Why not use the heavier bullets in rifling with 1/10" in .243 bore? The .243 Win is generally bored with 1/10" as standard and mine (Ruger RSI) shoots everything from 85 gr to the 105 Speers extremely well. In fact, it shoots the 100 gr much better than the lighter bullets, 3/4 minute of angle at 100 meters. There is no reason to think the 6mm AI would not do just as good with these bullets. My standard 6mm (Browning 78) shoots 100 and 105 bullets to 1/2 minute angle at 100 meters. I admit the twist is 1/9", I think. Also, the 26" free floated octogon barrel might be the difference in accuracy and not the twist rate.daddyof4 said:I have one and would use it for deer. I have a 1/10 twist so I can't really use the larger bullets. You can try Reloader 22 and Dupont 4350. Mine likes the 100sbt's and the Sierra 85 gr hpbt
Try the 100 gr bullets by different makers and vary powders and loading. I use slower burning powders in the .243 and find the accuracy improves over the slower burning ones. Admittedly these loads are in the maximum pressure range. My load (not a recommendation) for 100 gr RN Hornady, 100 gr Partition, and 100 gr Sierra Gameking bullets is 42 grains of IMR 4350 with CCI 200 or Federal 210 primers in R-P brass. Also to prevent brass stretching, I neck size after the first firing. This improves accuracy too.daddyof4 said:mine with the 1/10 twist looked like a pattern with 105 speers and the 107 matchkings weren't much better. Now this might only be in my rifle but that is all I can comment on with any degree of accuracy.