Bullet Smoothness

[Dave M.]

@HappyHellfire , check the surface roughness of your baseline factory bullets and make yours the same. Measure them with surface roughness meters which maybe available at your university. I’m guessing between 8 to 16 Ra.

Not sure what units you are talking but 8-16 micrometer Ra is considered extremely rough. I imagine your units are different. I assume you are talking in terms of micro-inches, in which case 8-16 would be a fairly smooth

 

[chop house]

Where is the popcorn, here we go again! Lol
Paul

 

[M-61]

That's why fighter jets have dimples like a gulf ball.

Lost me. Where are the dimples on fighters? Or basically any aircraft.
Maybe I’m not following you?

 

[HappyHellfire]

Pretty sure none of us possess this equipment at home and my work frowns on me using the Met Lab.

I have this new lathe and until sales grow I have excess capacity to play. I might get another paper out of it.

 

[Newhouse]

Not sure what units you are talking but 8-16 micrometer Ra is considered extremely rough. I imagine your units are different.

Average Roughness basics - Michigan Metrology

average roughness basics , roughness average, surface roughness measurement, surface texture parameters - Michigan Metrology

michmet.com

As far as the equipment, you can get a basic surface roughness comparator at amazon instead of the expensive equipment use in the labs or by companies with metrology department.

 

[Webster]

Look at golf ball design as well. The dimples make for less drag as the ball flies.

Sorry, Webster; didn't see the second page of replies.

At least I didn't get flamed on my comment.

 

[Chris Edmondson]

Industrial surface roughness comparators are seriously expensive, way above my pay grade.

I bought a used one of these old-school comparators on eBay for relative pocket change. There's an element of subjectivity using something like this but, once my NASA Space Shuttle contract concluded, I figured what the heck .

 

[Webster]

Lost me. Where are the dimples on fighters? Or basically any aircraft.
Maybe I’m not following you?

It was a joke. If dimples improved performance wouldn't the miltary put dimples on fighters and missiles. I'm sure they reason they don't is because they don't help performance at very high speeds. The origial poster said he spent years doing the math and shooting the bullets in a totaly unsuitable rifle for testing. He needs to buy a barrel with the proper twist and caliber to create real numbers. The years go by with no real shooting data.