Shotgun barrel without vent rib, bead protrudes into the bore very slightly

[41magsnub]

I have a 18.5" Mossberg branded 870 cyl bore barrel that I have never fired a round through.  Have had it for years.  Was cleaning guns and figured I should oil up all the various accessories while I was at it.  I can feel the base of the bead in the bore just barely, it very slightly protrudes.  This seems wrong to me, but all my other various shotguns have vent ribs so I don't have anything to compare it too.  Am I over thinking this, or should it get filed down flush (by a gunsmith).  Obviously I'm worried about it dragging on the shot cup, increasing the pressure and doing something "bad"

Can't seem to get a useful picture of it.  

[AJ Dual]

Pretty normal. They're drilled all the way through on non ribbed barrels.

If it bothers you, unscrew the bead. Get it hot with a propane torch to break the Loctite, and use a small hex socket to remove it. Vise Grips on two flats of the little nut under the ball will work, but you'll probably bugger it up.

 Then dress the bottom of the bead's threaded post with a file a few times to knock a fraction of a millimeter off of it so it's flush with the bore, then with a drop of high temp red Loctite, screw it back in.

Personally, I'd pattern it with the chosen load to see if the shot and wad even notice first.

There's hundreds of thousands of Mossberg 500's out there with this and it's not really a problem.

[Triphammer]

If you just feel it, it's not a problem. Put a little fine sandpaper, wet dry/ emery on a 1/2 dowel & work It down. When I put a new bead on a shotgun barrel I'll usually seat it all the down w/ some Loctite and remove most of the stem with a 1/4 - 3/8" mounted stone in a Dremel and finish with the wet/dry on a dowel.

[RoadKingLarry]

Is it actually a screwed on sight or is it staked?

[230RN]

Local BigR has a pair of youth-sized single shot .410s where I noticed one of them has that problem, the other doesn't.

I figure if I spot that, I'm going to eliminate any potential problem, no matter how small.  I figure someone spent a lot of money and finishing to make a nice clean smooth bore, why screw that up by allowing a sight bead stud to protrude into the bore?

Just my sense of Justice and Good and Nobility and The Right Thing To Do, whether it could affect the patterning or not. :)

Terry, 230RN
 

[41magsnub]

Is it actually a screwed on sight or is it staked?

Screwed in.  Well, it could be pressed in I guess but I doubt it.  There are no stake marks.

[AJ Dual]

Screwed in.  Well, it could be pressed in I guess but I doubt it.  There are no stake marks.

If there's the tiny hexagonal nut-flange/base under the bead, it's screwed.

[mtnbkr]

This is actually pretty common.  I've seen it on old and new shotguns.  Easy to fix as AJ pointed out.

Chris

[Tuco]

I shot two rounds of skeet without a choke tube.  Never noticed until I got home and saw the tube on the bench.
scrubbed out the threads and screwed it back in.

Ive heard of FITASC and high ranked (A, AA) sporting clays guys taking the tube out on purpose, so the wad would strip off a bit sooner and open up the pattern.

In short, it won't hurt.  And USA bbls have so much extra steel on them that they'll handle more pressure than you'd get from all but the stupidest handloads.

If it bugs you, pull it out and file.it down. 

[Scout26]

It's an 18.5 barrel.  It's only real use is HD.  So a wee bit of bead sticking into the barrel isn't going to change the ballistic pattern at the distances you'll use that barrel for.

[41magsnub]

It's an 18.5 barrel.  It's only real use is HD.  So a wee bit of bead sticking into the barrel isn't going to change the ballistic pattern at the distances you'll use that barrel for.

Well..  my concern was it blowing up in my face, hadn't got to the point of patterning just yet! Since the slight protrusion is kinda normal in Mossberg world I am less concerned, but am still going to do something about it.

Edit - turns out I did have another shotgun in the house without a vent rib.  I forgot I was gun sitting a Remington Model 31 16ga for a buddy.  Remington managed to do a bead without it protruding into the bore back in the 30's and 40's.