powder coating bullets
- Thread starter smooth.pull
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the cast bullet people have been doing it for some time
http://castboolits.gunloads.com/forumdisplay.php?184-Coatings-and-Alternatives
http://castboolits.gunloads.com/forumdisplay.php?184-Coatings-and-Alternatives
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What advantages do you envisage? Can the coating thickness be controlled with any consistency as we all know or have read about the affect even small diameter changes have on shot accuracy?
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We did some professional testing back in the 90's...At the time we were trying to find out whether or not this lubricant would improve accuracy...We used Molybdenum and the coating was done by placing the pellets in a case tumbler (vibrating machine) loaded with media and Moly...
The results were NOT favorable: The velocity diminished substantially but this was not an issue in a gun where the velocity could be compensated...The main issue with this process was the mess the Molybdenum left all around the gun, transfer ports, breach, etc. and around fingers...Very messy!
Accuracy wise, we found that once the velocity was adjusted there were no plus or minuses and this was the end of moly coating pellets...
In an effort to avoid the external Moly mess, we then coated the inside of the barrel only as it is done in centerfire guns and shot pellets without lubrication (Washed-Degreased)... Again, the velocity needed to be adjusted upwards and there were no accuracy pluses or minuses.
We finally shot pellets out of the tin (factory lubed) with a moly coated barrel...The only difference from the testing as explained above was a barrel getting dirty much sooner, and accuracy didn't last. The reason for this was obviously the grime that the moly and lube formed inside the barrel.
Coating soft lead pellets with substances that harden one way or the other defeats the benefits of soft lead and this effect diminishes accuracy...This can clearly be seen testing cooper coated pellets vs. their uncoated counterparts ...Softer lead makes a better seal with the barrel and makes the necessity of deeper rifling unnecessary and this works in favor of accuracy...
While I have not tested extensively, I have found that softer pellets tend to be more accurate than harder ones, but then it is easier to produce better finished pellets when the factories use harder lead alloys...A better finished pellet should be by definition more accurate but this is not always true with harder alloys...
At the velocities we shoot pellets there is basically no leading (buttering) inside the barrel, and lubrication fulfills two purposes: To maintain a barrel cleaner longer and to help with velocity consistency...If anyone cleans a barrel with acetone or lacquer thinner and shoots washed unlubed pellets, the spread will be larger and the barrel will get dirty sooner.
Washed degreased pellets work well with a little lubricant of pretty much any kind...We tried from formulas involving tallow and beeswax as used in .22 RF benchrest ammo to simple motor oil to dry lubricants (Teflon and other)...All pretty much provide the same results and the key issue to remember is that "Little is allways better than too much"...A few drops of lubricant go a long way and the pellet contact surfaces needing lubrication are only around the widest areas of the head and skirt, nothing else needs lubricant and make sure you don't lube the hollow part of the pellet.
Regards,
AZ
The results were NOT favorable: The velocity diminished substantially but this was not an issue in a gun where the velocity could be compensated...The main issue with this process was the mess the Molybdenum left all around the gun, transfer ports, breach, etc. and around fingers...Very messy!
Accuracy wise, we found that once the velocity was adjusted there were no plus or minuses and this was the end of moly coating pellets...
In an effort to avoid the external Moly mess, we then coated the inside of the barrel only as it is done in centerfire guns and shot pellets without lubrication (Washed-Degreased)... Again, the velocity needed to be adjusted upwards and there were no accuracy pluses or minuses.
We finally shot pellets out of the tin (factory lubed) with a moly coated barrel...The only difference from the testing as explained above was a barrel getting dirty much sooner, and accuracy didn't last. The reason for this was obviously the grime that the moly and lube formed inside the barrel.
Coating soft lead pellets with substances that harden one way or the other defeats the benefits of soft lead and this effect diminishes accuracy...This can clearly be seen testing cooper coated pellets vs. their uncoated counterparts ...Softer lead makes a better seal with the barrel and makes the necessity of deeper rifling unnecessary and this works in favor of accuracy...
While I have not tested extensively, I have found that softer pellets tend to be more accurate than harder ones, but then it is easier to produce better finished pellets when the factories use harder lead alloys...A better finished pellet should be by definition more accurate but this is not always true with harder alloys...
