To find bullets that will work OK it is best to find bullets with a Gyroscopic Spin factor (Sg) between 1.4 (with enough spin that the bullet will not tumble at some further distance) and 2.0 (starting to overspin and may eventually affect accuracy).

Sg for BACO 38 caliber bullets in a 1:16 twist barrel:

1.91   Money 300 grain
1.62   Money 325 grain
1.68   Tapered Creedmore 345 grains
1.32   Elliptical 360 grains
1.32   Money 360 grains
1.34   Elliptical Mini Grease Groove 365 grains

To use the longer heavier .38 caliber bullets you need a tighter twist of at least 1:14 and preferably 1:12 twist.

Once you have the appropriate gyroscopic spin then you need to find the bullet nose that provides the best point of balance (dynamic stability) which depends on distances the bullet is travelling (time in air, nose deflection, and drag characteristics).


For short range 200 yards select a Spitzer nose or for hunting purposes a flat nose.

For mid-range shooting (500 yards) more rounded noses have better dynamic stability such as the traditional Government nose, Postel, Snover or Creedmore.

To reduce drag and nose deflection a pointier round nose of the Money or Elliptical has better dynamic stability for long distances (1,000 yards) however may require increased velocities to do so.

And of course all of this is dependent on tuning your spin rate based on the velocities you fire the bullet or increasing overspin to compensate for drag over long distances.

When selecting a bullet it is best to pick the longest and heaviest bullet; that the twist of your rifle barrel will handle, due to the improved Kinetic Energy and Ballistics Coefficient of these bullets.

My 1-16 twist Shiloh 38-55 really came together with a 285 gr. Accurate Bullet Mold  cast 20-1. The 335 Lyman Postel shot real well for Rams using 16-1 lead. Thats the heaviest I went with this gun. Worked for me.

Thanks John !