end !! Not a hint of wear

Kimber 45 - 400rds
G35 KKM- 1500 rds
G34 KKM- 600 rds
16" 300BLK SS Stoner- 1000 rds
13.75" 300BLK - 2000rds

All boolits coated with black gloss TGIC . ES or tumble.

[Doc Highwall]

i just thought of something has anybody looked to see if they have any wear on their sizing die after sizing PC bullets besides their gun barrel?

[waksupi]

Glad this thread came up, I asked about the possibilty of barrel wear a few months ago in another thread, and the response I got insinuated I was an idiot for even asking.

Fred

That was the kind of reply I had also received. Maybe I did have reason for concern.

[popper]

Yankee - I think the stuff on the bottom is plastic, clear is solvent. Even with the lacquer thinner. Doc - speed through the Lee sizer is too slow to really cause any wear. I think the TiO2 % in white paint is very low, expect it to be the same in PC, if it is really used - we don't know. Will it wear out a barrel? Will jacketed wear out a barrel in 243 after 10K rounds? Personally, I see no accelerated wear and if mine wear out, I'll just replace them. AR barrels are only a few $100.
No one is an idiot for asking almost anything. Caution is always wise. I have decided not to use the HF black, it is flat black and probably more 'granular'. If they won't trade it for red I only lose $5. Now out to cast another 500 40sw with a softer alloy. Play time again.

[Aunegl]

Would Titanium Dioxide be used as a pigment in anything other than a white PC?

http://en.wikipedia.org/wiki/Titanium_dioxide

[destrux]

i just thought of something has anybody looked to see if they have any wear on their sizing die after sizing PC bullets besides their gun barrel?

No, my Lee push through die has popped out about 600 perfect .401 bullets with no increase in diameter. I did notice the sizing ram has become polished, but I attribute that to it operating unlubricated, not anything to do with the powder coat.

I will say that I powder coated some AR-15 magazines with the HF flat black powder and you can file your fingernails with them, but the anodizing in the mag well of my AR has actually worn the powder coating from usage, so it's softer than anodizing.

I haven't noticed any damage in any of my firearms, but none of them have eclipsed 1000 rounds of it yet and I've only used the red on bullets so far (and now I may never try the black). I wonder if they make clear powder coat? That would sidestep any unnecessary ingredients that could be causing wear.

[NWPilgrim]

Wouldn't throat wear indicate hot gas rather than bullet jacket? It seems if the coating was the abrasive that the entire length of the rifling would show increased wear. If it is just the throat that is worn, would not that indicate gas passing around the bullet (not obturating quickly enough)? What is the hardness of the lead?

[xacex]

I am looking into the MSDS a little more, and found one black TGIC that has quartz in it. That will wear a barrel. http://www.paintdocs.com/webmsds/web...dno=PBS4-C0009 Quarts has a Mohs hardness of 7 which would be considered an abrasive hardness. Not a 9, but close enough.

Several colors have titanium dioxide in them.

It might be wise to look at the MSDS of the different powers we use, and avoid those colors that have titanium dioxide or quatz as ingredients. Candy, and clears?

[Boarderguy83]

The lead im casting is made of used WW's. I am leaving the bases of the rounds clean lead, while PC covers the rest of the bullet. If you all believe that the problem lies in the use of the flat black HF PC, then I will have to burn through the last of the black HF rounds that I have, and get some of the HF red, and see how that does through the pistol with the stock barrel. A new barrel isnt that expensive, and I really love this entrire PC process, so Im going to go about doing what I need to do, to continue PCing my rounds. Thank you all for the replies, and input.

John

[Boarderguy83]

NWPilgrim, please excuse my ignorance, but I am confused as to how the hot gasses would erode the rifling simply by escaping from around the bullet. The hot gasses are what propells the bullet down the bore, so, wouldn't the hot gasses touch all of the rifling on every shot evenly? Just a question from a relative newby.

John

[xyankeeworkshop]

http://www.specialchem4polymers.com/...px?id=abrasion

"The hard truth about the abrasiveness of TiO2...

Titanium dioxide pigments are harder and more abrasive than most other additives used in plastics applications."

And just how abrasive is that, exactly?

OTOH, to keep it in perspective: There are lots of ways to wear a bore.

http://pistol-training.com/archives/8648

I've only used the HF red as well with no problems that I've managed to notice. I need to take a closer look. The unopened jug of HF black I have may just stay in that unopened state. I do know that clear powdercoats are indeed manufactured, so that may just be the next trial.

[xyankeeworkshop]

...but if what Xacex says is true, maybe clear powder with quartz in it isn't such a hot idea.

[oldgeezershooter]

Wouldn't throat wear indicate hot gas rather than bullet jacket? It seems if the coating was the abrasive that the entire length of the rifling would show increased wear. If it is just the throat that is worn, would not that indicate gas passing around the bullet (not obturating quickly enough)? What is the hardness of the lead?

Maybe he is also getting barrel wear. Thus the keyholeing.Might also get the barrel checked for proper hardness.

[TheDoctor]

Wouldn't throat wear indicate hot gas rather than bullet jacket? It seems if the coating was the abrasive that the entire length of the rifling would show increased wear. If it is just the throat that is worn, would not that indicate gas passing around the bullet (not obturating quickly enough)? What is the hardness of the lead?

That was what I was thinking. If the boolit ran out of coating, then severe leading should result in the unworn portion of the barrel, I would think.

[xacex]

Quartz was in the Black P/C of that particular brand that I linked to. The clear shouldn't have any of that in it, and no Ti because it is not an opaque color. That would be my choice right now.

I did manage to get a hold of H/F, and they sent me the MSDS for all of their powders. In the black P/C no Ti is mentioned, but one thing they put on their with no mention of what it is bothers me. They list "matting agent" in there as one of the harmful substances. What ever makes it have a mat finish might be the culprit. Also included are Baryte which is a soft mineral, and Calcite which is also a soft mineral.

All of the other H/F colors have Titanium dioxide, and a pigment called middle chrome? I hope it doesn't have Chromium in it. That is hard stuff 8.5 Mohs.

I don't know how to put PDF's in here so if anyone would like to look over the H/F P/C MSDS for any or all of the colors shoot me a pm, and I can email it out.

[TheDoctor]

NWPilgrim, please excuse my ignorance, but I am confused as to how the hot gasses would erode the rifling simply by escaping from around the bullet. The hot gasses are what propells the bullet down the bore, so, wouldn't the hot gasses touch all of the rifling on every shot evenly? Just a question from a relative newby.

John

IIRC, hot gasses bypassing the bullet will have a serious effect on the throat. They travel MUCH faster than they will propel a boolit. Look at the flame cutting that occurs with some revolvers. And there is the idea that the forcing cone splitting on the Smith 19's shooting light bullets is partially attributed to the severe impact of gas bypass.