Well ,since i have more IMR 3031 on hand than any thing else. I tried some in the 14" contender 7TC/U with the 'soup can". 25 grains went about 1.8" /4 shots and a flier 2" high. 26 gr was a pattern 3"x 4" and 27 grains was a double group. 3 in just over an inch and 2 in .6 ,2" low. 27.5 grains fills the case AND neck, so I ain't going there! Felix lube and hornady gas checks were used.. I found NO leading ,but a nice lube star on the muzzle. Primers were still round with the 25 gr load. I just MIGHT try the 27 grain load in the carbine barrel to see if it is a barrel thing.