What size patch are you using? It's possible the patch is too large and a portion of it is binding against the bore and rod or bore and base of the jag. A short jag can cause this problem. Cut the patch smaller and try that. I've only run into that problem with the jag I use in my .22's, but cutting the patches into a smaller size worked. BTW, the only patch worth using IMO is the 100% cotton flannel variety. The synthetic types (Hoppes for example) are useless if you ask me. Cotton T-shirt material is fair.
Here are some other thoughts:
Hoppes no. 9 smells great, but is fair at best as a solvent. I like using a mixture of Shooters Choice and Kroil (75/25 ratio) to go after powder fouling. I let it sit in the bore for 15 to 30 minutes and then apply some to a bronze brush and brush the bore 10 or 12 strokes. I then wet patch again and follow that up with 2 or 3 dry patches. I have found that MPro-7 works darn well on powder also.
After I clean for powder fouling I may or may not clean for copper. I usually don't worry about copper unless I notice my groups are opening up. For copper fouling I like Wipeout or Barnes CR-10. Wipeout is a foaming cleaner and I generally leave it in the bore overnight. I've been meaning to buy some Montana Extreme 50BMG copper solvent to try, but haven't gotten around to it yet.
I think Boresnakes are good when you need a quick clean, but for a thorough job I prefer the traditional rods, jags, brushes, etc...
If you want to know what some of the serious benchrest shooters do to clean their bores I suggest you go to
www.6mmbr.com and browse around. They've got some good info there on this subject.