Looking for assistance. Load Data, 300 Win Mag, 215 Berger, Retumbo

[trout004]

Hello LRH Friends,

I am helping a friend develop a load for a Seekins PH2, 300 WM with Retumbo and Berger hybrid 215's. We are starting off with new ADG brass and fed 215 primers.

I know that H1000 might be the easiest button to push for this bullet/cartridge combo, but my friend has a good amount of Retumbo on hand so we are going to try that first.

The data out there seems pretty limited with Retumbo. Can someone please provide min and max charge weight data for this and share their experience with Retumbo and this combo? (PS: I have quite a few years of reloading experience and I completely understand that starting low and working high is recommended to ensure that the shooter leaves the range with eyes, fingers, and a barrel that doesn't look like a peeled banana.)

Thanks for the help in advance!

 

[FEENIX]

Hello LRH Friends,

I am helping a friend develop a load for a Seekins PH2, 300 WM with Retumbo and Berger hybrid 215's. We are starting off with new ADG brass and fed 215 primers.

I know that H1000 might be the easiest button to push for this bullet/cartridge combo, but my friend has a good amount of Retumbo on hand so we are going to try that first.

The data out there seems pretty limited with Retumbo. Can someone please provide min and max charge weight data for this and share their experience with Retumbo and this combo? (PS: I have quite a few years of reloading experience and I completely understand that starting low and working high is recommended to ensure that the shooter leaves the range with eyes, fingers, and a barrel that doesn't look like a peeled banana.)

Thanks for the help in advance!

Contact Berger Tech Support for their latest recommendations.

 

[lancetkenyon]

Hodgdon book doesn't have that exact combo, but here is what it says (Win brass and Win LRM primer):

208 ELD-M 74.5 to 81.0 (C)
220 Sierra HPBT 73.0 to 80.0 (C)
230 Berger OTM 71.6 to 77.0 (C)

 

[trout004]

Contact Berger Tech Support for their latest recommendations.

Can do. Thanks, Feenix.

 

[trout004]

Hodgdon book doesn't have that exact combo, but here is what it says (Win brass and Win LRM primer):

208 ELD-M 74.5 to 81.0 (C)
220 Sierra HPBT 73.0 to 80.0 (C)
230 Berger OTM 71.6 to 77.0 (C)

Thanks!

 

[FireFlyFishing]

 

[trout004]

Phil from Capstone already emailed me back! It was a 5 minute turn around. He supplied the same page that FireFlyFishing posted and the attached data… in case anyone else is interested:

 

[Brathany]

I've found their charges really conservative.

 

[lancetkenyon]

Lawyer loads. But good information. I am usually in the 75.5 to 77.0 range with H1000.

 

[MagnumManiac]

I hope you will be running 3.55"+ COL using Retumbo, it is bulky and will overflow the case with anything above about 78g, the only way to keep it compacted is to 'swirl charge' first then vibrate.
It is highly compressed above 80g, my loads were pushing both 215's and 230's out of the cases overnight. Even with swirl charging first and vibrating.
Good luck.

Cheers.

 

[Greyfox]

I use Retumbo/ Berger 215's in my 24" barrel Remington Milspec 700, 300 WM.
Norma Brass .336 Neck size(bushing), Full length sized off the shoulder. (Redding)
Berger 215 seating: .055" off lands. COAL 3.78"
Fed 215M
Retumbo 77.7gr
Average velocity 10 shots: 2870FPS, SD6,
Precision .5MOA, 5shots…Tested to 1000 yards
Note: Work up loads from a few grains less, check magazine length for feeding, my best accuracy and SD's were achieved with the 215 Berger's at .050" to .060" off the lands. This should be tested.

 

[trout004]

I hope you will be running 3.55"+ COL using Retumbo, it is bulky and will overflow the case with anything above about 78g, the only way to keep it compacted is to 'swirl charge' first then vibrate.
It is highly compressed above 80g, my loads were pushing both 215's and 230's out of the cases overnight. Even with swirl charging first and vibrating.
Good luck.

Cheers.

Thanks for the info. I loaded a few starting at 75 and up to 77.5. Coal was 3.650,". I tapped them down and all seemed to be compressing powder above 76 grains.

 

[slick Nick]

I used 210 SMKHPBTs out to a mile with 7828ssc . That and H1000 seem to work best in my 26 inch 1-10 x caliber barrel on savage rig They both do bug holes 1/2 inch or less when i do my part. so good luck on your load development.