I didn't realize how much interest there is in hBN. It really does make a huge difference in barrel life, so I'll repost it and leave it here.
Answering email after email from a dozen different boards is getting really to be a chore, so here it is.
Both Dad and I consider this procedure to be important for Swiss rifles since barrels are hard to come by and very difficult to replace.
Doubly important for those of us who own zfk55's. All other barrels are definite candidates unless your bore is Electro Polished. Even negative 8 Micron won't penetrate that. Electro polished bores are not usual at all unless it's a custom ordered barrel with that process.
First, an old email response that will help a lot, and its an evolving explanation.
Ok. Even though the process isn't rocket science, this isn't exactly short. I'm posting all of the info I have from a 2 year period of successfully doing this. The main thrust of hBN is not to improve accuracy, but to prolong barrel life. When properly prep'd and slurry treated, your barrel can double and even triple it's expected accuracy life. These are excerpts from writings and emails to enquirers by my Father.
Every barrel in every rifle here but one has been treated. Not one projectile goes down range that isn't hBN inpact coated save those for one solitary Moly dedicated rifle.
Your bore is going to make a difference right out of the gate. Both Moly and hBN have specific applications. Lab Grade Moly is typically 99.8% pure with a 1 to 3 micron size. hBN (far more preferrable in most bores) is typically negative 5 micron or smaller.
First, hBN. The patent shows it as being most effective on a standard steel bore, and has no effect on a 17-4 S/S Electro Polished bore, this because the negative micron particles cannot ingrain themselves into the surface and create the required ceramic protective coating.
hBN is not susceptible to moisture and thus does not allow corrosion to affect the lands/grooves of the bore. This is a rather large advantage over Moly.
The process is simple. If you've ever fired a copper jacketed projectile in your rifle, use a water based copper removal specific such as Wipe Out. Whatever you use, make sure its water based and ammonia free. Once you've borescoped and found the bore to be completely copper free, if the bore is .30 caliber, roll a .270 (or whatever, but a bit smaller diameter than your bore) caliber clean swab in a mixture of 100% Denatured Alcohol and hBN. Use a small, sealable pill bottle, glass or plastic to mix and store the slurry. The ratio should replicate a slurry the consistency of whole milk. Run it back and forth through the bore. Within half an hour I fire an impact coated projectile through the bore and that's it. The bore is effectively ceramic coated.
Everyone has a methodology and most involve pill bottles in the tumbler suspended in media. I don't. I use 16oz (and larger) plastic jars with screw on lids, and not inside the tumbler in in the media. I made a secondary lid for the tumbler/vibrator on a CNC. Its 1/2" thick Sintra with a 1/4" deep channel cut into the bottom to fit over the inside and outside edge of the tumbler. A 5/16" hole is drilled in the dead center to acommodate the shaft and wing-nut. All four jars are spaced evenly around the shaft on top of the lid. The tumbler is empty.
Dillon Commercial
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Lyman Standard
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All four (or two) jars are filled to the 1/3rd mark with impact coated .177 steel bBBs. The BBs must be washed in Dawn with no additives or cleaned with a Sonic Vibrator and denatured alcohol. Add a nominal 1.5gr of hBN.
Place 50 .30 caliber (or whatever, untouched by human hands) clean projectiles in each jar, add a nominal .5gr of hBN and vibrate for three hours. The jars on top impact coat the projectiles easily 4 times harder and faster than in a pill bottle suspended inside the tumbler in media. Once the lids are screwed down tight, use a 1/2" wide strip of plastic tape around the area between the lid and the jar. Negative 5 micron hBN is so fine it can potentially find it's way through the threads.
Use a large slotted spoon, (slotted wide enough to allow the impact coating BBs to fall through, but not the projectile)s to remove the impact coated projectiles from the jars and tumble them in a Terrycloth towel.
We begin by stripping the chambers, throats and bore with Wipe Out. Its an ammonia free, water based bore cleaner that removes literally everything. Carbon, copper, any kind of fouling including Moly. We leave the Foam Type Wipe Out in the bore and throat for about two hours then dry swab everything. We do a follow-up inspection for any copper residue with a Hawekeye Borescope. A complete, 100% copper free bore is essential.
