Have any fence sitters got anything to say? Were you convinced one way or the other?
You stated that you yourself is "neutral", therefore you're on the fence as well. What did this thread do for you and what do you have to say about it ?
All this thread did was make me shake my head. Like any cartridge, the 6.5 CM has its supporters and detractors. But as so often happens on these threads, and other posts found on the Internets, it spun away quickly from the original post.
"The 260 has 2-3 grains more capacity and the 6.5x55 around five but I see loads for the Creedmoor that are faster than either. Is this due to the mythical cartridge efficiency or over optimistic reloading? According to JBs one quarter rule the 260 & 6.5x55 should get at least 30 to 60 fps more than the Creedmoor."
To answer the OP's question, the 6.5CM is loaded to higher pressures than the other two cartridges. The slightly higher volume of the Swede is negated by its lower operating pressure. 7977 PSI lower.
260 Rem - 60191 PSI - PMax - case volume - 53.5 gr. 6.5x55mm - 55114 PSI - PMax - case volume - 57.0 gr. 6.5 CM - 63091 PSI - Pmax - case volume - 53.5 gr.
It has nothing to do with any mythical efficiency or over optimistic reloading. Its physics.
Yes, it's physics UNLESS you embrace POA and truly believe that you're always going to get significantly more velocity from any cartridge that is "AI'd" than from the non-AI version when all common variable are equal.
