DIMPLES

[LongRanger]

More specifically, Berger 105 VLD dimples.

Have noticed that my home-moly'd 105 Bergers look distinctly different from home-moly'd 107 SMK's tumbled the same amount of time. While a slight pass over the SMK's to remove loose moly dust makes them shine like the Lone Ranger's silver bullets, the same treatment to the Bergers left them still dull and dirty looking. So, thinking the Bergers just had a stubborn residue on them, I tried polishing it off by tumbling them for a while in cob media.....no notable difference. And, I could not get them to polish-up even with vigorous rubbing using either a cloth or paper towel.

When I looked at the moly'd Bergers under magnification, the reason became apparent. Their entire surface was dimpled like a golf ball.

Hummm! We know that golf balls fly further and truer with a dimpled surface. Maybe this is why the Bergers are shooting inside the SMK's from my rifle? Maybe this is why the Bergers at the same starting velocity are impacting higher at 1000y than the SMK's from my rifle?

If anybody from Berger reads this.....Don't change copper hardness formula or nuttin,esp prices)!

 

[chuckw2]

Very interesting Loneranger, can you post a pic?

Chuck

 

[LongRanger]

Ha ha ha.

Too late for pix, Chuck. I shot all of them while you and Larry were scoring for me Saturday and Sunday. Have youse two guys as witnesses that they worked purty good in my clapped out barrel, don't I?

Regards,
Frank
Your ORSA shooting position 15 buddy.

 

[brickeyee]

Dimpling to force the boundary layer into turbulent flow sooner,like a golf ball) only works at sub-sonic speeds and for relatively round objects with high base drag.
At supersonic speeds there is actually rather little air flow over the surface of the object.

 

[chuckw2]

Frank,
Didn't know that was you. I will send you information on our next 600 x 3 at RBGC.

Chuck

 

[Hipshot]

I have moly'd both Berger and Sierra but quit using the corncob method of cleaning the surface. I now have a shallow tray where I pour 90+% isopropyl alcohol and dump the bullets in there to soak while I 'swish and dish' the bullets. I then take out the bullets,after about 3 minutes) and put them on a clean towel to fully dry, then I coat them. My results improved immensely using that procedure. I reclaim the alcohol and use it again, having to add some to make up for the losses due to evaporation and what's left on the bullets.

 

[LongRanger]

Dimpling to force the boundary layer into turbulent flow sooner,like a golf ball) only works at sub-sonic speeds and for relatively round objects with high base drag.
At supersonic speeds there is actually rather little air flow over the surface of the object.

"At supersonic speeds there is actually rather little air flow over the surface of the object."


Interesting. Could you explain more fully? Until now I've been pretty comfy believing that air over my wings at any speed keeps me airborne.