Accuracy of powder coated vs. conventionally lubed bullets

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Tom G posted this 22 July 2020

I'm just starting with pc'ing pistol bullets. So far, after limited testing on a Ransom Rest with a Browning Hi Power in 9MM, I'm not seeing anything to write home about. 

 So far, I've shot loads with Universal powder from 3.3 thru 3.7 grains with a 126 gr. bullet at 11 BHN hardness.  Groups haven't been as good as with conventionally lubed bullets. Using my Quick Load Program and by comparing velocities of those predicted to those measured, the pc's bullet shoot slower than predicted. I intend to increase the charges up to 4.2 grs. in increments of .1 grain to see if things improve with hotter loads. That will be my next test. 

So far, I've observed that the barrel had no leading at all but was fouled in the first inch and a half in front of the chamber with some unknown substance that came out easily with a few passes with the brass brush. The gun was very sooty around the chamber area and barrel that I don't normally see. This may be due to the cautious approach I made with powder charges that don't burn completely. I dunno.  

Has anyone done an accuracy comparison of pc's bullets vs. regular lubed bullets in the same gun?  Did you get the same velocity?  Was the accuracy comparable? 

My initial impression is that these pc'd bullets don't have the same bore friction as regular bullets. The fact that the don't go as fast indicates that they aren't developing the same chamber pressure due to less initial engraving forces and less friction going down the barrel. 

If anyone has done any kind of a study on these lines it would be good info to share. If anyone is interested, I'll post the results of the next test taking this load up to a full case of powder (100 % load density)  to see what happens. Quick Load program predicts 4.2 grains of Universal to be a full case with 99+ % powder burn in a 4.8 inch barrel. Predicted peak chamber pressure is ~ 25,300 psi. which is way below the 35,000 psi limit for this cartridge. 

This gun has shot groups under 2 inches at 25 yards with the same bullet conventionally lubed. So far, they've been 3 to 5 inch groups with pc'd bullets. 

 Tom

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MP1886 posted this 02 December 2021

Powder coating makes a jacket. Polyester powder is about the same hardness as copper but more brittle. The coating is also very, very slippery and changes the whole dynamic of the internal ballistic system. You can work with, or against what a powder coated rifle bullet wants to function and shoot well, but to make any sort of direct accuracy comparison between a lubricated bullet and a powder coated bullet (usually using parameters which work best for the lubricated one) isn't very informative. As to fouling with powder-coated bullets, I find it less than with copper-jacketed because there is no copper fouling and after one shot or 500 there is absolutely no change in bore condition. I do clean all my guns after shooting powder-coated bullets because there is no protective lube coating and not much in the way of seasoning. One patch of Ed's Red and two clean, dry ones and done. Next shot from a cold bore goes dead center of the group, multiple rifles and multiple test prove it without a doubt. A cold, dirty bore will throw the first shot to the edge of the normal group dispersion bur almost never beyond.
Just trying to help you out my friend, although you don't need it.  It's just that you're not on this forum daily. 

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Geargnasher posted this 02 December 2021

Powder coating makes a jacket. Polyester powder is about the same hardness as copper but more brittle. The coating is also very, very slippery and changes the whole dynamic of the internal ballistic system. You can work with, or against what a powder coated rifle bullet wants to function and shoot well, but to make any sort of direct accuracy comparison between a lubricated bullet and a powder coated bullet (usually using parameters which work best for the lubricated one) isn't very informative.

As to fouling with powder-coated bullets, I find it less than with copper-jacketed because there is no copper fouling and after one shot or 500 there is absolutely no change in bore condition. I do clean all my guns after shooting powder-coated bullets because there is no protective lube coating and not much in the way of seasoning. One patch of Ed's Red and two clean, dry ones and done. Next shot from a cold bore goes dead center of the group, multiple rifles and multiple test prove it without a doubt. A cold, dirty bore will throw the first shot to the edge of the normal group dispersion bur almost never beyond.

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Geargnasher posted this 02 December 2021

EXACTLY what I was going to say. You never encounter discussions about lubricating jacketed bullets to keep fouling soft or for any reason other than academics (yes, it has been done and tested, not counting the molybdenum coating process).

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MP1886 posted this 02 December 2021

OU812  let me ask you this, do you use lube on your jacketed bullet loads?   Nuff said!

