Did someone say light loads in the .303 British...............
Use trail boss starting with the 70% rule and work up.
IMR® TRAIL BOSS® REDUCED LOADS
http://www.hodgdon.com/PDF/Trail%20Boss%20Reduced%20Loads%20R&P.pdf
Or use SR4759 the Speer #9 manual list 16.0 as a starting load and 20.0 as a maximum load with a 100 grain bullet.
NOTE: A reduced load using the sams SR4759 powder and a 150 grain bullet is 21 grains for the start load and 25.0 for the max.
I use 18 grains of SR4759 and the 100 grain bullet to fireform my cases using a rubber o-ring around the rim.
There after just neck size only and let the case headspace on the shoulder and not the rim for maximum case life.
When the cases start getting a little tight to chamber you can use a case forming and trim die as a shoulder bump die to push the shoulder back .001 or .002 for easy chambering.
NOTE: Above is the case forming die and my little finger is hold the fired case from falling out of the die. Meaning this die will only touch the shoulder of the case and not the body of the case or neck.
P.S. I don't know why I'm giving you Canadians all this information after beating both our American Hockey teams in the Olympics and dumping "ALL" your snow here in the lower 48.

I hope all your Canadian beer goes flat.
