Starting loads for 300 RUM

[MontanaRifleman]

Hey guys, I'll be doing some load developement soon for my 300 RUM Sendero. Never did this before for a 300 RUM, so I thought I would get some opinions on my start loads.

180 E-Tip, 97.5 Retumbo
180 E-Tip, 93.5 H1000
200 AB, 92.5 Retumbo
200 AB, 89 H1000
210 Berger, 88.5 Retumbo

COAL on the E-Tips are 3.685
COAL on the AB's are 3.690
COAL on the Berger's are 3.850

Are these starting loads low enough in your opinion or are any of them too close to max?

Thnaks,

Mark

 

[bigbuck]

92.5 grains of retumbo is a little on the high side for my 300 rum (but) I load for the 210 berger .

Do you measure your COAL from the tipp of the bullet to the base If so do you have an wyatt extended box mag?

 

[MontanaRifleman]

Thanks Bigbuck,

No Wyatt's box, I just have the factory mag and the AB's and E-Tips barely fit. The Bergers are seated to the lands and one will fit at the top of the mag. I would only use the Bergers for extreme ranges, so I figure i will have time to single feed them if I need to. Yep, I measure from tip of bullet to base.

 

[tobehunted]

88 gr of retumbo for the 210 berger caol 3.870 was where i started when i was working the load up for my 300 rum. I went up to 91.6 where i started to get some pressure ( the best load also ) go figure. I chronographed them at 3040 fps. I also worked up the 190 bergers with retumbo and ended up at 94.5 (excellent group ) 3100 fps . Took them both out to 400 yds for group testing and the 210 bergers shot 4 1/2 inch but the 190s shot 2 1/4 groups so i stuck with them.