Another reason to powder coat

[gloob]

So, when you say you know some folks who shoot thousands of cast rounds w/o cleaning their barrels and without smoke, well, inquiring minds (at least this one) want to know: how are they doing it?

I have a pretty solid working theory, at this point.

First, let me say there are many good reasons to powder coat. Excessive smoke is a valid reason, and there are some firearms which smoke cannot be avoided any other way than powder coat. All revolvers will fall into this group, IME. But in most (not all) closed breech handgun and bullet combinations, I find that smoke can be so significantly reduced as to be imperceptible, simply by filling the bore completely and quickly. If you can take it for a fact that I am not exaggerating, I'll spare you my testimonials of smoke-free indoor shooting, and I will demonstrate the current exception that does smoke and what I think I may have learned from it.

Glock 20, shooting 10mm reloaded in 40 SW cases.
When I started reloading for this gun, I had already sorted out my 40S&W handgun cast loading. So I was not surprised when I successfully loaded for this gun without fouling. I WAS surprised by the smoke. This is the first time I have ever had significant smoke in a semiauto where I had absolutely no fouling. It seems to come from the back of the gun, like the chamber is smoking!

Looking at this in hindsight, there are two mains reasons here that this combination is allowing unusual amounts of gas blowby.

1. 40 SW case barely covers the lube groove on my MBC bullets, even at slightly shorter than regular 10mm OAL. The entire lube groove is exposed before the bullet even plugs get to the lead, let alone plug the rifling.

2. The case mouth does not seal in the chamber, anyway. Chambers are generally cut tighter at the case mouth and looser everywhere else. Especially in Glocks. When you're using a short case, the case mouth ends at the middle of the chamber where it's cut loose. At soon as the powder ignites, the case mouth has more room to blows out to fill the chamber, allowing space for gas to blow around the bullet. I know this is in fact the case in this gun, because my 40SW glock needs a firm taper crimp to even chamber a round, and I can't use some of my thicker cases. I save those for my G20, which I don't need to crimp my 10mm/40 combo to chamber.

Out of 10mm cases, no smoke.

Well, that explains how to MAKE smoke. Assuming your gun and bullet combo can seal the bore, effectively, why do so many people still have smoke? If you have smoke, it's because you are not sealing your bore. And I don't care if one has slugged your bore and sized their bullets accordingly. For one, the biggest reason your bullets are still undersized and you don't know it is because of case swaging. The black powder guys seem to be the only ones that know how to expand a case for a lead bullet. And secondly, if you want the lowest smoke, you don't size the bullet for the bore, you size it to fill the chamber. I have never slugged a bore, yet.

I'll spell it out. 1. Bullet > bore. 2. Bullet not significantly < chamber/throat. 3. Expander = diameter of bullet. If that sounds too easy, it's not. Because hardly anyone goes out of their way to try it, and even custom expander manufacturers don't offer it right, except the black powder guys. Take care of rule 1, and rule 2 almost always follows, unless your chamber is cut weird. And conversely, taking care of rule 2 generally satisfies rule 1. It's the third step that seems to be bordering on lost knowledge. There was probably a time when every other person who owned a gun knew this.

Even if you still prefer to pc, I suggest you try the proper size expander for your bullets. You may get better accuracy and even less fouling (if you get any fouling, at all, with PC).

[Dragonheart]

I think the answer is much simpler. The high heat generated by the burning powder is burning the lube, which is basically wax and grease. When the lube burns it smokes. I would imagine a lubed powder coated bullet would smoke also, haven't tried it, but I bet some have. What I do know is every lubed bullet I have tried over the years smokes and my powder coated bullets do not; using the same guns, same cases, same powder and primers with the only change being the bullet.

[gloob]

Ok, fine. The bread I buy at my grocery store isn't sliced. Got it. Your manual bread-slicing invention is the only thing that makes sliced bread. Thanks. You have verified this by failing to locate the sliced bread in the bread isle for your whole life. Got it. Party on.

If, OTOH, you're willing to turn your head 3 inches and look where I have told you, you might find it.

