I don't have a 6mm ARC but do have a .243 and improved 6mm. I question whether most of the bullets mentioned in this thread are soft enough to expand sufficiently at the very low 6mm ARC velocities, given most of the 6mm bullets are designed for the higher velocity .243 and faster. Especially as you get out around 350 yards or more. I have a 6.8 SPC and the best bullets for it are specifically designed for the lower velocities e.g the 6.8 110 TSX (as opposed to the .270 110 TTSX which was designed for .270 velocities and is too hard for the 6.8 slower velocities), 6.8 110 Accubond (which is a bit soft at full-power .270 velocities e.g above 3000 fps).
Think We may better state a goal of a minimum impact velocity. My personal goal 6mm ARC with the CX or E-tip looks to be 2400 FPS, again (impact velocity) Ill be expecting a muzzle velocity of 3050 fps give or take 50fps. will chronograph loads to verify. So yes ill agree a 350 yard shot should not be considered due to expansion concerns. Though I do see a 250 yard shot , well placed shot as being very ethical.
If the shooter is not able to place the shot well, than caliber & even velocity may be a null point.
So if you intend hunting beyond 250 yards then a larger cartridge, or longer barrel may be encouraged, Ill agree. And if we are looking at a 16" gas gun with the tougher monolithic bullets for example, then 125 yards may be the upper limit in terms of expansion with most monolithic projectiles.
