This may go in the gun forum better but I thought I'd start here since duck guns have a higher chance of getting wet.

My 870 Express got left in the rain in its non-waterproof case and stayed for about 48 hours. I'd like to blame someone else but it was really my fault in the end. There is one significant spot of rust and several smaller spots. I was able to wipe off the surface corrosion but the surface has been affected. I usually keep it wiped off an oiled after every use. Is there some treatment to prevent the affected areas from getting worse. should it be sanded down some and recoated somehow?

I figure you have two options here. I have 2 870's that have the same coating. It looks to be some sort of powder coating. I used to deal with powder coating when my son was doing racing karts and this stuff reminds we of the stuff we used on his chassis when we redid it.I used to use a place in Mesquite called Enduro Coatings. They could bead plast the old coating off and recoat our parts. If they can get this stuff I bet they could redo this barrel.
The other option would be to just keep it oiled. I bought one of my 870's used and it had a little rust on the barrel. I've been hitting it with a little Hoppes #9 and then some Rem Oil and it actually looks pretty good.

Hell no, just oil the shiat out of it and roll brotha. Dont get caught up on the aesthetics of that gun. That gun is a hunting gun and that is it. It is nothing to look at but a very reliable solid piece of hunting equipment. If you pump that gun good and dont let the magazine spring rust in two like mine did, it probably will never fail you. Thats like asking if you should recoat a hammer that gets slightly rusted. Oil and hunt. Never leave guns in cases after the hunt especially salt water. Wipe the surface with oil, then give a light spray in the action and action bars then work the pump several times. Also run a lightly oiled patch through the barrel and thats it.

000 steel wool and paint it

Outside is not worth worrying about(just oil & rub). I would aim my concern to the inter working parts of the gun and gun barrel.

its a duck gun. deal with it.

x2

In progress

I may go with the paint job if it continues to be a problem. After all its a $250 gun and not a $2500 one. I want to take care of it but probably shouldn't be so uptight.

I am the same way. I grew up hunting with old hand me downs and now I have nice firearms and hate to use them.

An 870 is like an AK47, made to be used and will take a lot of abuse, a lot more than most people will realize. The Infantry used them in Vietnam, a little rust was normal and that was with cleaning on a daily basis, along with shooting a shot pot full of shells. Never saw one jam even after going through rain and mud holes.

Same here, that .410 pictured was given to me 35 years ago, it was me first gun. Ended up getting left in a storage unit that leaked... Next thing you know, I had rust. I'm not done with it, but other projects have taken precedence

I bought some stuff from Scott over at Euless Guns & Ammo.
It's a small bottle that has a cloth in it, and it's soaked in rust remover/protectant. Worked like a charm for surface rust.
Can't remember the name of the stuff. Was like $8 for the bottle, and you can re-use it.

Thanks I'll try and check that out. I don't care that much about the asthetics but I just don't want it to get worse.

I'd have a problem with someone that had an 870 that didnt have a little rust on it. For me I would just make sure your choke tubes don't get locked. My buddy had that happen but at least it was a mod patternmaster.

Its nice to have something fun to work at like that. I'm looking forward to seeing how it turns out.

Your first gun is a good idea for a separate thread. mine was a bolt action .410 from Otasco that I got for Christmas 32 years ago. My dad had to cut the stock off so I could shoulder it and reach the trigger. My first kill with it was a squirrel and my grand mother made squirrel gravy.

Brownells sells a parkerizing kit. You spray it on and bake the gun (or barrel) in the oven. I have done several guns, it works great.

Wait till your wife is gone though, cause it STINKS.

wasn't meant to be a threadjacker, just showing you a rusted gun, and what can be done with it

I didn't think you were threadjacking, I appreciated the pic. I was just waxing nostalgic for a minute.

I really enjoyed seeing the before and after pics as I am a gun kinda guy. I would also liks to see the finished product.

.........its an 870 Express!! Its meant to be abused.

Dab a little black rattle can on it with a cotton swab if you can't live with it.........otherwise, shoot a little oil on it and get to huntin

2 days is nothin'. Few years ago my 870 was left at the lake for aver a week laying in the mud(long story). I went back found it. 000 steel wool like someone else said, and a lot of elbow grease. That thing is still a duck killin machine to this day. I named it TANK for a reason

Here's some 870 abuse from last season. Completely submerged in Barney Lake and then shoved about six inches in the mud on the bottom. Didn't disassemble it, just washed it out with a garden hose and a little Rem oil. Finished the season with it and then cleaned it up. We installed a comb raising kit on it and my son shot skeet with it most of the summer and it hasn't skipped a beat.

The 870 is one of the toughest guns I know, when I go to the coast I come back and throw it in the shower and give mine a fresh water wash down and dry it down real good, then I oil the heck out of it. Like they say wipe it down with oil and go hunt.