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Spindrift posted this 02 December 2021

I’ve done some limited testing with tumble lube overcoat on PC bullets. The lube was my standard mix of Xlox, and a liquified hard wax («boat wax». I found accuray was unchanged, or slightly worse.

I have found powder fouling, or any kind of fouling for that matter, to be a non-issue with my PC bullets. The barrel actually seems cleaner than when using jacketed bullets, for some reason. 

I usually run a patch with Ed’s red down the barrel, followed by a dry patch, just to keep an eye on things. I suspect I could just stop cleaning. 

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MP1886 posted this 02 December 2021

Anybody try lubing their powder coated bullets. It should help keep powder fouling softer. Maybe accuracy would be better.
Gear is my go to man on powder coat.  He's knows a pretty good bit about and he told me not to lube them.  He gave it a good test.  Why he hasn't chimed in on that other then missing it I don't know. 

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OU812 posted this 02 December 2021

Anybody try lubing their powder coated bullets. It should help keep powder fouling softer. Maybe accuracy would be better.

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Geargnasher posted this 02 December 2021

"Remember Gear, seat to engrave the rifling is kntergarden cast shooting, doesn't work for high velocity. "

That was exactly my point.

"Fitted to the throat" also means different things to different people and I am perplexed by how seldom that topic comes up on cast bullet discussion boards.

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MP1886 posted this 01 December 2021

Tom G mentioned base flashing and it is definitely a problem which affects accuracy. Cure this by using a bevel-based bullet which casts very round. Also, for bottleneck rifle cartridges and medium velocity loadings, one can use bullets designed for gas checks but without the checks; the clean base band will make its exit square to the crown regardless of any flashing or slight imperfections on the base of the check shank. One more thing about powder-coated cast bullets and accuracy: the bullet must fit to the gun. With the exception of revolvers, the requirements of fit are much different in some respects than lubricated bullets and similar in only two (must be large enough to obturate the bore and is best if they are fitted to the throat). I outlined this earlier in the thread. If you think "fit" means "size to .311" and seat to engrave the nose", you're going to have a lot of trouble with this whole PC thing.
Remember Gear, seat to engrave the rifling is kntergarden cast shooting, doesn't work for high velocity. 

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Geargnasher posted this 01 December 2021

"IMHO oversizing wrecks accuracy"

Only if you don't do it correctly. People have been nose-bumping, swaging, drawing in a form die, and all sorts of other things and winning matches with such methods for over a century.

Personally, I like to make whole-bullet form dies for my Lyman 45 and use ejector (I) punches which I have counterbored to match bullet points with my lathe. I size nose-first after applying/crimping gas checks, presizing in a Lee-type sizing die, and powder coating. The interior for of the H die is reamed with a D-reamer turned and ground to match the throat of the rifle for which the bullet is intended.

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Geargnasher posted this 01 December 2021

Tom G mentioned base flashing and it is definitely a problem which affects accuracy. Cure this by using a bevel-based bullet which casts very round. Also, for bottleneck rifle cartridges and medium velocity loadings, one can use bullets designed for gas checks but without the checks; the clean base band will make its exit square to the crown regardless of any flashing or slight imperfections on the base of the check shank.

One more thing about powder-coated cast bullets and accuracy: the bullet must fit to the gun. With the exception of revolvers, the requirements of fit are much different in some respects than lubricated bullets and similar in only two (must be large enough to obturate the bore and is best if they are fitted to the throat). I outlined this earlier in the thread. If you think "fit" means "size to .311" and seat to engrave the nose", you're going to have a lot of trouble with this whole PC thing.

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max503 posted this 26 August 2021

Thanks.  I want bullets that drop .224 from the mold.  Looks like those Arsenal Molds are affordable at $68.  

IMHO oversizing wrecks accuracy.  I'm trying to avoid that and find a plain-base bullet I can PC for my Tikka 223.

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Spindrift posted this 24 August 2021

I'll keep you posted. The first bullets have soon reached maturity. I'll try to squeeze in a shooting session during the hunting season.

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max503 posted this 24 August 2021

I would be interested to know how those 45 grain, 224 bullets worked out.

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Spindrift posted this 16 August 2021

Hello, Mashburn- and thank you for your kind words!

I’m glad to hear the coating technique is working out so well for you! I’ve had good results with several powders, but my current favourite is Easwood «Ford, light blue». It has exceptional adhesive properties, and seems to float very well.

