How is that possible, Scorch - that they have longer barrel life, with MORE velocity/trajectory?
I never said they had more barrel life than the 6.5-284. I said
Folk I know who shoot these cartridges have barrel life well into the 3,000 round neighborhood (except for the STW, at about 2,000). And they shoot faster and flatter than the 6.5-284.
Jim Watson said the expected barrel life was around 1200 rounds, not me.
I agree the 6mm-06 is not exactly nice to barrels.
As for flat shooting, a 6.5-06 will launch the same bullet 200+ fps faster than the 6.5-284. That translates into flatter trajectory.
A 7mm STW will launch a 175 gr bullet at 3,000 fps, much faster than a 6.5-284 can even hope to approach. That translates into flatter trajectory. But there is no free lunch- 2,000 rounds barrel life is not exactly something to write home about.
Barrel life has less to do with powder charge and overbore than you might think. 220 Swifts had a reputation as barrel burners, while 22-250 do not, and they have comparable case volumes. My old 8mm Rem Mag burned 80+ gr of powder each time I touched it off, and there was no discrenible throat erosion when I sold it. Barrel life has a lot to do with barrel temperature, flame temperature and working pressure. The 6.5-284 operates at high pressure.