My brother and I bought 2 - Model 660 Remington in the 6.5 Rem Mag caliber in a 18.5 inch barrel about 40 yrs ago. I didn't keep mine for very long for the reason below.
Factory loads eject NO problem. For all HAND loads I need a 2x4 and a light tap to pull the bolt back. The lift is usually OK, but sometimes a wee bit stiff, BUT NOT OFTEN and not bad.
Now before you say it's excessive loading, hold on. I've been loading for close to 50 yrs. This is the only gun I've ever see do that predictably. No let me list for you the loads.
Sierra HP Varmiter 85 gr, 4350 @ 52.5 gr and up to 55.5 - all stick, every one.
Hornady Spire Point 140 gr, 4831 @ 49.5 to 51.5 MV avg 2500 fps
Nosler AB 140 gr, 4831 @ 51 to 53 MV avg 2500 fpc
Factory Rem Core-Lokt 120gr, MV 2800+ fps
Primer pockets aren't stretching, I have around 5 shots out of the bras and no sign of cracks. Primers aren't moon cratered any more from my light loads to the heavy loads.
We're sure looking for a