 

I’m about to try my first grooveless bullet. This is the Arsenal 225-45, an bevel- base mould that basically looks like.... a bullet! Arsenal moulds allow you to specify the size you want. I asked for a .224 mould, to allow for a coat- without having to size to much afterwords. In a week or two, the first bullets have reached «maturity», and I will let fly from my CZ527 in .222rem. I’ll keep you posted!

 

The 225-45 is the one on the left. The color is a mix, 3:1:1 Ford light blue/Chrysler orange/ gloss white

 

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mashburn posted this 16 August 2021

Hello Spindrift,

I think that you are right when  when you say  that powder coating changes the geometry of a bullet. Another thought of mine is how many people are shooting bullets that do not fit their rifle. For instance, I have several 30 Caliber molds, all of which are bore riders. I also have a lot of 30 Cal. rifles. Some of my bore riding bullets, when coated and sized, have noses that won't fit my rifle bores because the nose of the bullet is too large after coating and in some of my rifles they  fit perfectly. I'm referring to fit as the nose of the bullet fitting the bore. I don't attempt to load rounds for those rifles  whose bores are too small for the nose of that particular rifle, I have 4 30-06 rifles but by selecting bullets from the different molds I am able to fit a bullet to all of my 30-06 rifles.

Another thought of mine is, how many of these shooters who are having leading problems and poor accuracy are seating the bullet too deep in the chamber and scraping coating off of the bullet, when they are loading. One more thing, some of the bullets pictured, that were used in tests, to me they don't appear that the coating flowed correctly and I wonder if the baking heat was not high enough. The pictures of your bullets that you have pictured look exactly like mine. You are having very good accuracy and I'm having the same. I use nothing but Eastwood Jet Black powder, but am going to order some of Eastwood's gloss red. I hope I'm not making a mistake.

You gave me a lot of good information when I first starting to coat bullets and I really appreciate it. I spent over a year trying to master making coated bullets before I ever took a rifle to the range and fired them. I have learned how to control the thickness of coating to the point that I may have only 1 or 2 that vary in a hundred bullets. During that time, I learned some knowledge that most people would never think of. I shot some .17 cal gas checked ,powder coated bullets last fall. That was the first time that I had fired any of the .17's I have three groups recorded; one was under 1/2 inch and the other 2 groups were slightly over 1/2 inch. These were fired at 100 yards and they were zipping. I'm not going to state what the velocity actually was because most people wouldn't believe it.

Again, I really appreciate the info. that you gave me to get me started.

Thanks,

Mashburn

David a. Cogburn

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Boschloper posted this 16 August 2021

Ken: The last batch of 429421 that I pc'd I did nose down and they came out very nice. There was just a little of the flashing that Tom refers to, but it was on the nose and the base was very uniform. I line my pan with woven teflon oven liner from Walmart. It leaves a woven pattern on the part of the bullet that it touches.

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JohnForrest posted this 15 August 2021

 I hope this topic doesn't die. As a new caster I started out powder coating and am now getting ready to start greasing up some plain bullets just so I know how. I don't want to miss out on something.

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Ken Campbell Iowa posted this 24 July 2021

 ... since peculiarities at the front of the bullet seem to be much less detrimental to accuracy ...

maybe pc them nose down ... holding them by the nose ... would give better bases ....

*************

anybody examined the Federal lipstick bullets for quality of coating ? ...  or tested them in an accurate gun ? 

ken

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Tom G posted this 23 July 2021

One thing I've notices on my pistol bullets is that some of them have a flash of cured polymer on the base edge of the bullet. I'm using non stick alum.  foil under them and as the powder melts, it sometimes runs down and forms a flashing on the base edge of the bullet. 

Also, I don't think I'm getting the same thickness of powder on all of the bullets. This could be the cause of the flash at the base. I run all my bullets through a Lee push through sizer die and it doesn't  always eliminate the flash on the edge. I plan to run a test by shooting ones with flashes against ones with clean edges on the bases. Sometimes the flashing comes off when it goes into the die but not all the time. 

Maintaining the integrity of the edge of the base is very important to accuracy so I tossed this out in case anyone else is looking for the reason for fliers with coated bullets. 

I was having trouble with some of the bullets having the alum. foil stick to the base of the bullets so I tried using some parchment paper instead of foil and I didn't see any sticking or flashing. I will continue to look into that as time permits and report the results to this group.  

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