300 RUM Loads for 220 and 240 SMK's Needed

[rangerman1]

I have been selected to test the brand new Berger .30 caliber 230 grain hybrid bullets. The folks at Berger told me to look at the load data for the 220 grain SMK and the 240 grain SMK and start my load development somewhere in the middle of these two loads. I have a considerable amount of Retumbo and some H-1000 powder. Also, I plan to use the Nosler brass and Federal 215 primers. I would appreciate any load data you have using either of these two bullets in the 300 RUM. Thanks in advance for your help.

 

[40X Guy]

Retumbo is the go to powder for the .300 RUM. With the 230 grainer you want to help develop, alot depends on your barrel length, and how deep you are seating them. You have to be careful, I am using Nosler brass also with 93 grains of Retumbo behind both 208 A-Max and 210 bergers. (My rifle is a custom 28.5 inch Brux HV barrel on trued 700) I would say without knowing any other info on your combo start around 85 grains and go up in .5 increments until you start seeing pressure signs. Shoot a ladder test while you are doing this.

Frank

 

[rangerman1]

I have heard of the ladder test but could you please explain to me how to do this and what to look for? I may have it wrong but I understand you load your loads starting low and safe and increase either .2 grains or maybe .5 grains and watch the vertical POI on the target. Where the bullets POI quit rising and stay very close without much vertical dispersion on the target shows that those several different loads are where you need to begin to tweak to find an accurate 3 or 5 shot group while maintaining as much velocity as possible without sacarificing accuracy. Of course you want to wach for pressure signs such as flatten primers and a stiff bolt while doing the load development.
Thanks for your help.

 

[40X Guy]

http://www.6mmbr.com/laddertest.html

Read the above and then do a search on the forum, you will find hours of info. You are on the right track. 300 yards is the accepted minimum range. My friend shoots his ladders at 600 yards with his 30 cals.

Frank

 

[rangerman1]

Thanks for your help. I really appreciate it and will begin ladder testing when my bullets arrive!