Originally Posted by Andrew Wiggin
Yes, compressed powder might be an issue but the bearing surface of the bullet is the primary factor affecting chamber pressure. The Barnes technician advised me that I should treat this bullet about the same as a 200 gr jacketed bullet, even though the 155 gr all copper is longer.
The bearing surface is a non-factor. Only about 50% of the "bearing surface" is actually .400". The .40" bullets taper up from the base from .393", to about 1/2 way. The other calibers are similar. Maybe the engineers knew something?