[dragon813gt]

You buy bread. Talk about a waste of money. Especially the more expensive pre sliced variety

[mongoose33]

Gloob, thank you. I've just scanned through your response, but I appreciate the effort and time it took to put your thoughts down.

Above all, I'm simply trying to learn here. I don't care if people like PC'ing or don't like PC'ing--I don't have to shoot their rounds, they don't have to shoot mine. But trying to learn how to reduce smoke is almost certainly going to result in a greater understanding by me.

The idea of an incompletely sealed chamber allowing hot gases to surround the lube before the boolit makes it into the barrel--very interesting.

I'm going to go back and study that--one of the things I love about doing this as a hobby is the learning. Seems like I'm going to enjoy this.

Goose

[mongoose33]

Gloob, thought a lot about your post, and I made up some rounds tonite to hopefully test the theory.

On the presumption that as the boolit leaves the case hot gases are melting and burning the lube, I made up 10 cast/lubed rounds w/ the boolit just kissing the lands. I made up 5 more w/ the PC instead of the lube, then some more PC .03 shorter than that as well.

I probably won't get out until Saturday; I will, of course, report back. BTW this is in 9mm, the boolits are fairly soft alloy, and sized at .357. I've tried .358 but just can't get them to chamber reliably.

[gloob]

I hope you have step 3 covered. That's the most important one.

Notice it doesn't much matter how long is your OAL, or how far from the lands. That's a parameter that shouldn't do too much in a normal chamber, where the chamber is pretty tight in at least the casemouth or in the leade/freebore. I do a lot of my shooting with Glocks, and I can't get anywhere near the lands in a Glock bore.

If you wanna plug the bore better, you want to make sure the bullet is not swaged, though. Expander diameter = bullet diameter. Very important. There are only 3 rules of Wonderbread. If you omit one, you're on your own. Take care of these 3 rules and you will most likely have no problem with smoke.

fairly soft alloy, and sized at .357. I've tried .358 but just can't get them to chamber reliably.

Good, they're starting out big enough. Next step is to ensure the full diameter driving band of the bullet is not compromised.

I know you are not stupid. If it seems like I'm telling Michael Jordan how to tie his shoes, please forgive me. This expander thing is very important, IME, especially in 9mm, particularly with soft alloy, and especially if you are finding you have to go with +2 mil bullets. Use an expander that measures at least 356 for your bullets, if not 357, and which goes at least as deep as the bullet does. The expander that came with your die most likely measures only .353" and too short, anyway. It's just a jacketed bullet flare die, and that's all it's good for. If you use the right expander, you might find out that you never needed to go up to 357 in the first place.

Even if you pull a bullet and measure it the same, you may be missing something. A tight case is NOT a bullet sizer. It doesn't make the bullet into a smaller perfect circle. If the case is too tight, the bullet can measure the same in diameter all the way around except with a flat spot, for instance. And the full length of the driving band is important. It's not enough to have just one spot on the bullet at full diameter.

[mongoose33]

I'm not sure how I would alter the casemouth expansion in a 9mm case. I use a cone-shaped expander on my powder drop--I whomp up a bunch of sized, deprimed, primed, and casemouth expanded cases on my progressive which I then use when I make up test loads by hand.

The cases are open on the top enough to seat the boolit without shaving lead off the side of the boolit, but I have no way of altering how much it's expanded unless I create a very large belling of the casemouth. Too much more and I'd reduce the neck tension--and as the 9mm case is tapered, going into the case further simply reduces the part of the case gripping the boolit.

I just tried the casemouth expansion die that comes w/ my 9mm dies, and I can't see any difference in the belling of the casemouth. I tried seating a few boolits, couldn't discern any difference in the pressure required to seat.

I pulled a few boolits I'd seated in dummy rounds, both before and after crimping--there is some swaging going on w/ the crimp process, but little or none from seating the boolit in the case. I did note, however, that the pulled boolits weren't perfectly round, as you said, there was a flat spot.

With the ones which were crimped, there was some swaging. I can't get them to chamber w/o that level of crimp, which means either I need a HARDER alloy, or a smaller-diameter boolit. Or something.

