I can not get the bore of my HK 45 clean. No matter what I do there  remains some fouling near the muzzle.  The fouling seems to be in 3 spots near the grooves.  I've tried running patches with hoppes 9 down the bore letting it sit a bit then the running clean patches til they come out clean. Even after the patches come out clean the fouling remains.  I've also used a bore snake and a plastic brush with solvent to loosen the fouling with no luck.  I've also tried bore scrubber as a last resort.  Any other things I could try?

As a last resort, an old bore brush wrapped in 0000 steel wool soaked in oil.  Or, one of those stainless steel tornado brushes.  No disrespect, but just have to say, be real careful with either.

How about a conventional bronze brush and cleaning rod?

Is it leading? Hoppes #9 is fine for carbon fowling and powder residue, for lead or copper deposits it's so so.

I like Shooter's Choice, but lots of other products are just as good.

I would not use a stainless steel bore brush .......................ever. Bronze is as tough as you'll ever need and should make short order of any copper or lead build up.

H&K barrels have polygonal rifling the last I knew. Polygonal rifling and lead bullets do not play well together.