Factory Second Bullets 303 Caliber and 7.7mm Japanese

[usabaker]

3. Best results can be expected from bullets with flat base and not more than ~.002" under measured groove diameter.
4. Boattail bullets offer less bearing surface than FB of same weight, making them a challenge in military chambers with generous throats. (They can yaw before engraving).

I agree with you. In addition, I would expect that a Flat-Base open end (exposing the lead) would obturate faster and better than closed-base bullets.