At the velocities we shoot pellets there is basically no leading (buttering) inside the barrel, and lubrication fulfills two purposes: To maintain a barrel cleaner longer and to help with velocity consistency...If anyone cleans a barrel with acetone or lacquer thinner and shoots washed unlubed pellets, the spread will be larger and the barrel will get dirty sooner.
Washed degreased pellets work well with a little lubricant of pretty much any kind...We tried from formulas involving tallow and beeswax as used in .22 RF benchrest ammo to simple motor oil to dry lubricants (Teflon and other)...All pretty much provide the same results and the key issue to remember is that "Little is allways better than too much"...A few drops of lubricant go a long way and the pellet contact surfaces needing lubrication are only around the widest areas of the head and skirt, nothing else needs lubricant and make sure you don't lube the hollow part of the pellet.
Regards,
AZ
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Thanks AZ! That is very helpful! Appreciate you sharing your experience. Saves me a lot of work. Ha Ha!
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Coating copper-clad bullets has been done for many years in the powder-driven, reloading marketplace. While several forms of moly (molybdenum disulfide or other derivative) have been very popular, Danzac (tungsten disulfide), has been one of the more popular coatings. Variations of it, are still being used by several commercial ammunition manufacturers. Unlike moly, it doesn't rub off easily, and doesn't require polishing after the coating process.
Either product is a whole lot slippery than uncoated bullets. As a result, reloading parameters have to be adjusted to compensate for the drop in friction (slower FPS) From experience, at least with an Ackley-Improved, 22-250, the nominal loadings can be increased by about 10% depending on the original loading parameters.
I'm aware of a lot of attempts to use coatings on lead alloy bullets (jacket-less), but I don't think the results were all that encouraging. After all, most lead alloys are fairly-good anti-friction materials (think babbitt bearings). Nonetheless, you bring up an interesting subject.
I have all the necessary equipment to Danzac-coat thousands of pellets. Perhaps I should do that, just to see what happens. However, again based on experience, the driving force will have to be increased if one is to maintain some given velocity (more pumps, higher chamber pressure, however it is done).
There is another issue, but to be honest I'll have to do some research. Copper against steel, is different than copper against stainless steel, at least in the stainless steel used in some barrels and/or inserts. This makes me wonder about a lead alloy vs. a brass barrel as in a 397 or 392 Benjamin?
I wish folks wouldn't do this to me! After all, I am really trying hard to remain retired!
Either product is a whole lot slippery than uncoated bullets. As a result, reloading parameters have to be adjusted to compensate for the drop in friction (slower FPS) From experience, at least with an Ackley-Improved, 22-250, the nominal loadings can be increased by about 10% depending on the original loading parameters.
I'm aware of a lot of attempts to use coatings on lead alloy bullets (jacket-less), but I don't think the results were all that encouraging. After all, most lead alloys are fairly-good anti-friction materials (think babbitt bearings). Nonetheless, you bring up an interesting subject.
I have all the necessary equipment to Danzac-coat thousands of pellets. Perhaps I should do that, just to see what happens. However, again based on experience, the driving force will have to be increased if one is to maintain some given velocity (more pumps, higher chamber pressure, however it is done).
There is another issue, but to be honest I'll have to do some research. Copper against steel, is different than copper against stainless steel, at least in the stainless steel used in some barrels and/or inserts. This makes me wonder about a lead alloy vs. a brass barrel as in a 397 or 392 Benjamin?
I wish folks wouldn't do this to me! After all, I am really trying hard to remain retired!
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You also brought up a very interesting point Alan and this is the fact that Lead doesn't adhere to Brass or at least not even close to the same extent as it does adhere to steel...This is why Brass barrels that the industry has used for decades don't need frequent cleaning...But this is also where the confusion and myths about pellet gun barrels not needing cleaning comes from.
Regards,
AZ
Regards,
AZ
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That is some interesting thoughts on the subject , I know on cast powder burning bullets you have to resize them but air gun pellets with a light powder coat , is it worth it ?
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Lead doesn't, but lead oxide does adhere, at least to a greater extent. I don't have my alloy book handy, so I can't say what the affinity is, one over the other.
