Quote Originally Posted by enfield2band View Post
The bullet has to match the rifling twist. The faster the twist the longer the bullet has to be.
Quote Originally Posted by enfield2band View Post
I think that is a generalisation. You don't buy the bullets and match the rifle. You use the bullets that are most suited to the gun. It likes saying get a shotgun with a 3 inch chamber and you can shoot anything through it from 2" to 3".
On that basis why not just buy a 1:6 twist and you can shoot anything through it.
I'm sorry. Yes, you buy the bullets that will work in your barrel, but your first post seemed to imply that the bullet length is dictated by the twist, not limited by it - it read as a fast twist needed a longer bullet when actually a fast twist can take a longer bullet, just doesn't need to be a longer bullet.

My .223" was 1:8 I could get clover leaf groups at 100 yards, (prone unrested with a scope) with 68 gr Sierra Match Kings and 68gr Hornady.
I tried the military bullet and it was on target but would have need developing to be accurate, maybe!
Military bullets (FMJs) are inherently less stable than match bullets like the SMK. A small error in finishing the jacket point on a HP bullet is a much smaller turning moment than the same error on an FMJ which is finished at the bullet base. This leads to slightly greater instability in the FMJ and which is why SMKs cost double or more than a similar military FMJ.

I have found that some particular faster .223 loads give me a very similar group when I test them at 100yds as at 200yds. I was told this could be because the bullet needs time to settle down into its flight and being fast it may travel more than 100yds before it achieves this. I don't know how true the explanation is but it still works out on paper.