lube groove depth/width

There are a number of things that determine the depth and width of lube grooves. Mostly it either proformace at the range or just someones personal “feeling” that determines it.

When I design bullets, I do it based on 30 years of studying sucessful, target designs and in that, I’ve found that depth per side of the grooves can run between 3 and 5% of the bullets diameter and the width of the bands will be from 1 to 1 (ie .050 groove .050 band) to 2.5 to 1.  By a ratio of 3 to one, leading will ocure on long strings or hot days.

All the above, applys to PB bullets, I’ve also shot GC bullets and you can get away with less groove and more band using a GC.

Frank

I’m not much of a pistol shooter. My experiance with them is 45 Colt and 357 Mag & Max. In thoughs calibers, I’ve been interested in longer range loadings. I’ve used short bore riding cast bullets in them, including the 35875 and the 358315 (both cast 208 gr) in the 357’s. 1″ to 1 1/4″ is good to me at 25 yards for pistols.

In pistols, it’s harder to see a change in accuracy and as long as they don’t lead, you can most likely find that accuracy with most any bullet.

The 358627’s long lube groove would be good for preventing leading but, will weaken the rear of the bullet for HV loads on exiting the muzzle.

Frank