Can some body explain to me why you would want a 1-9" twist in a medium range varmint rifle like the 223.
1. For me, the reason is that I want to make subsonic .223 loads and supersonic loads using heavier bullets. I want to be able to nail a prairie dog at 100 yards without having to put in earplugs first. This means 22 LR noise level.
2. Subsonic/slightly supersonic .223 loads are flatter shooting (Higher BC bullet) and more accurate than a 22 long rifle.
3. The heavier .223 loads also tend to be quieter by a few DB because there is less muzzle blast. (This point is subjective to some people.)
4. Heavier bullets tend to do less damage to hide than light fast bullets that fragment. If one saves the fur, this is important.
5. Military surplus 62 grain .223 needs a 1-10 twist at least. (This is a big reason for 1-9 twist)
6. You can load heavy bullets to 22 Hornet noise levels for pest control and switch instantly to the high power stuff if you need the extra range.
A 1-9 twist gives (.223) the ability to do everything between a .22 Long rifle and gets within a few hundred FPS of low end 22-250 loads. (Though high end 22-250 loads leave the .223 gasping for breath.)
I used to own a Howa 1500 .223 rifle (I sold it) with 1-12" twist. I tried to load subsonic .223 using cheap 55 grain bullets. I was able to get the loads down to about 1500 FPS or so before the bullets would not stabilize and tumble after they left the barrel. Yes I could have gone to lighter bullets, but then the BC and energy of the bullet falls off close to the 22 Long rifle, defeating the whole point of what I was trying to do. A 1-9 twist will enable me to load the 55 grain bullets to the speed of sound, be flatter shooting, and have more retained energy than a 22 LR with the option of having full power .223 by just popping in a different shell.
Why lug around a 22 Long rifle, a 22 Hornet and a .223 when you can carry a .223 and different ammo loads. I have different 22-250 loads and mark the case head with a different colored sharpie. I would do the same with different .223 loads.