Originally Posted by Gary Morgan
J E Custom, thanks for your response. I am curious what primer you would suggest I change to. I am using the Federal Gold Medal Match Magnum primer. I thought it was odd that the 91 grain charge was faster than the 92 grain load, and then 93 and 94 shot the same speed.
I have the bullets about .010 into the lands, and I was anticipating maybe getting 3,200 FPS out of the 28-inch barrel. I wonder if I should try moving the bullet back off the lands to hopefully gain a little velocity.
What do you think?
I think you are on the right track with 94 grains of Retumbo. there seems to be a lot of RUMs
that like this load. go up or down in 2/10ths grain increments and you will find the NODE.
I all start with the bullet farther away from the lands so that I can find the MAX load without
any problems and then adjust the seating depth to tweak the load.
I would back off to .020 to .025 to start with and try that first. I like the 215 M but would
try a 91/2 rem primer or a 215 (NO Match) they are a little hotter so watch for pressure
The other thing that could be effecting SDs is bullet grip . check neck thickness and if it varies
you need to turn them for a more consistant grip on the bullet.
For best results only make one change at a time or you may mask a really good load potential.
The RUMs are very forgiving and load development should go fast if you are careful to keep
tract of any changes.
The only problem I have with the Retumbo is that it can become critical (Over pressure) very
easy and case density is not where I like it.(I prefer 99 to 100%) but it does have it's following.
Just some thoughts.
J E CUSTOM