Originally Posted by BLUEDOT37
You didn't tell us what velocity you got or what manual you got your reference velocity from?
If you got it from Hodgdon's, they use a 10" barrel for their tests.
Quiet sorry about that, didn't take the time to post the details like i usually do, but as follows:
Average: 1292.8 fps Standard Deviation 5.0, 586 ft. lbs. energy
The 17.0 load was suggested by Lyman's 49th for the XTP, which also listed the same maximum load for 2400 that Sierra advised me to use, so i used this as equivalent data. I saw to other suggested maximum loads, both from Hogdon's website and also from an old NRA Reloading handbook that took a load from the old Speer super hot book of 17.8 grains! So I went with Lyman, who tests a 4 inch barrel, 1309 fps average listed, and a maximum average pressure of 38,400 CUP So, knowing the old MAP of 357 Magnum is 46,000 CUP, I was only testing a few loads for gel and curiosity, and the strength of a 2000's manufactured N frame, i did the most reckless reloading decision of my life, actually using a maximum listed load for a cartridge hand weighing every charge to .1 of a grain.
Cases extracted easy.
Primers didn't look too bad, but I'll take anyone's take on the looks of those as well. My tight new manufacture barrel was doing under the average of Lyman's 4 inch barrel test, but there are enough factors to explain that, too, I suppose, different bullet, lot of powder, primer, and the fact I don't crimp my cases like a gorilla, leading to perhaps less than high end performance.
Incidentally, I accidentally found my father's old Sierra handbook I thought was lost looking for more information this morning, which also lists 16.3 grains H110, 1,200 FPS out of a 6 inch Colt Trooper Mk III.
Looks like I'll be toning them down in the future. Still have a gel test I plan on doing using the Magtech SJHP, but I suppose no need to hot rod em.