Strange problem encountered with PD'd bullets

[xacex]

I don't get the connection to fluid dynamic principles such as Bernoulli's with this problem. Gas cutting from poor fit would erode the throat, and not the rest of the barrel due to cooling and the pressure curve. I do not see any fluids involved.

[rsoper]

I don't get the connection to fluid dynamic principles such as Bernoulli's with this problem. Gas cutting from poor fit would erode the throat, and not the rest of the barrel due to cooling and the pressure curve. I do not see any fluids involved.

gases are fluids.

[gds]

As i have stated earlier. We can argue chemical process till the cows come home. A lot of people have been using the flat black. putting a lot of rounds down range in both pistol and rifle. If the flat black powder coating is the culprit, then Why have we not seen more complaints like this. I have used the flat in my 300 blk model 7, as well as my 9.5inch AR, and honestly cannot tell you how many rounds I have fired thru them. my accuracy has not suffered. I shot a box full of the lee 230 that were only measuring .309 after 2 coats. yet no rifling wear. they shot like garbage. but putting in the NOE 247 again with the flat black powder coating gave me 5 shot subsonic 50 yd groups of less then an inch.

Have also used them in 9mm and 45 acp, .308, .45 colt, and a few others that are slipping my mind right now.

And I have no doubt that there are guys not only on here but on other gunboards doing the powder coat process, using the flat black, shooting them faster and shooting a lot more of them then i have, or even the OP and we have but one report, seeming to put the blame on the flat black.

I am sorry but I am skeptical. I don't think the OP is lying about what he has, but I just have a hard time believing that the flat black is the culprit.

But who knows maybe I am totally wrong and there are thousands of ruined guns out there that nobody wants to admit to.

[xacex]

gases are fluids.

I have to fix that exhaust leak in the truck. I'm getting more stupid day after day. Thanks for the reminder.

Ordered a new header to replace the cracked one.

[geargnasher]

Re: Anodized aluminum hardness from page one, anodized coatings will blunt the points on HSS drill bits if that is an indicator of hardness.

Re: Adding hBN to clear PC, or any PC....my interest is VERY piqued, please continue and report...

Re: Linstrum, I learned more from your two posts than I have in the last week of my life, thank you Sir.

Re: Mechanics of colloidal graphite as an extreme-pressure lubricant....I recall reading that moisture is required for the planar slippage to occur properly. NASA research scientists discovered that colloidal graphite functions as an abrasive to steel and titanium in simulated outer-space conditions and pinpointed absence of moisture to be the cause.

Re: Lack of abrasive wear in barrels from aluminum gas checks....there is a high film strength lubricant associated with shooting these, together with lubricant fouling/residue coating of the barrel that also holds residual carbon and graphite from the propellant. Prediction is somewhere on the order of 100 billion rounds through the barrel before barrel wear would be expected to show up in the fourth decimal place.

Re: Wear tester Popper mentioned... if anyone wants a lab analysis from the Southwest Redneck Materials Certification & Research Center, a not-for-profit organization dedicated to the preservation and enjoyment of firearms and currently headquartered in my garage, please pm for address to send samples. Minimum sample quantity for accurate standard deviation is 137. .45 and .38 caliber preferred.

Gear

[Boarderguy83]

Thank you everyone for all of the input into this thread. I have read a lot of responses and really do appreciate the flood of information that has come in. In all honesty the chemical compisition talk that started was very much over my head and I found myself staring at the screen blankly for a min, as I dont really have a firm grasp of anything chemical related. Never the less, I do appreciate all the responses, and I am still working with the PC'd boolits. I have about 500 PC'd flat black rounds that Im still pushing down range, and am making the switch to the HF red to see what effect that may have.

All in all I probably received a defective barrel from lone wolf, but oh well, I can honestly say that I got my use out of it. I put just shy of 10,000 rds through it in various competitions and such. I am now interested in seeing if any noticeable wear will be found in my stock G19 barrel. Time will tell.

Thanks again for all the posts.

John

[ebner glocken]

"Re: Linstrum, I learned more from your two posts than I have in the last week of my life, thank you Sir."

Post #91 needs to be framed. I work in an environment that wear factors are a very real thing. I showed that post to a couple of coworkers and said "have you ever heard this put so well?". It doesn't just apply to guns. Well done sir!

Ebner

[danr]

oddly, i have had this very same wear happen to one of my 45's from shooting brass case jacketed projectiles. i have a couple of other pistols that had about the same amount of use and have not seen the same wear on my other firearms. so i account for it just being a poorly made barrel. my 45 barrel had warn 2 of the rifling grooves to near smooth surface. now mind you i also have only fired brass jacketed home swaged projectiles from my firearms since i purchased them, and i have easily put 10k or more rounds through each of them.

anyways.. thought this info could help you all.

thanks,
dan

[gimling]

I doubt it is the powder coat. I have shot hundreds of PC rounds through my Taurus, powdercoat does not make the bullet any harder, its more of a protective lubrication.

On a side note I noticed that the flat colors don't size like butter like the gloss and I have to clean the barrel more often than when I use a glossy powder coat.