What do you use?
Nothing. Well, i have a break open inline rifle. When i shoot the 777 I take the barell out of action, scope and all, and wash it with hot water and soap. I run some windex in there as well, but it's cotton patches wrapped around a brush, and hot, soapy, running water, mostly. I have a large sink with a "kitchen hose" or whatever those are called in the basement. When the thing dries, i oil with Remington Oil (green and yellow can). I have done this several dozen times, and the Nikon Omega scope is just fine, but the scope does not get cleaned with anything other than clean water and lens wipes. Before shooting again, i run some tight patches in the bore to remove the oil, and shoot two primers to blow the rest and and to produce fouling.
This works very well for me. Doing this, i can place the first shots into the 2" target.
More recently, i purchased Blackhorn 209 powder to try, and i love it. I also love the Harvester crush rib sabots (easy to load and accurate). This BH 209, i clean just like any other rifle, with bore cleaner and and patches, very easily, folowed by a bit of oil for storage. Also, the first shot is on target, regardles of whether the bore is clean or fouled.
I do need to keep oil in the bore, because my "gun library" is in a somewhat moist basement. Except, that is, when i hunt with the rifles. Then, i just leave them fouled and ready for the duration of the season.
Last December a guy next to me at the range could not shoot his CVA Accura or Omega at 50 yards, could not group his bullets less than 8" and was barely hitting the paper. He noticed my 1" 1 hole goups and finally asked what bullet i was shooting. It turns out that we were shooting exactly the same thing (powder and bullet: 777 and 250 gr. XTP), but he had used bore butter and did not scrub wet patch - dry patch between shots.
So, we cleaned his bore and removed the butter the best we could with windex, TC bore cleaner, and Hopes, and loaded on a bore as clean as possible. He was grouping after the first fouling shot, and figured the trick about using wet patch - dry patch between shots. He was not singular. I saw many guys at the range last fall, and if they had bore butter on their tables or in their boxes or tool kits, they were not shooting well (i was just looking
).
Of course, it's different when hunting. If you fire, leave the bore fouled, and hunt with that rifle in wet conditions for 10 days, at the end of the season you will have a rusted bore. That is why i purchased the Blackhorn 209.
Bore butter is mostly for patch and round ball shooting. I read that TC and some Knight inlines have a tight bore, and that bore butter helps loading the rifles because it makes it easier to push the bullets down into the bore. However, that is not conducive to accuracy. A thick lubricant that changes consistency as temperature varies and gets progressively thicker with fouling is not good. Being mostly solid, it cannot be applied in a uniformly thick layer.