RE: REMINGTON MOD 700-300 WTBY MAG
take a look at the shells that were ejected... what did the primers look like.. are they flattened out and extruded into the chamfer on the primer pocket of the brass casing? inspect the cases carefully for signs of nicks and indentions...
a sticky bolt is generally a sign of excessive pressure, weak brass, machining marks in the bore which bind and hold the shell back against the bolt... or as said.. not enough freebore
if you have access to a micrometer or dial calipers measure the OD of unfired and fired weatherby ammo... especially down around the headspace band... if it has grown more than .003 to .004 it's most likely weak brass or just too much pressure... flattened, punctured or extruded primers will also denote this.. you'll see the distinctive machine marks from the bolt on them...
one other issue.. the barnes bullets are longer and the ogive MAY be contacting the rifling if the throat is shallow... when you seat into the rifling or too close to it you build excessive pressure and this can cause an otherwise "normal" load to act like a "hot" load... when reloading with barnes X bullets and the like it is specifically stated that you must seat them further from the rifling to avoid excessive pressure... somthing like .050 inches minimum... whereas with conventional bullets you can generally get away with in the neighborhood of .020 - .030...
just some ideas...