My Rem 870 wing master occassionally will double feed.  when I rack the weapon the empty flies out but two shells feed from the magazine tube.

It's a bitch to clear and would definitely take you out of the gun fight.  This happened twice in Shotgun class, then twice out shooting the other day.

What causes this?  (already changed the mag spring)

had the same problem.  I think the retainer that keeps the shell in the mag tube gets worn from inserting shells.  I bent mine out a bit and it never happened again.  then again I'm half shot in the ass right now sio what do i kjnow?

That happened to me twice, so I switched to a Franchi O/U.

I really hate to say this.... Remington shotguns are not as good as everyone would like you to believe. Guy, what you describe is very common in my work. I put more remington shotguns in for repair than ANY other brand.

The closest thing I've seen to bullet proof is Mossberg pumps. Followed very closely by Winchester pumps.

For autos... The Benelli M-4 seems to to be "all that, and a bag of chips" at least so far. Following that the Beretta, with Browning following VERY closely.

My opinion is worth what you pay for it... but I shoot 5,000 shotgun rounds a week.

Ctg. stop or interceptor latch. (usually).
The ctg. stop is staked into the side of the receiver, sometimes they work loose (or come loose from you pushing the pins out the wrong direction), or the tip is worn.

I hope they are the reduced load variety. [:D]

Most likely the right side shell stop (which is the ejection port side shell stop in a right handed 870).  This stop should prevent the second round from exiting the magazine during the backward stroke of the forend.

Load the magazine with a couple of dummies, pull the forend to the rear – which should feed one round out of the magazine - leave the forearm to the rear and observe how the shell stop holds the second round in the magazine.

This stop may be worn on the hook that stops the round, sometimes allowing the round to jump over it.  It may have lost some tension (it’s also a spring).  It may be binding somewhere.  Or maybe there’s just crud in the hole that the absolute forward most tip of the stop moves in.

If you need a new shell stop, you’re best bet is to take it to a gunsmith.  Trying to replace one without the proper staking tool is really aggravating.

Thanks, All.

I might give Drunkin' Valkyrie's fix a shot.  If that doesn't do it, I'll take it to a Gunsmith.