I've been reloading for many, many years and understand, and can recognize pressure issues. However, I've been handed a Model 660 Remington in a 6.5 Magnum, 18 inch barrel (carbine). My brother and I owned 2 of these rifles for 35 yrs. I sold mine many years ago because same problem and the magazine is built too short. The one in my hands now has ALWAYS had a stiff bolt upon ejection of re-loads. Factory loads are NO problem. But re-loads at any load I need a 2x4 to snap the bolt back. NOT on bolt lift. It's OK lifting the bold, but to pull it back 75% of the time it needs a swat or better said, a tap to get the bolt to slide back. I'm working on load recipes in groups of 3 and within the same group either 1, or 2, will be stiff and the other no problem. I'm loading well below the books MAX recommends. ie Nosler 140 gr AB and 4831 goes from 51 gr to 55. I start at 51 to 53gr 4350 book starts at 49 to 53gr. I load 45 to 48. All loads or groups same issues. Gun Digest 100 gr Hornady - 4350 starts at 52 to 56, I load 52 to 54. H380 starts at 47 to 51. I load 47 & 48. Same issues.