i had the same problem with my staghorn when i first got it. and i fixed it the only way i know how.... curse, WD40, curse, elbow grease, more elbow grease, curse, some hot water, and finally CHEER. but no really its a pain in the A$$.

i pulled the barrel off and clamped it to my bench, and used allot of anti rust and solvent on it. it took about 20 minutes to get it out. but once i cleaned it, i make sure it always gets a nice coat of hoppes gun oil and CVA anti seize stick. and i will come out every time.

good luck, and don't get frustrated with it. love thy gun..