Some of the information given above might not be safe.
Berry's has a special note for the 148 gr DEWC.
"When loading for these bullets, you need to use data that will attain 800 fps as a minimum. Most of the data for this bullet weight was created using a dead soft lead projectile with velocities under the 800 fps and will not work for a this bullet at those lower velocities."
I have stuck a Rainier DEWC in the barrel of my M14, about 5 inches out. The situation with the copper plated DECW is that there is a large amount of bullet in contact with the barrel.
Best,
Rick