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Post by rossman40 on Aug 16, 2012 9:25:29 GMT -5
I have been asked to assist in another research project concerning bullet lube/coatings with a group of benchrest guys. This started by people asking me how to duplicate the Lubelox coating. Basically what will be done is a copper oxide coating which is what the black Lubelox coating is used by Winchester and Nosler. It is much like black oxide or bluing (or even anodizing), just a chemical dip process that converts the outer layer of copper to copper oxide. This makes a porous surface (reducing friction in our case) and is used to form a bonding surface when coating copper with polymers. If you were to look at the surface with a high power microscope it would look almost like the surface of a green Scotch pad. The copper oxide left in the barrel is easily removed or just burns off.
I brought up then applying a high end bullet lube. While some guys have had luck with moly coated bullets the latest and greatest lube is Hexagonal Boron Nitride (HBN). HBN has all the benefits of moly but none of the drawbacks like "seasoning" the barrel, the build up of moly in the barrel and the possible reactions with other chemicals to produce corrosive compounds.
Most of the shooting will be done starting in the fall and then run into next spring. Hopefully one of the barrels in the test group will be a SS with the hot new nitride coatings that ups surface hardness to like 70rc and doubles the life (accuracy wise) expectancy of the barrel even with some of the "barrel burner" cartridges.
How this may work into sabotless SMLing maybe interesting. One thing I have not heard about is copper fouling/build up shooting sabotless. What is neat is the copper oxide coating can be done after resizing/forming with no dimensional change.
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Post by rangeball on Aug 16, 2012 9:53:12 GMT -5
Sounds promising, and interesting. Please keep us posted
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Post by 10ga on Aug 16, 2012 21:06:50 GMT -5
AAHHhhhh, more stuff to buy and learn how to use. I'm just saving for a build for next year. Gotta get ready for the hunting season now. 2 SML newbies to break in and a new to me rifle to get ready. So little time, so many deer. 10
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Post by Dave W on Aug 16, 2012 21:43:07 GMT -5
I find copper fouling very little of an issue with sabotless, provided I shoot dirty. I have fired as many as 50 shots with no loading issues. When I was swabbing between shots you could notice a difference in seating pressure and there was more copper wash on the cleaning patches when I cleaned the bore.
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Post by lwh723 on Aug 16, 2012 21:45:50 GMT -5
I'm not sure lubed bullets will be a winner for MZ's. I would theorize that the slicker bullet won't build pressure as quickly which would delay obturation. But it does sound like an interesting project.
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Post by cuda on Aug 17, 2012 8:32:01 GMT -5
Some say to lube the wool wad before loading to help with some tight fitting bullets.
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Post by edwardamason on Aug 17, 2012 15:33:23 GMT -5
IOne thing I have not heard about is copper fouling/build up shooting sabotless. . I suspect the reason for that is the projectiles that you guys are shooting. Their given gilding metal used in the jackets can make a big difference. In the Case of the Barnes X bullets it comes down to the quality of the copper they use. The soup can projectiles probably limit the amount of copper fouling you guys are seeing. Long rifle bullets tend to copper foul quicker than shorter, fat flat projectiles. The quality of the barrels you guy are using limits the copper fouling to a degree. A rough bore is naturally going to foul more than a proper hand lapped custom barrel. Then there is the flip side. A bore that is too smooth can copper foul as quick as a rough barrel. That is one reason I do not suggest hand lapping a custom barrel. I generally trust the manufactures that make these fine barrels do their own lapping because for the most part t they understand the molecular structure of the barrels better than any end user. Everyone that has been around this game for very long and studied it knows that longer barrels and faster twists generally copper foul more quickly. Why some barrels accumulate copper fouling faster than others is not really a large mystery. It really comes down to a few key things. The quality of the barrel, the quality of the components and the end users care and maintenance of the barrel. The end user and the learning curve is probably another good reason you are not seeing more copper fouling with the SML that you are building. The end users tend to be a bit more experienced in cleaning and break in procedures. Your average Joe with a stock Savage probably does not have the understanding of these principles and will ignore all the advice that is out there on break in and cleaning procedures.
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Post by rossman40 on Aug 18, 2012 17:28:35 GMT -5
I think as we start to up the velocities with hot projects like the .416 the copper oxide may help to add just a slight amount of slickness to lower chamber pressures. If the pressures are too high maybe step up to the HBN as a way to lower pressures and still keep the velocities up. We just never have gotten real good data/answers on the differences on interior ballistics between CF and ML. There was one guy that was putting moly on sabots. Anybody remember that?
Would a un-polished copper oxide coating improve the grip of a saboted bullet on a sabot?
Then again shooting black bullets would be kinda cool. Not only would it be easy to see the rifling/groove contact/wear but you could always tell everybody they were special "black talons" for a 10ML...
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Post by muznut on Sept 7, 2012 13:22:18 GMT -5
I was hoping the copper oxide would increase the bullet diameter a little. It might be a simple way of knurling, if you get it down right.
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Post by Deleted on Sept 8, 2012 14:56:49 GMT -5
I shot some 250 SST's sabotless coated in Boron Nitride last week in my Pacnor. I did not wipe them down, just left the white powder on except for what got wiped off on my fingers loading. They did go down the bore nicely. They were some slippery suckers! I never looked into the price but I have the number for a shop that sells it. The benchrester that coated my bullets was not sure what he paid.
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Post by dannoboone on Sept 8, 2012 20:20:55 GMT -5
I shot some 250 SST's sabotless coated in Boron Nitride last week in my Pacnor. They did go down the bore nicely. They were some slippery suckers! That's all interesting, but how did they group?? Were the groups smaller, the same, or larger than those without Boron Nitride?
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Post by Richard on Sept 10, 2012 19:36:45 GMT -5
It is definitely nice when you put a post like that on the forum to follow up with the results I felt the same way as Danno! Richard
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Post by Deleted on Sept 10, 2012 20:21:35 GMT -5
Group was just over an inch vertical string with 58gr 4198. Realized I had a loose scope rings a few days later so the target was not posted. It was sent to Danno though. 5 shot group uncoated. Bore was squeeky clean prior to this group. Coated Didn't realize I used H for one and IMR for other till just now.
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Post by rossman40 on Sept 17, 2012 8:14:05 GMT -5
It's weird how the coated group had almost zero horizontal dispersion, that's good shooting. You do not have chrony data to go along with it do you?
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Post by Deleted on Sept 17, 2012 8:35:41 GMT -5
No chrony data
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Post by rossman40 on Sept 17, 2012 17:29:02 GMT -5
The way it walked up the target I was wondering if the bullets got faster as if the barrel started to "clean-up" or a layer of lube remained behind.
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Post by Deleted on Sept 17, 2012 18:21:56 GMT -5
The next time I run into the gentleman at the range who has the powder I will have him do some bullets again for me. He said he wipes it off his rifle bullets before loading. Apparently the powder comes in different grades as he told me to get the finest grade possible if i bought some. He prefers this over moly. It is some slippery stuff. The first bullet slipped right out of my hand onto the concrete. The group was vertical but they were right in line. Probably a few grains more would tighten it back up?
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