Starting load for a 6.5 Magnum with 147 ELD-M's and Berger EOL 156's

[260shooter]

I'm gathering parts for a 6.5/7 PRC build. Looking for starting loads for the 147gr and 156gr bullets . I have H-1000 and Retumbo on hand.

I can't find a manual with starting loads for these bullets in the 264 Winchester. Thinking that would be the closest case for what I need.

Any help would be appreciated.

 

[Shortschaf]

6.5 Sherman is listed to have 75gr H2O capacity (same as 7prc), so maybe that is a decent place to start.

Here's the Sherman load data compilation

https://img1.wsimg.com/blobby/go/b4083d55-887e-47d6-93bd-312cd4a323d2/Sherman%20Load%20Data%2011Dec21.pdf

Unfortunately, looks like there isn't direct data for the 147's or 156's though

 

[.270]

Based off a 6.5 SAUM with H1000 and 147s, I would start at 56-7 grns and work up from there.

 

[260shooter]

There's a 155 (I think, small print) Cauterucio with Retumbo at 61.5 for 3030 (I think). Would that be a starting load?

 

[260shooter]

Thanks .270. I was typing as you were posting.

 

[Shortschaf]

There's a 155 (I think, small print) Cauterucio with Retumbo at 61.5 for 3030 (I think). Would that be a starting load?

The loads in that spreadsheet are often max or near-max unless otherwise noted.

So that, in combination with @.270 's advice, would have my ladder starting at 56 gr of h1k for the 156's, loaded up to 62gr.

 

[260shooter]

Thanks Shortschaf.

Now I'm curious. I'm going to fill my ADG brass to the neck shoulder juncture with both H-1000 and Retumbo for reference, I realize it will be over max. But I was thinking the 7 PRC would hold more powder.

 

[260shooter]

Looking at the Hodgen website and the 7 PRC, the 6.5/7 PRC's parent case and using 175 gr bullets and Retumbo powder. Hodgen gives a starting load of 63.7 and 46.8K for pressure. Should this be a safe starting load for a 147 ELD-M?
Forty years of reloading but first time having to figure a safe starting load for a semi wildcat.

 

[260shooter]

A 6.5/7 PRC case wolds 70 gr of Retumbo to the base of the neck. With a 10% reduction that makes it 63 gr for a starting load. Does this sound like a safe starting load?