Originally Posted by JonM
Its 1-7.7 best 3 shot group so far with only one range session half inch at 300yards. Krieger knows what they are doing. I talked with one of their reps told him what i wanted to do and just went with his suggestions. The fluting and bead blast was added.
Any chance we could get a look at ther research ? I have honestly never heard of a 1:7.7 twist. The problem lies not w 300 yd shooting but making the 5.56 an honest 800-1,000 yd cartridge. (below is copy/pasted from 223 Rem + 223 AI Cartridge Guide. )
The .223 Rem shoots a wide range of bullets very effectively, from 35gr flat-based varmint bullets, to ultra-long 90gr VLDs. However, you'll need the right twist rate for your choice of bullet. For max velocity and accuracy with the lightest bullets, a 1:14" twist may be ideal. More versatile is a 1:12" twist that will allow you to shoot the popular 60-64 grain match bullets. (However, a 1:9" twist is needed for the steel-core 62gr bullet used in the M855 military loads, because that bullet is as long as most 70-grainers.) For normal lead-core jacketed bullets, a 1:9" twist will let you shoot up to 73gr bullets. Since most .223 Rem shooters prefer bullets in the 50-73gr range, a good "do-it-all" solution is a 9-twist, unless you're a Highpower competitor.
For long-range match purposes, long, high-BC bullets are favored for their ability to buck the wind. You'll want at least a 1:8" twist to shoot the 77gr and 80gr MatchKings and 80gr Bergers. To shoot the new 90gr pills, a 1:6.5" is recommended, though a true 1:7" will work in most conditions.
Overall, what twist rate is best? For varminting we like a 12-twist. The slower twist will give you a bit more velocity, and minimize the risk of jacket failure at high rpms. For general use, an 8-twist barrel will let you shoot the excellent 77gr and 80gr Sierra MatchKings and nearly all varieties of non-tracer milsurp ammo. We'd only select a 1:7" or faster twist barrel if we had a need to shoot the 90gr VLDs.
Barrel Twist Rate 1:14" 1:12" 1:9" 1:8" 1:7" or 1:6.5"
Max Bullet Weight 55gr FB 65gr FB 73gr BT 80gr BT 90gr BT VLD