@jarmstrong It may seem that way if you only read the title, but if you review my initial post you'll see there were several questions posed. I asked the original questions and questioned a response or two. And I've read parts of threads on the GTA including posts by Knifemaker. My goal was to gain a better understanding. Thanks to all who responded.
It's not my assumption it's just the way it works. I learned this by paying attention to what other people were telling me. For some reason it doesn't seem hard to understand to me so perhaps my explanation was vague? Here is a diagram with an exaggeration of the effect that might help you visualize it more clearly.
@MrP Maybe it wasn't your assumption, but I was simply using your words to try to better understand a concept. Nothing wrong with admitting that you're assuming when you don't understand. At least you made that clear so you were not misleading anyone. My goal was to gain a better understanding. Several of you were helpful there so thank you for that. The above illustration is really helpful.
@MrP I didn't take it that way. I read it as if you were explaining the concept the way that it made sense to you, but you didn't feel like you could explain the process precisely in detail. Consequently, you provided illustrations that supported your idea. It was honest and helpful to me. I think the one thing that kind of ties it all together is the quote below. I was thinking that the uneven surface produced by knurling, more specifically the waffle type of pattern, would create a higher probability for air escaping around the projectile resulting in a loss of velocity. How much velocity? I have no idea, so I thought I'd ask. Personally I don't understand everything that occurs in the barrel before the projectile exits the muzzle after pressing the trigger. I only know what I can see and I try to make improvements based upon my understand of that. I'm still learning so I ask questions.
@MrP It looks like something that may be interesting to play with. I prefer to spend more time shooting and hunting than making projectiles. That thing looks slow, but it's probably faster than some of the DIY methods I've seen. If the slugs produce the result(s) one seeks, then I guess that's where the true value lies. Now your idea about the Huben platform is one of the first things I thought of when I saw that device. The transition from the mag to the barrel had me wondering about the effect(s) of that transition. Mainly because I recall reading some things that suggest that the chambers of the mag are larger than that of the barrel (I was reading about the K1 and I'm not sure if this is the case in all K1s). I was thinking if the knurling was damaged some sort of way that air may escape around the slug throwing off its stability in flight. But I don't know enough to make good sense out of the thought.
@sb327 The sealing aspect was the last part the I was able to understand and the focus in the later posts in this thread because the earlier answers were not addressing that question.
Same here I always thought knurling made a series of staggered diamond impressions and so knurling grooves wasn’t obvious. But of course it makes perfect sense when you think about it.
VK now has .223 slugs he offers in both 28.5gr, and 32.8gr. I'll be testing the 32.8gr out of the Huben GK1 and K1 this week since these are brand new
