Stupid Question?

[Dave_W]

Hi All,

I was researching a recipe for a 40 S&W and I had a question.

If a 155gr bullet needs 8gr of powder, why does a heavier bullet (180gr) use less powder (6.7)?

David

 

[doobie]

Hi All,

I was researching a recipe for a 40 S&W and I had a question.

If a 155gr bullet needs 8gr of powder, why does a heavier bullet (180gr) use less powder (6.7)?

David

Different pressures would be my first guess. But you didn't specify if it was the SAME powder as well as the muzzle velocity

 

[drgrant]

Because a heavier bullet will (generally) build up more pressure during
firing, so the charge must be less to keep the load within acceptable pressure limits.

-Mike

 

[45 acp]

Because a heavier bullet will (generally) build up more pressure during
firing, so the charge must be less to keep the load within acceptable pressure limits.

-Mike

True also the bullet itself is longer reducing case capacity generating more pressure.