The base can cause leading but only if the lead isn't of a proper hardness to begin with, hence why I said leading was possible but not likely.I would think ignition and deflagration would have a more destructive effect on the coating on the base of the bullet than exposure to nitro.
Missing coating from the base won't result in leading, either. The base of the bullet isn't really all that much in contact with the lands or grooves of the bore.
Interesting. Did the method of application - tumble, slurry, roll, etc - or brand and type of powder coat seem to make any difference? Also are we talking about nitrocellulose (single-base powders) or nitroglycerine (double- and triple-base powders)?The base can cause leading but only if the lead isn't of a proper hardness to begin with, hence why I said leading was possible but not likely.
The issue with the nitro content causing degradation of the coating is a real one and has been established to be true, particularly with gunpowders having a nitro content at or close to 40% (Bullseye is one such powder). If the bullets are stored tip down the gunpowder is in contact with the power coat. Over time there is a reaction. Several members here and elsewhere experimented with long term effects of various gunpowder and powder coat and have shared their results here. The coating absolutely softens over about a year. I'm unaware of longer experiments than that.
I don't have links to the threads in question offhand but they can certainly be researched. Bullseye is a double base powder IIRC; in any event it certainly is a fast powder, which tend to have higher nitro content.Interesting. Did the method of application - tumble, slurry, roll, etc - or brand and type of powder coat seem to make any difference? Also are we talking about nitrocellulose (single-base powders) or nitroglycerine (double- and triple-base powders)?
I know the bullet's base obturates during firing (duh! that's what seals it) and that alone ought to disrupt the powder coating and might maybe possibly expose some of the base to the bore but I was thinking it wouldn't result in leading because it's such a confined area and such a small contact surface. Could be wrong. Interesting that some observations have been recorded on this. I hadn't heard about nitro exposure breaking down powder coating before. We use powder coated equipment in medicine quite a lot and I know there's at least some exposure to oxygen and nitrogen that takes place but not nitroglycerine or nitrocellulose. I think the sample freezers that handle liquid nitrogen are powder coated. Not sure, though.
Well, this certainly changes my mind about switching my hard-cast/gas-checked lead or jacketed bullets to powder coated bullets. I use 2400, Blue Dot and Unique for .44 magnum mostly, and all are double-base powders. I did buy some powder-coated bullets from MCB for .357 Magnum but only 500 or so. I will burn them up and not replace them.I don't have links to the threads in question offhand but they can certainly be researched. Bullseye is a double base powder IIRC; in any event it certainly is a fast powder, which tend to have higher nitro content.
The powder coat does not get "disrupted" at any point during firing except for the parts that are contacted by the rifling (see my avatar for a perfect example of this). In fact, if you hit a coated projectile with a hammer, nothing should flake off if the coating is properly bonded to the lead.
Again, unless the bullets are stored long-term there is no softening of the coating. Further, I have bullets which have been sitting nose down for several years now with no adverse issues during firing (I have not however pulled any to check for condition). It doesn't work like paint stripper where it removes the coating, it simply makes it softer than it normally would be.Well, this certainly changes my mind about switching my hard-cast/gas-checked lead or jacketed bullets to powder coated bullets. I use 2400, Blue Dot and Unique for .44 magnum mostly, and all are double-base powders. I did buy some powder-coated bullets from MCB for .357 Magnum but only 500 or so. I will burn them up and not replace them.
Fascinating subject. Thanks for the info and if you come across those links, please post them.
Thanks. I noticed there was an examination of the application method. I will need to read the rest later. Not on an iPhone preferably.This came up with a brief search here:
https://www.thehighroad.org/index.php?threads/bullseye-vs-powder-coat.777918/#post-9876059
There is also this one: https://www.thehighroad.org/index.php?threads/a-partnership-for-powdercoating.753510/
and this one which is a continuation of the one above: https://www.thehighroad.org/index.php?threads/a-partnership-continued.780818/#post-9916240