Available EABCO Twist Rates

The optimum rate of twist for a barrel depends on the particular cartridge, caliber, and bullet weight you want to use. Here are the twists we offer:

.17 Cal - 1:9
.22 RF Cal - 1:16
.22 CF Cal - 1:7, 1:9, 1:12, 1:14
6mm/.243 - 1:8, 1:10, 1:12
6.5mm/.264 - 1:8
.270 Cal - 1:10
7mm/.284 - 1:9
30 Cal - 1:8, 1:10, 1:12
338 Cal - 1:10

How to Choose a Twist Rate

Some of our barrels are offered in multiple twist rates, or you can special order your choice of rifling twist rate when you order one of our Custom Encore or Contender barrels.

We have standards we recommend for various chamberings so you don’t have to figure this out yourself. But if you’d like to know some guidelines and reasons, here they are:

17 Caliber: Use 1:9 for centerfires.
22 CF (Centerfire): 1:7 is only for the heaviest bullets. 1:12 shoots 40-50gr bullets accurately in 223, and up to 55gr in 22-250. Use 1:14 only for the lightest bullets.
6mm/.243: use 1:8 for 90-100gr bullets. 1:10 for 75-85gr, and 1:12 for lightest bullets (ie. 58gr in 6PPC).
30 Cal: the 1:10 twist is the best all-around sporting/hunting. It stabilizes anything up to 180 grains which is pretty much all of the hunting ammunition at the local sporting goods store. 150-160gr would be optimum. We DO build a few 30’s in 1:8 twist for those who shoot the heaviest bullets.. 180gr up to 220gr and heavier. 1:12 Twist is the slowest and is primarily for competition and benchrest shooters who shoot the 155gr match bullets. This twist is best for the lightest bullets up to a max of 155gr.

The rule of thumb with twist ratest is this: It is better to err on the side of too fast rather than too slow. Too fast and the bullet still usually shoots fine, but too slow and the bullet will fly sideways and “key hole” in the target.

Slow 1:12 twist is preferred by competitors who are trying to minimize the smallest imbalances in their bullets. Their goal is to spin the bullet only as fast as it takes to stabilize it and no faster. They are sometimes on the ragged edge which is not the best place to be in a hunting/sporting situation.
Choice of twist rate is only available when you order a custom barrel by E. Arthur Brown Company. Most ‘on the shelf’ barrels are a standard twist.