Slower twists and less grooves should scientifically allow less retriction & less friction in bullet travel?

what advantage does say a 5 or 6 groove offer over a 3 or 4 groove?
More surface area bite due to the extra rifling maybe means more uneccesary surface contact/friction and just more corners to clean?

Trax,

Usually the number of grooves will not affect pressure because the barrels are made to a minimum bore area standard. As you increase the number of grooves the width of the grooves increase (rifling widht decreases) to maintaine the bore area.

The rate of twist will affect pressure somewhat but very minimal.

Headache

Ok, can you tell me about the relationship between twist & velocity?

Say between an 1:8 vs 1:12, can we expect some effect on vel. worth noting?

Trax,

I do not have any information on twist rate affecting velocity. I would think the faster twist would affect the velocity but also very minimal.

I would select the twist rate for the heaviest bullet I expect to use and whatever it is it is.

Headache

Trax,
Listen to what Headache said. Also from your former thread, remember Alan Warner saying you will find more velocity difference at times from like barrels. I personally use the slowest twist that I can get by with for the bullet and allow for low temp.
Butch