While I was taking a shower (early because of the "ticky-teeters"), I was thinking about other pellet materials. We all know that lead shot is no longer allowed for upland game species, and a lot of states, including New Mexico where I live, has additional moratoriums against lead shot. But what about the heavier alloys of bismuth, tungsten, and even depleted uranium?
I would think, in the not too distant future, that lead pellets might be outlawed by the coercive utopian left! While I hope not, one never knows.
While I was taking a shower (early because of the "ticky-teeters"), I was thinking about other pellet materials. We all know that lead shot is no longer allowed for upland game species, and a lot of states, including New Mexico where I live, has additional moratoriums against lead shot. But what about the heavier alloys of bismuth, tungsten, and even depleted uranium?
I would think, in the not too distant future, that lead pellets might be outlawed by the coercive utopian left! While I hope not, one never knows.
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¿Can you imagine having to buy $25.00 and up tins of Bismuth - Tungsten "Environmentally Friendly" pellets?
I hate to pay $44.00 for a box of 12 ga.Tungsten shells when the same cartridges can be bought in lead for $6-7 dollars/box (Premium cartridges), but then I understand the effort in cleaning and keeping the environment clean.
I wish the industry experimented with copper for keeping the costs down...Copper according to the table is only 27% lighter than lead. Tungsten is 73% heavier and Uranium is also 67% heavier...The Industry would have to adjust the profiles of the pellets and maybe the bore ratios given the larger mass and hardness of these metals...
Combining heavier metals encapsulated in a plastic jacket (Sabot) would help in balancing the equation (mass/profile/length) and would help to maintaining our barrels clean, but the issue is: At what COST ???
There are a few of these plastic/metal (lead) combination pellets out there that can easily be switched to plastic/non toxic metals, but current pricing is just ridiculous...At about $9.00 for 100 and similar prices I don't believe any of us will be happy.
The good thing is that a change like this will keep all of those Ballisticians pretty busy and out of trouble don't you think? LOL
Regards,
AZ
I hate to pay $44.00 for a box of 12 ga.Tungsten shells when the same cartridges can be bought in lead for $6-7 dollars/box (Premium cartridges), but then I understand the effort in cleaning and keeping the environment clean.
I wish the industry experimented with copper for keeping the costs down...Copper according to the table is only 27% lighter than lead. Tungsten is 73% heavier and Uranium is also 67% heavier...The Industry would have to adjust the profiles of the pellets and maybe the bore ratios given the larger mass and hardness of these metals...
Combining heavier metals encapsulated in a plastic jacket (Sabot) would help in balancing the equation (mass/profile/length) and would help to maintaining our barrels clean, but the issue is: At what COST ???
There are a few of these plastic/metal (lead) combination pellets out there that can easily be switched to plastic/non toxic metals, but current pricing is just ridiculous...At about $9.00 for 100 and similar prices I don't believe any of us will be happy.
The good thing is that a change like this will keep all of those Ballisticians pretty busy and out of trouble don't you think? LOL
Regards,
AZ
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Maybe you could elaborate on this statement as at 900+fps my LW barrels need cleaning every 100 shots, especially in the choke. Surely this is due to leading ?
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"Maybe you could elaborate on this statement as at 900+fps my LW barrels need cleaning every 100 shots, especially in the choke. Surely this is due to leading ?"
Bluestone:
I will do my best to answer your question..,.
Lead fouling doesn't happen in airguns as it happens in firearms...In a firearm we get an accumulation of small very thin layers (buttering ) derived of lead being in contact with high temperatures of burnt powder, hot gases and friction inside the barrel...Keep in mind that lead melts at around 620 F so it doesn't take much heat to "lead foul" a barrel. Then those lead layers are removed by a good solvent to loose them up combined with some scrubbing, usually a bronze brush or similar. We have that the hotter a firearm barrel gets, the more fouling it promotes...
An airgun barrel is missing the hot temperatures of burning powder, gases and friction combined.. Airgun barrels don't get hot and this is a plus, then 900 fps. is not enough velocity for a COLD pellet to soften enough (friction) for layering an airgun barrel...Nevertheless, It is enough velocity for fouling a rim-centerfire barrel.
Airgun barrels get grime from lead dust particles combined with wax/lubricants that manufacturers use during the manufacturing process and for preventing pellets from oxidizing...But this lead grime is not Lead Fouling per se...
