Van, 0.452 bullets are a way way too large to go down the barrel of this rifle. The bullet shot today was sized down to about 0.4501" or 0.4500". It was easy to push down to the powder. Using the 777 powder also seems to affect the desired size of bullets.
When burning Blackhorn powder, a bullet sized to about 0.4503", or 0.4502", can be readily pushed down to the powder in this rifle.