25WSM
Well-Known Member
Mram I have a solution to your problem. Pretend it's a 308win and now just like that it's fast.
Shep
Shep
Polishing is the opposite of what you want for velocity, when the Cheytac was being prototyped my father in law was lapping the barrels with 80 grit to get the velocity. Most barrels are in the 220 is range average.Lapping might be the wrong term. The goal was to polish the barrel to help remove some friction to add speed. Again, just a test. It still shoots very well, so I'll do more testing on another rifle. Thanks for the info guys.
This always threw me off. Guys will say a polished chamber is bad cause the case has nothing to grab, but then argue the polished surface of a bore increases drag....always got me thinking. Airplanes want a Polished finish for less drag. I'm probably missing something.Polishing is the opposite of what you want for velocity, when the Cheytac was being prototyped my father in law was lapping the barrels with 80 grit to get the velocity. Most barrels are in the 220 is range average.
I wouldn't expect a 210 to be that much faster, the 215 guys will get more velocity with a shorter bearing surface!
Below the waterline on boats there is some evidence that a less than smooth finish results in air being captured by that surface roughness, which creates a boundary layer that is easier to shear than water. Less drag on the hull = faster boat.Sometimes too smooth isn't good. This might be the case with bores and copper fouling. Doesn't carbon act as a lubricant? If the surface was so smooth that there was no place for any carbon to embed, I would think fouling could be worse.
I was going to take a picture of my JB containers to show the difference of the two but you beat me to itView attachment 192392
Two different animals. The red is a fine polish. The blur cleaning compound wouldn't do much in the way of lapping IMO.