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My HBN experience and process
- Thread starter Calvin45
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Calvin45
Well-Known Member
Been enjoying the reading my thread has created.
Let the record reflect: I am not a materials scientist nor a ballistics expert nor an analyst. I am merely what some have lovingly (I think) called "an intellectual hillbilly"
I do not know nor claim to know the exact nature of all that goes on in the bore. I do know what i have experienced and will not deny what my eyes have seen. And I do think I have a pretty good grasp of the "why" and "how" behind it's effect. But I may not. What I do know is the effect itself. It's real.
I've gone through a lot of trial and error and experimentation and wasted time and components along the way. Regret nothing. This thread was merely to share my findings and the process I've come to find works best for me.
But I'm happy to say I've learned more than a few new things and certainly have a few new questions coming away from this conversation.
I wanna thank y'all for being civil even in disagreement thus far. There's been a lack of that on this forum lately in some threads I'm sad to say.
Let the record reflect: I am not a materials scientist nor a ballistics expert nor an analyst. I am merely what some have lovingly (I think) called "an intellectual hillbilly"
I do not know nor claim to know the exact nature of all that goes on in the bore. I do know what i have experienced and will not deny what my eyes have seen. And I do think I have a pretty good grasp of the "why" and "how" behind it's effect. But I may not. What I do know is the effect itself. It's real.
I've gone through a lot of trial and error and experimentation and wasted time and components along the way. Regret nothing. This thread was merely to share my findings and the process I've come to find works best for me.
But I'm happy to say I've learned more than a few new things and certainly have a few new questions coming away from this conversation.
I wanna thank y'all for being civil even in disagreement thus far. There's been a lack of that on this forum lately in some threads I'm sad to say.
Calvin45
Well-Known Member
Agree. "Friction". "Drag". Not exactly the same but very much a part of why hbn and other friction reducing coatings affect interior ballistics is the concept of "engraving pressure". There is no point during the firing of a cartridge I don't think where the pressure is gonna spike as hard, high, and abruptly as when that bullet is first forced into the rifling (only thing I can think of might be if you used a ridiculously strong crimp on a long necked case with a high bearing surface bullet, maybe glued it in there too
- or cold weld, whatever that is 
- the initial release from the case might be pretty dang high too)Whether they're right or not, it is of note that Winchester/Nosler combined technology lubalox bullets are overtly advertised as "reducing engraving pressure" with that layer of black copper oxide. And I do think that's why hbn treated bullets, ESPECIALLY those bullets known for pressuring up fast like the original ungrooved Barnes x and the pure copper jacketed scirocco 2, exhibit a lot less sensitivity to seating depth than naked bullets in my real experience. That initial pressure spike curve is made gentler I think. No proof. Just what makes sense to me and seems to jive with observed effects.
I am not a match shooter or competitor or elr sniper or anything. I've heard those types say that they didn't find hbn imparted any benefit worth the trouble and I believe them wholeheartedly. I also don't think match type bullets stand to benefit from this treatment as much as stout jacketed long bearing surface type hunting bullets but again, just my opinion. I also don't see it being nearly as beneficial in moderate case to bore ratio cartridges (again, the type competitors typically use) as it truly has shown itself to be for me in more overbore cartridges. It makes a number of real notable differences, all for the better, for me in my .243, .257 wby, and .300 win mag. I don't mess with it in rounds like .308, 8mm Mauser, and .358 Norma mag. Just don't see much point there.
To some extent they are but they are also different. I know drag goes up exponentially to speed but I don't think friction does.
The SR 71 Blackbird grows 10" from friction at top speed but I believe the temperature increase is linear not exponential.
Is it excepted that uncoated bullets have more fps and pressure than coated?
The uncoated have more drag and friction but have more speed? More heat from friction but more pressure from drag.
Calvin45
Well-Known Member
I don't think drag has anything to do with bullet-to-bore contact but do see what you mean about the difference - and in external ballistics I suppose you're right! drag isn't just the aerodynamic friction from the individual molecules of our atmosphere when the bullet has to push through them; if I'm not mistaken it's to do with the wall of resistance in front and the vacuum created behind the bullet, not just a matter of the gas that actually touches the bullet itself.
I was referring to bullet to bore contact. Metal to metal has drag or the bullet would just fall through the bore lol.
Take a dry patch on a jag and how much force does it take to overcome the drag? Now oil the patch and how much force does it take to overcome the drag?
I know the friction is reduced but is the dry patch much hotter than the oily one ?
Friction is the term used to describe the force required to move two solid objects in contact with each other. The force required to move a solid object in contact with a second solid object, is determined and quantified by, a "Coefficient of Friction". Materials scientists have generated Coefficients of Friction for just about any and all solid materials present on on planet earth.
To my knowledge, Coefficients of Friction only apply to solid objects/materials. The Coefficient isn't used to quantify friction/drag in fluids (either liquid or gaseous fluids). The SR71 friction losses due to fast flight through the atmosphere (a fluid) is another story. Altogether different than analyzing friction between a bullet and a barrel. That SR71 analogy has application to friction losses acting on a bullet during flight through air, after the bullet has left the bore. Basically zero application to a bullet traveling down a barrel.
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MagnumManiac
Well-Known Member
Drag and friction, although not in the same medium, are not a correlation of each other.
Bore friction is not the same as air drag, nor are the parameters that govern each. HBN has nothing to do with drag in the air…
Cheers.
Bore friction is not the same as air drag, nor are the parameters that govern each. HBN has nothing to do with drag in the air…
Cheers.
Ok my analogies are not coming through very well. Metal to metal contact should be friction but reduce the friction and you reduce the pressure to overcome the friction or the drag in my way of thinking.
Reducing pressure is going to reduce fps.
Reducing pressure is going to reduce fps.
@Calvin45 or anyone else with experience with HBN
I know its old, but resurrecting it. I am considering embarking in HBN coating. Read Calvin's great write up, thank you sir, and I watch a couple of videos.
I don't have one of those great tunblers, I have a Lortone two drum tumbler like the picture below. If I dedicate one of the drums for HBN, will these work? Thanks in advance
I know its old, but resurrecting it. I am considering embarking in HBN coating. Read Calvin's great write up, thank you sir, and I watch a couple of videos.
I don't have one of those great tunblers, I have a Lortone two drum tumbler like the picture below. If I dedicate one of the drums for HBN, will these work? Thanks in advance
Attachments
Calvin45
Well-Known Member
For sure that'll work fine, it's a rotary type, definitely better than vibratory. And remember….LESS IS MORE! I can't stress enough that my number one rookie mistake was putting too much of the hbn powder in with the bullets. Ya need just a smidge haha
Thank you! Appreciate your taking the time to respond!
