I am new to reloading belted cases. I've got 50
pieces of new PMC on the flight line and I'm frankly
a bit nervous about launching them.

My setup is an RCBS Rockchucher and a Redding 3 die-
deluxe set. The cases have been uniform trimmed
and the touch holes deburred. I'll be using RL22 and
Federal GM bench rest, large mag primers

Are there any tricks to setting up the dies for new
cases that I should know? I am most concerned about
setting back the shouldes too far.

I am planning to start with a COAL just a bit
shorter than the magazine on my rifle, try a test
round for feeding, extraction etc. I will stick
close to the Barnes book on the 100 gr XLCs I will
use.

Thanks.
1B.

Sounds to me like you have an excellent "flight school" going on. Don't worry about setting the shoulders back too far--as long as your die just touches the shell holder you won't push on that virgin brass.

After you've done your first firing set the die "up" from the shellholder about 3/4 turn and do a sizing. If the shell won't chamber then make small 1/16 turns of the die down toward the shellholder till they do chamber and you've just "custom fit" the sizing process to your individual chamber.

RL22 was an excellent powder for my 257 wby. I'm not sure what it is about the .257 but it seems to be one of the most inherantly accurate of the wby calibers---good luck have fun. Kraky

1B I have found RL22 to be a good powder but RL 25 is even better in the 257 Wby. I have also found that my rifle delivers better accuracy with std primers. I also agree with you about not wanting to set the shoulder back.I would suggest you back the die out approx 1/2 to 1 full turn from touching the shellholder. This will ensure you are headspacing on the shoulder and not on the belt. Case life will be greatly improved.Kraky has the correct proceedure for setting that size die.

1B, they have given you GREAT advise. I have used the same ideas while reloading .270WBY, they work well. I eventually started using IMR 7828, but RL 25 should work just as well.

Where powder is concerned, slower is better in the Weatherby line.

I have loaded for a 300winmag with good results using re22.
As far as sizing, I use the Redding competition shellholders. After brass fired, they allow the die to touch shellholder, but not set shoulders back, or at least not too far. The set as several different thickness shellholders, so you find the one that works best in your chamber.