This morning I spoke with Legacy Int. The importer for Howa rifles and asked what bullet weight they suggest for the .204 Ruger with a 1 in 12 twist. They said a 32 grain. Also, this is information that they received from Hornady.

So far in my shooting, this is true; the 32's are more accurate than 40's. Oh , the 40's shoot real good, about 3/4-1.25" groups with most loads, but the 32's go 3/8" to 3/4" with more than one load.

Yep - From Walt Berger @ Berger Bullets:

.204 CAL 30 GRAIN ID: 20-30Category: Bullets
Recommended Twist rate is 1/16 Ballistic Coefficient is 0.163 Flat base

.204 CAL 30 GRAIN MOLY ID: 20-30 MOLY Category: Bullets
Recommended Twist rate is 1/14 Ballistic Coefficient is 0.163Flat base

.204 CAL 35 GRAIN ID: 20-35 Category: Bullets
Recommended Twist rate is 1/14 Ballistic Coefficient is 0.191 Flat base

.204 CAL 35 GRAIN MOLY ID: 20-35 MOLY Category: Bullets
Recommended Twist rate is 1/14 Ballistic Coefficient is 0.191 Flat base

.204 CAL 40 GRAIN LTBID: 20-40 LTB Category: Bullets
Length Tolerant Bullet Recommended Twist rate is 1/12 Ballistic Coefficient is 0.239 Boat tail

.204 CAL 40 GRAIN LTB MOLY ID: 20-40 LTB MOLY Category: Bullets
Length Tolerant Bullet Recommended Twist rate is 1/12 Ballistic Coefficient is 0.239 Boat tail

.204 CAL 50 GRAIN LTBID: 20-50 LTB Category: Bullets
Recommended Twist rate is 1/9 Ballistic Coefficient is 0.296 Boat tail

.204 CAL 50 GRAIN LTB MOLYID: 20-50 LTB MOLY Category: Bullets
Category: Bullets Length Tolerant Bullet Recommended Twist rate is 1/9 Ballistic Coefficient is 0.296 Boat tail