You all need to give CFJ a listen. This method is called OCW, and he can explain it the best I have heard. It is pure applied science and understanding of materials. I am a believer and student of this teaching.

Dave you eluded to it with out knowing when you talk about barrel harmonics. The accuracy nodes show up when the refraction timing is near the chamber and the bore is least effected.

Now back to my OP. Convince me what lenght barrel to order. I am at 26" light Palma at the moment, with no threading. :)