Where to start? load building.

[paltash]

About two years ago I bought a Remington 700 sendero chambered in 300RUM. I have been reloading for this rifle almost since new. I have been loading mostly from manuals and loads found online.

The first six months of owning this rifle was horrible as I didn't know where my loads were shooting from the constant flinching. After installing a vias brake, jewl trigger and a firing pin to match it, I have come to the conclusion that the only thing that my current loads are good for are is hearing reduction.

My big question is where do you start to building an accurate load? Powder selection? Bullet seating? Powder charge?

Also, I have a neck sizing only die from rcbs, but I was told that it could lead to pressure problems for a cartrige of this size, so I have been full length resizing.

My current train of thought is to stick with the same load after better brass prep, and to follow the thread on here about best use of the berger vld as to the COAL.

One last note, with my current load Im shooting 210gr Berger vld's out of remington brass filled with 93gr of Retumbo, and Winchester magnum primers setting it all off.

I thank you in advance for any replies, and any advice is greatly appreciated.

 

[winmag]

I dont load for the RUM, but IMO, everything starts with the brass prep, and absolute minimal tollerances. Second (IMO) is research for ''accurate'' loads with some ''heat'' ie; bullet/load combo's(including primer) back off the hot ones by 8-10% and work up to them watching for pressure and measuring groups. Third is seating depth adjustment to ''tune it'' to my rifle. Fourth I shoot/shoot/shoot to replicate results so I have the most accurate data to go by for what I need to change.
If nothin is working then I re-check and look for problembs like pressure from the stock on the bbl, or loose rings or mounts etc.

This is the meathod wich has worked for me. Other folks probably have more quallified responses due to more years of hand loading experience.
Good luck.