Button nosed wadcutters

[Marty Robbins]

What purpose does the button nose on a wadcutter serve?

[Outpost75]

Deflects bow wave of subsonic projectile to reduce aerodynamic drag.

[stubshaft]

Deflects bow wave of subsonic projectile to reduce aerodynamic drag.

WOW, got it in one!

[M-Tecs]

http://www.lasc.us/Fryxell_Book_Chap..._Wadcutter.htm
That cute little vestigial nose left on these Type II wadcutters is intended to provide additional aerodynamic stability by breaking up the air-flow and starting the slipstream. Since these are virtually always subsonic bullets (not only sub-sonic, but below 0.85 Mach, or roughly 900 fps), the airstream is roughly conformal to the bullet's profile, with turbulent flow in the boundary layer at these velocities. There is no super-sonic "bow-wave". A flat face with a sharp shoulder (e.g. Ideal 358348) can induce substantial turbulence just aft of the shoulder. This is because the slipstream is unable to flow smoothly around a sharp 90 degree corner, so there are turbulent "eddies" formed just aft of this shoulder, which can destabilize the spinning wadcutter and lead to tumbling. By putting a small nose just forward of the flat face, the airflow is more gradually redirected as a result of the eddies formed along the sides of the nose, resulting in somewhat greater stability in flight, and therefore longer accurate range before the wadcutter starts to tumble.This "aerodynamic re-direction concept" was most pronounced in the Himmelwright wadcutters, and tapered off with subsequent designs. Since virtually all bullseye shooting is done inside of 50 yards, that's all the accurate range that's needed from a wadcutter target load, so the extended proboscis of the Himmelwright wadcutter really isn't necessary. Because of the complexity this proboscis adds to the seating/crimping step, it was simplified (or dropped altogether) in subsequent wadcutter designs.

[gwpercle]

Deflects bow wave of subsonic projectile to reduce aerodynamic drag.

What Outpost75 says ... and it Looks Good , like the fins on a 57 Chevy !
Gary

[mdi]

Deflects bow wave of subsonic projectile to reduce aerodynamic drag.

Yep! Makes sense...

[MT Gianni]

In his classic treatis, Cast Bullets, Col. Harrison found that they are more accurate than flat nose wc's for the reason Outpost stated. He also found that lubing only one groove of a multi grooved bullet was more accurate.

[Marty Robbins]

Thank you Outpost75 & M-Tecs for the information!

[Martin Luber]

Any idea why one lube groove would be beneficial?

[Mk42gunner]

Less likely to throw off the balance when the soft lube is thrown off in flight?

Just a guess.

Robert

[Green Frog]

OK! I'd been wondering all this time about the "button plus" or "SWC minus" design of the 323445 for the 32 S&W L and H&R. I guess if a little button is kinda good, a little more button is "kinda gooder".

Froggie

[david s]

Just cast some 32 wadcutters last Saturday including one with the cute little button nose albeit hollow pointed.