505 Gibbs reloading with Hodgdon Retumbo

[mchammah28]

Anyone have experience using retumbo with the Gibbs? I've seen a post here & there discussing it but I'd like to dedicate a thread to it. Theoretically I should be able to load 147 grains of retumbo safely, just wondering if anyone has any experience with that. Thanks in advance!

P.S rifle is Montana Rifle Co. PH DGR model 1999
I have both Federal 215 primers and norma brass both virgin and once fired.

 

[Inline6]

I have read of people using between 143-145gr of Retumbo under a 600gr bullet getting 2450fps out of it. I have no first hand knowledge, just some data I had read while researching the round.