Retumbo for 338 RUM

[Bull oiler]

I just started loading Retumbo in the 338 RUM. I am using 250 gr. Partitions with Fed. 215 mag/match primers. I started at 95 grains working up in 1 grain increments and at 98 grains I was showing pressure signs (slight primer cratering, bolt face marks around primer, and bolt not hard to extract cartridge, but sticky at the top of bolt lift) my average velocity for 4 shots was 3102 fps.
This was an older jug of powder, dating back to 2007. I know there was some discussion here some time back with JD338 using Retumbo and that he had noticed velocity changes from lot to lot using Retumbo.
Can you help me out with this JD338?
I have respectable accuracy with 96 or 97 grains of Retumbo and no pressure signs. I am concerned about the lot to lot consistancy of Retumbo powder

 

[Richracer1]

First thing is get an 8lb jug of Retumbo if your loading for a RUM. I did a while back and I'm loading for 3 RUMs that use Retumbo. I still have a lot left, but to help keep the quantity up and minimize any lot-to-lot variances, I, so far, have only poured a 1lb bottle into the 8lb jug. I then shake it up really well to get it all mixed in. I've loaded rounds with the mixed Retumbo and they still shoot as well as the loads from the un-mixed 8lb jug.

 

[str8meat]

i dont seem to have lot 2 lot issues of mv of retumbo. i shoot 98 gr. in 250 ab getting 3000 fps. accuracy is superb. seeing that you live just over the hill from me could maybe be the air moisture also.

 

[Oldtrader3]

Partitions, by having the brass Partition in the bullet design do reach peak pressure a little faster than Accubonds and other non-Partition bullets do. Plus Retumbo is noted for some burning rate variation fom lot to lot. You are pushing a 250 Partition at over Lapua speeds. Sounds a little too hot to me?

 

[JD338]

I am loading 98.6 grs of Retumbo with both the 250 gr AB and the 250 gr PT. The AB is right around 3000 fps and the PT is 3024 fps.
I just bought a 8 lb keg and my velocity dropped with the 300 gr AB from 2742 dps to 2680 fps.

JD338