Maybe the bullets aren't spinning fast enough to stabilize themselves, or the rifling isn't gripping properly, there are a number of reason causing keyholes.

OK, then what may be happening is that as the bullet exits the case and enters the rifling, the bullet being made of soft lead, is being deformed particularly at the base. As any rifle shooter can tell you the base of a bullet is the steering end, so the deformed base causes the bullet to tumble. A jacketed bullet will better maintain it's flat base, and therefore not tumble. ?quien sabe?

Try some jacketed bullets and see if you experience the keyhole effect!

Hi,

Here I can readily agree with you! Amen!

I purchased some seemingly well designed swaged bullets that had bases that looked like they had been dragged by a school bus down a gravel road.

The result was horrible consistency, even though the bullets themselves were good as to weight variance.

Always carefully examine the bases when you are buying cast, swaged or other soft bullets.


Sieger