blockb,
Congratulations on your 338RUM Sendero.
I shoot a M700 LSS in 338 RUM and have found it to be an excellent shooter.
Here are my favorite loads for the 338 RUM. All loads were taken from the Nosler #5 manual and are safe in MY rifle. I am using R-P cases and Federal GM215M primers.
200 gr Nosler BT
RL22 90.0 grs
best 3 shot group @ 100 yds .325"
210 gr Nosler PT
RL22 90.0 grs
best 4 shot group @ 100 yds .425"
225 gr Nosler PT
RL22 89.5 grs
best 3 shot group @ 100 yds .450"
225 gr Nosler AB
RL25 97.0 grs
best 4 shot group @ 100 yds .790"
( I will be working with this bullet/load this spring)
250 gr Nosler PT
RL25 90.0 grs
best 4 shot group @ 100 yds .490"
I used the 210 gr PT to take an Elk and 2 Mule Deer and the 250 gr PT to take a WT Deer. All were one shot kills, dropping the animals in their tracks.
Give these loads a try and let me know how they shoot for you. Good Luck!
Regards,
JD338