280 Rem.
Please rationalize how the laws of physics have been defied in 5 cases of each caliber?
I agree, as I stated previously but you obviously did not read, you are correct on how it should be, but is not that way.
5 different guns in each caliber, no coincidence.
How many of each caliber have you worked with and evaluated? I know you are getting very high velocities with at least 1 280.
The velocities you are getting, I've only seen with Federal HE stuff....I won't / can't handload any of my 280's that high. Case expansion is WAY too much. Have you pressure tested your loads by some means?
MM
Have I pressure tested my loads? Depends...how accurate does it need to be? Your casehead expansion method leaves a lot to chance with dealing with thousanths of an inch. I don't trust it to be accurate...starting with human error, and running all the way through chamber/brass/etc differences. I have run my loads through quickload. Its only a computer program, but I suspect it has some redeaming value, and though not 100% accurate, Id suspect its at least every bit as accurate as you hand mic'ing your caseheads.
My 139/140 loads running 3100-3150 fps showed pressures in the 59K-63K pressure range. 60K is SAAMI for the .280 and 65K is SAAMI for the .270. I load mine to .270 pressures. According to Quickload I'm doing ok...my 15 years experience running these loads backs that up...and the varying modern load data showing .280 loaded to 65K back me up as well.
The velocities you are getting, I've only seen with Federal HE stuff....I won't / can't handload any of my 280's that high. Case expansion is WAY too much. Have you pressure tested your loads by some means?
You say you see factory stuff moving that velocity, but you can't handload it that high? The key to your above statement is "I wont...". You wont load that high...thats fine...if you don't want to, I'm not one to tell you what to do. If you're happy, then thats great. Don't fret...lots of people are afraid of loading the .280 to its full SAFE potential. Some people regard SAAMI as the aboslute max...not to be approached...I view it as the safe pressure to load to. SAAMI says its the maximum safe AVERAGE pressure.
