In the center are my two new 400gr bullets. The Razberry is the 4th from the left. The Serviceberry is to it's right. The Serviceberry is designed to work in a 444 Marlin that has had two edges of the loading port rounded out to allow a 400gr bullet load with a SAAMI max COL of 2.555"
Here is a pic of my first test loads with Serviceberry using RL7.
The top velocity was 1910fps with the 41gr load and about .645" for three shots at 50 yards.
Best group was .61" with 40.8gr and a velocity of 1889fps measured 15 feet from muzzle.
I am going to progress up to 41.8 in .2gr increments, The inside case length ends up being about 0.074" less with the Serviceberry and velocity with 41gr was about equal to velocity with 40gr and the Razberry seated at 2.491". I later learned that in my '07 SS, the Razberry needed to be seated to 2.485" to clear the unmodified loading gate. Both the Razberry and the Serviceberry have .375" meplats. Those huge meplats require about 0.010" shorter COL in an unmodified port and 400gr bullets.