I appreciate the feedback!

[Dragonheart]

Gloob, Have you considered that the reason you 10 mm doesn't smoke with 10 mm cases is because you are using a case that is long enough to fit the chamber properly and headspace off the mouth of the case, as all these straight walled cases were designed to do? Why would you shoot a short 40 case in a 10 mm when you would be headspaceing off the extractor? Additionally, I can tell you from an accuracy standpoint a short case will give you larger groups than a case of the proper length.

[captaint]

I use a Star for lubing & sizing and find that perfectly enjoyable. That's just me. There is one thing I don't understand, though. Why all the talk about dies gummed up ??? I don't gum any dies up. I stopped using tumble loobing methods for that reason, but other than TL'ing, I don't understand how we're messing up our dies. I guess it's just that. Hey, as long as everybody is having fun, do what you do...

[Dragonheart]

I'm not sure how I would alter the casemouth expansion in a 9mm case. I use a cone-shaped expander on my powder drop--I whomp up a bunch of sized, deprimed, primed, and casemouth expanded cases on my progressive which I then use when I make up test loads by hand.

The cases are open on the top enough to seat the boolit without shaving lead off the side of the boolit, but I have no way of altering how much it's expanded unless I create a very large belling of the casemouth. Too much more and I'd reduce the neck tension--and as the 9mm case is tapered, going into the case further simply reduces the part of the case gripping the boolit.

I just tried the casemouth expansion die that comes w/ my 9mm dies, and I can't see any difference in the belling of the casemouth. I tried seating a few boolits, couldn't discern any difference in the pressure required to seat.

I pulled a few boolits I'd seated in dummy rounds, both before and after crimping--there is some swaging going on w/ the crimp process, but little or none from seating the boolit in the case. I did note, however, that the pulled boolits weren't perfectly round, as you said, there was a flat spot.

With the ones which were crimped, there was some swaging. I can't get them to chamber w/o that level of crimp, which means either I need a HARDER alloy, or a smaller-diameter boolit. Or something.

I appreciate the feedback!

From an accuracy and reliability standpoint, there is no reason to oversize your bullets. Once the bullet fills the grooves of the bore is has sealed in the expanding gases, adding additional diameter only increases the pressure buildup and degrades accuracy. Ideally, if a bullet that can be seated 3 to 5 thousands off your lands will give you the best accuracy and still provide the necessary "jump" to advert a pressure spike. Obviously, all bullet designs cannot be seated this way and still fit in the magazine of the handgun. As you can imagine an oversize bullet jammed into the lands will create a pressure spike when fired; taken to the extremes it's called a grenade.

From testing I have found 0.750 the be the best 9 mm OAL case length from an accuracy standpoint, shorter cases will give larger groups. Unfortunately, most 9 mm cases are shorter then .750. Repeated firings will eventually lengthen the case, but some are so short they will never make the .750. Cases too long should be trimmed as they can create over-pressure problems.

[Beagle333]

I use a Star for lubing & sizing...... I stopped using tumble loobing methods for that reason, but other than TL'ing, I don't understand how we're messing up our dies.

If I use my Star (properly), I don't have lube on the nose and base. True! So that is a bonus over the shove-it-down, pull-it-up loobers, but I use the Hornady dies with the sleeves in them (Custom Grade - New Dimension, my favorites), and I'll still get lube all in those sleeves pretty fast. I guess some others could scrape some off when seating and then get that in their crimping die.

[retread]

Seems some like folks have thing for "one size fits all", me, I PC, use lubes in my Lyman sizers, try new tumble lube recipes (like Ben's LL). The joy is in the journey, I am not going to dismiss new ideas because I "know" what works best. Each time I read these posts I glean a little more insight to what others are doing and I benefit by it. The folks that are so animate that there way is best are sadly missing out on what could be better way to approach an old problem. I thank all for keeping this old brain active.

[Deadpool]

Black, or in the case of bullets a shiny silver, is a classic look and is never out of style.