Note: The white powder that is seen in old pellets is Lead Oxide and this is what manufacturers try to delay using wax-lubricants....
Accuracy deteriorates when this grime gets into the grooves of the rifling...Airguns have a very small bore ratio (dimensions of grooves to lands) and it doesn't take much for saturating those grooves...In other words, rifling in airguns is very "Shallow" and it becomes filled pretty easy. Washing and then either waxing or lubricating our pellets is a good effort for reducing grime and prolonging cleaning intervals.
Airgun barrels can not use DEEP rifling because it would destroy accuracy (deep marks on pellets), this is why rimfire & centerfire barrels DON'T work well with airgun projectiles, specially with the Diabolo shaped ones.
Accuracy in an airgun barrel is restored after passing 2-3 patches until they come out clean...Some people use plain dry patches, others use felt pellets and some other shooters use oil.solvents, etc.on one patch and then pass 2-3 dry ones...All methods are good and at this time accuracy is restored and the barrel is clean...
If there were any "lead fouling" as it happens in firearms, 2-3 dry patches would never remove a single layer of lead...We would have to use lead solvents and some kind of brushing...But then brushing would shorten the lives of our barrels...
Best regards,
AZ
Bluestone:
I will do my best to answer your question..,.
Lead fouling doesn't happen in airguns as it happens in firearms...In a firearm we get an accumulation of small very thin layers (buttering ) derived of lead being in contact with high temperatures of burnt powder, hot gases and friction inside the barrel...Keep in mind that lead melts at around 620 F so it doesn't take much heat to "lead foul" a barrel. Then those lead layers are removed by a good solvent to loose them up combined with some scrubbing, usually a bronze brush or similar. We have that the hotter a firearm barrel gets, the more fouling it promotes...
An airgun barrel is missing the hot temperatures of burning powder, gases and friction combined.. Airgun barrels don't get hot and this is a plus, then 900 fps. is not enough velocity for a COLD pellet to soften enough (friction) for layering an airgun barrel...Nevertheless, It is enough velocity for fouling a rim-centerfire barrel.
Airgun barrels get grime from lead dust particles combined with wax/lubricants that manufacturers use during the manufacturing process and for preventing pellets from oxidizing...But this lead grime is not Lead Fouling per se...
Note: The white powder that is seen in old pellets is Lead Oxide and this is what manufacturers try to delay using wax-lubricants....
Accuracy deteriorates when this grime gets into the grooves of the rifling...Airguns have a very small bore ratio (dimensions of grooves to lands) and it doesn't take much for saturating those grooves...In other words, rifling in airguns is very "Shallow" and it becomes filled pretty easy. Washing and then either waxing or lubricating our pellets is a good effort for reducing grime and prolonging cleaning intervals.
Airgun barrels can not use DEEP rifling because it would destroy accuracy (deep marks on pellets), this is why rimfire & centerfire barrels DON'T work well with airgun projectiles, specially with the Diabolo shaped ones.
Accuracy in an airgun barrel is restored after passing 2-3 patches until they come out clean...Some people use plain dry patches, others use felt pellets and some other shooters use oil.solvents, etc.on one patch and then pass 2-3 dry ones...All methods are good and at this time accuracy is restored and the barrel is clean...
If there were any "lead fouling" as it happens in firearms, 2-3 dry patches would never remove a single layer of lead...We would have to use lead solvents and some kind of brushing...But then brushing would shorten the lives of our barrels...
Best regards,
AZ
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The problem with bismuth is that it's hard, brittle, and less dense than lead. Tungsten is very dense, but also very hard. It has an extremely high melting point and is difficult to machine. It would have to be jacketed or banded in something soft, and that would be expensive. Sintered tungsten powder encased in a plastic jacket might shoot well, but you'd need to find a plastic that wouldn't foul your barrel. Ungraded tungsten powder could pack more densely, but fine graded powder would pack more uniformly, and that's more expensive. (I've thought about this a lot... can you tell?) As for DU, I assume you're joking. It has all the downsides of tungsten plus the toxicity of lead.
I also wonder what kind of accuracy you could get with a smooth bore shooting steel APFSDS flechettes.
Sadly, the only non-toxic metals with the density and malleability of lead are also very expensive. Silver and gold would make great bullets!
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