I wash the bullets in very hot, soapy water with Dawn. I use a bowl with a plastic strainer that just fits in it. Once washed, I thorougly rinse with hot water, not cold. From that point I handle the projectiles as little as possible and then only with disposable latex gloves. Assuming you've already treated the .177 steel BBs, you can put 50 to 75 .30 caliber or 100 smaller caliber bullets in each jar.
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(Update)
We've added to our method just a bit. We now place a thin layer of dense foam in the bottom of the Dillon. the jars are sealed where the top threads down onto the jar with plastic tape to keep any hBN from leaking out. We place the jars on their sides and pack them in with chunks of foam. We place enough foam on top of them so that when the vibrator lid is screwed down they're trapped tightly. This keeps everything horizontal and the bullets stay on the horizontal position. Works much better and you won't need a specialty lid for your Dillon. The attatched pics are of one of our smaller vibrators with two of the older jars we original used. We now use the new jars in the larger Dillon, but they do show how the jars are packed and kept horizontal.
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With hBN, heat is definitely good but not entirely necessary. We use heat in the form of a Halogen body shop lamp. Placement of the lamp is critical for the well-being of your tumbler. Too close and you'll soften the plastic. Vibrate them for 3 hours. Remove them with a slotted spoon and tumble them in a Terry towel a few times. They'll come out perfect. This horizontal impact coating with steel BBs in a vibrator with no media makes them hit hard and fast, and that's the secret to perfect coating. Even small tipped bullets come out perfectly with no damage to the plastic tips at all.
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This original system we developed works well too. The advantage is that you can add media in the tumbler/vibrator and clean cases while impact coating your projectiles. We still do this once in a while, so we often have both methods going at the same time.
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This is the original patent if you're inclined to read it all. Sometimes its not easy to find the pertinent parts in all of this dry reading, but its all there. We've made a study of it, and we're very successful doing it.
www.patentstorm.us/patents/7197986/description.html
(Note:)
If you don't have the foaming type Wipe Out for your bore, use the liquid Wipe Out with a nylon bristle brush, working up a heavy foam and let stand for a few hours.
Put the foam nozzle in from the breech and push down just once or twice. It expands tremendously. Wait till you see it appear at the muzzle, then you can plug the breech end with a fired case and a dry patch at the case mouth. Push it in tight.
Dry clean completley with patches or clean swabs.
Take a new .30 caliber cotton swab, or take your old ones and run them through the laundry or dishwasher. Dry completely.
Short switch back to square one:
You'll get your hBN in a container with a plastic, tape seal around the outside. Open it with extreme care and only long enough to fill a small, sealable pill bottle 1/3rd full. Re-seal the container immediately. Re-apply the exterior tape seal fully and tightly. Store at room temps in a secure place. Spill that container in a room in the house and your wife will be using a bat on you for weeks to come.
(No, I didn't, and my wife learned from mk,y nMother and uses porcelain Darning Eggs instead of bats!)
Screw the swab to the end of a cleaning rod just long enough to run the bore, open the hBN/Alcohol slurry pill bottle, roll the swab in the hBN/Alcohol slurry, (close the hBN bottle immediately) insert into the bore from the breech end if possible. If your rifle won't acommodate that, run it carefully from the muzzle end. Go all the way through and then work it gently back and forth while slowly withdrawing the swab.
The first impact coated projectile fired through the bore will do the ceramic coating for you, and that's it. You've done it. From that point on fire only impact coated projectiles through that rifle. Cleaning is done with dry patches, no chemicals at all.
For the chamber/throat area, use the right sized swab to fit into each and use Montana Extreme or a like carbon remover. Don't run any cleaning solvents down the bore.
If you feel the need to do that once in a while, cool...... but make sure you use the clean swab and do the hBN/Alcohol slurry process again. It only takes a few minutes. I unscrew the swab and keep it inside the slurry pill bottle so that it remains uncontaiminated.
To understand how it works, save me a bunch of typing and read the patent.
So how often do you clean an impact coated bore? 50 rounds? 100? 200? 300? 1,000? I don't know yet. No cleaning required so far, and if the patent is correct it will be a long time to come.
The Hawkeye Borescope always tells the glaring truth about your bore. After each shooting session I pass one dry patch down the bore, just once. So far in any and all of the bores thus treated.......... no necessity to clean at all. The most amazing has been the little .22 rifles.
