210gr SMK + .300 Win Mag starting suggestions

[Powder_Burns]

Hello, 1st post, new to the site and forums.

I am going to start playing with Sierra's 210gr BTHP and I wanted to know what would be a good seating depth to start working from.
Should I be on the lands with this bullet, or just off of them?
The rifle is a browning a-bolt medallion in .300 win mag, 1/10" twist. I will be using remington brass with a neck sizing die as part of my case prep.

Also, I do not have any published load data for this bullet, and will be using H4831 until I can acquire some Rx22 or H1000. I'm not sure what would be a more ideal powder to use for the heavier bullets. I'm thinking my max charge would be around 72gr or less depending on whether I'm on the lands or not. Am I right on in my assessment?

 

[Cheyenne19]

Re: 210gr SMK + .300 Win Mag starting suggestions

I tried them .010" off the lands over Retumbo. I've never used H4831 so I can't help you with a powder charge.

 

[95LTZ]

Re: 210gr SMK + .300 Win Mag starting suggestions

I have had very good results with 69.5grs. RL22 w/210gr bullets.
This was safe in my rifle so please start low & work just for safeties sake.
Semper Fi

 

[STI_1911_Guy]

210 SMK worked great for me .020" off the lands. Cant say much about the powder as i used H1000. Reloader 22 works great in many rifles but the temp sensitivity is a no go for me. Its been stated many times but i was shocked first hand how much case capacity variance there is in the 300 between brands. Nosler brass with H1000 @77 and the 210 SMK gave me 2920 fps and it only took 75.4 with new federal premium brass to get the same velocity and the case fill ratio was higher.