Earlier I discussed the the pro's and con's of whether to use oil or grease to lubricate your break open shotgun. What I didn't tell you is that I found out how to avoid that decision. The product I've been using with great results for the last year is from a handgun oriented company, Wilson Combat. They are makers of custom 1911 pattern handguns[ My favorite], AR15's, and tactical shotguns based on Remington 870's. They have a series of lubricants called UltimaLube including UltimaLube grease, oil, and another that splits the difference, universal. UltimaLube Universal is a very thick oil, or a thin grease, depending on how you look at things. I tend to think of it as a VERY thick oil. I use it to lubricate, not as a general rust preventative, as there are other products that do a great job of that. The other really neat feature of the UltimaLube Universal is the applicator. It is a syringe, with a pin point plastic "needle" to place the lube just where you want it, and not all over your hands, shirt, or sweater. Also, the end of the syringe twists, effectively turning the applicator "off", so it doesn't leak all over your range bag or gun case. This stuff works GREAT!
Wilson Combat Ultima-Lube Liquid Universal 10cc Lube Syringe
For rust prevention I recommend 2 items. First for general rust prevention, I like Birchwood Casey brand "Sheath"[Now branded by Birchwood Casey as "Barricade"]. It is a rust preventative, that doesn't leave as "greasey" film as some others, and really does a great job. I like the liquid as opposed to the spray, because I like to either apply with a rag, or a brush, depending on the part of the gun..
PS4 Sheath Rust Preventive 4.5oz Spout Can
Kleen Bore Nylon Bristle All Purpose Gun Cleaning Brush Md: UT221
A rag is great for spreading the preventative on smooth surfaces like the blued barrels, and the brush is GREAT for rough areas like the top of the vent rib, or any engraved areas. Engraving provide a difficult area to treat as wiping with a cloth will just hit the high spots, and since on many finely engraved shotguns, the engraved areas are left "in the white" you need to get rust preventative all over the exposed steel. A brush, like the one above is great for getting the liquid Sheath all down in the engraved surface of the shotgun.
There is one additional rust preventative that I use, and it is very specialized. I use it mainly to treat the inside of the shotgun. Especially inside the lockwork. Especially inside detachable trigger groups, but inside the lockwork of guns that don't have detachable triggers or locks. Many, some, or none of you may know, I shoot a Beretta DT10, a gun that feature detachable triggers. I like to clean and degrease my trigger groups[ the one in the gun, and my spare ], then I soak the trigger group in Sentry Solutions TUF GLIDE....
Sentry Solutions - Tuf-Glide, 1/2 oz.
Sentry Solutions Tuf-Glide 8oz Bottle
This stuff does a GREAT job of rust prevention, with just a little lubrication....and it dries completely so the treated metal doesn't attract and hold grit and carbon. The only down side is that it doesn't have much "staying power" on surfaces that get handled[ The Birchwood Casey Sheath is better for that ], but if the surface doesn't get messed with, like parts inside your gun, it does a fantastic, long term job of rust prevention.
Now, before anyone gets upset that I don't recommend their favorite lube or rust preventative......take a deep breath and relax. These are just the products that I have found work well for me. I have used many more that work well also, I have lubed Perazzi's with motor oil off golf cart dipsticks, and kept Krieghoff's from rusting with olive oil, but these are the products I use when I have a choice. Use with confidence!