I've stuck with black and white. White tends to pick up lead from the shaking and turns grey, when using wet-coat method anyway. I think the next color I'll try is "Safety Blue." lol. I don't know if that's irony, or sacrilege.

[Dragonheart]

If I use my Star (properly), I don't have lube on the nose and base. True! So that is a bonus over the shove-it-down, pull-it-up loobers, but I use the Hornady dies with the sleeves in them (Custom Grade - New Dimension, my favorites), and I'll still get lube all in those sleeves pretty fast. I guess some others could scrape some off when seating and then get that in their crimping die.

This has been my experience, also I hate taking my micrometer seating die apart to clean out the lube as you never get it exactly back where it was, so my notes about seating depth of certain bullets are nil. When the lube builds up in my crimp die then my OAL is shot. Maybe others don't have my problems or don't want to talk about it or don't care. As for me I am into accuracy, so these things make a difference. These are some of the reasons I got out of casting in the first place. Now powder coating has opened up a whole new dimension for me. For those that are happy with status quo, more power to you.

[Garyshome]

Got this PC powder and don't have anything else to use it for.

[gloob]

but I have no way of altering how much it's expanded unless I create a very large belling of the casemouth. Too much more and I'd reduce the neck tension

I use a cone-shaped expander on my powder drop

And how do you think I knew you were using something like this? If you're curious about fouling, smoke, or accuracy (or if you are giddy as a school girl over powder coat) out of a locked breech gun, esp in 9mm, it's 99% likely you're doing this part wrong.

The way to do it is replace your cone-shaped expander with a proper cylindrical expander of .356". Maybe you can adapt your powder measure to use a Lee flare/powder-thru die and to use an NOE 356/360 powder through P plug. If you're using a proprietary press or setup, like a square deal, well, then you might have to find a machinist to make something up. If this seems like too much cost and effort, then your priorities are different. If you ever try it, your priorities might change. It really is that important, and it really is this simple. Whether you're shooting regular cast or PC, the case must be sized/expanded properly for the bullet as per how the black powder guys do it, if you want the same or better accuracy as with jacketed bullets. If your sizing die is loose enough, you might be lucky and are already getting this with out-of-the-box dies, but in 9mm this is a snowball's chance in hell.

If you don't believe enough to bother trying, then perhaps you could try sorting your cases and shooting for groups. You will likely find your thinner walled cases shoot tighter groups with cast or pc'd bullets, esp at farther ranges. But there's a common theme where anyone tells me that they have loaded for 83 years and simply can't get the results I speak of with cast bullets. I ask about their expander, and they make qualified excuses.

From an accuracy and reliability standpoint, there is no reason to oversize your bullets. Once the bullet fills the grooves of the bore is has sealed in the expanding gases, adding additional diameter only increases the pressure buildup and degrades accuracy.

I've heard this said many a time, but I have never seen a reference to any kind of supporting evidence. The more you fill the chamber/bore, the less gas blowby of the bullet before it plugs the bore. This could mean less variation in muzzle velocity and this mechanism might increase accuracy. There are some rifles and military big guns/cannons that have utilized a greatly choked barrel on purpose, and this have not shown to decrease accuracy to any significant degree.

Initial burn rate and peak pressure are increased. A roll crimp increases these things too, and a roll crimp is not normally associated with lower accuracy, in general. In specific cases, it has been shown to increase accuracy, even. Of course, your charge and powder selection for maximum accuracy would account for the oversized bullet and higher peak pressure.

[Dragonheart]

Yep Tried it and no it does not smoke worse than a regular PC bullet.

Well now we know.

[Deadpool]

Yep Tried it and no it does not smoke worse than a regular PC bullet.

Hmm, what lube are you using? You can smell my lube after each shot, and the smoke is a bit heavier. It will jam up the gas piston in a semi, so I switched to PC for most guns.

[Love Life]

PC and HT coated bullets really shine for me on indoor ranges where a fast string of traditionally lubed bullets can create quite the cloud.

For outdoor ranges, a tumble in 50/50 LLA/MS or BLL sho' does make production fast!