I've had this gun for 5 or 6 years and have ridden it hard.

Won't cycle dove loads very well anymore. I took everything apart and cleaned it and put a new o-ring right beside the piston assembly.

I shot a box of remington hi brass this morning just to test it out and was getting jams about once every five shots.

I had been oiling the magazine tube...someone told me this was a no no.

I am typically shooting 3" steel loads through this gun. Maybe the steel will cycle since I have cleaned it up and put the new o-ring on.

What do yall suggest? (besides throwing it out with the rest of the problematic 1187's)

Get a pipe cleaner and scrub out the gas ports. (Little holes going from the barrel to the gas mechanism). Sometimes they can get clogged and won't let enough gas from a light load pass through and fully cycle the action.

If you oil it use VDERY lil oil. I use 409 and a scotch pad to clean my Beretta gas shotgun.Then I take a drop of oil on my finger and rub it on the bolt and few other parts.

Do those have a recoil spring in the stock. If so I would imagine it probably needs to be cleaned It can get gummed up and slow the action down

Yep, cleaned the little ports with a drill bit (yeah a little overkill). I think that was the most helpful thing I did. It got to a point where it was literally a single shot shotgun.

Yes it does

I always use a drill. If the carbon is really baked on it's about all that will get it out.

It's already been mentioned but cleaning the recoil spring and tube in the stock may help too.

Get all the oil and gunk if there is any off the mag tube. I degrease and wipe them off with brake cleaner. then lightly oil it back up just enough to keep it from rusting

Thanks. I think I'll try to get the recoil spring a little bit cleaner.

Whew!
I thought you were going to ask 1,187 questions!

Give it to me and buy another gun problem solved.