View Full Version : Installing a Front Sight on Mossberg 500

February 28, 1999, 01:51 AM
My Mossberg 500 came with a 20 inch, fixed cylinder barrel (home defense model). Later, I had it modified to take screw-in choke tubes for shooting trap. The choke tubes extend into the barrel beyond the hole for the front bead sight, leaving just a few threads left to secure the sight. So after shooting ten boxes, or so, I noticed my sight was gone, somewhere in the grass on Range #4.

I want to drill and tap a hole into the barrel, past the choke tube where the barrel wall is thick enough to provide enough threads to hold the sight. Is this an unbalanced idea? I'm fairly 'handy' with the basic tools (I like to think so, anyway), but I don't have a drill press, which seems like a crucial tool for this endeavor. I'd hate to take the gun to a smith for what seems like a pretty straight-forward project. Any advice, anyone?


George Stringer
February 28, 1999, 08:44 AM
Boing, before attempting to drill & tap try a new bead. After you get the shank filed down to the proper length to fit the present hole, put a little epoxy or locktite on the threads. That should hold it forever. If you don't want to go this route, do yourself a favor and let a gunsmith install the sight. If you don't have a jig it is very difficult to drill the barrel without the bit walking on you. By the time you pay for a jig, you could have a smith do it three times. As with most smithing work, it is very easy to do it wrong. George


February 28, 1999, 01:50 PM
Hey, why didn't I think of that?

Thanks, George. Adhesive is the way to go. What effect will solvent, such as Hoppe's #9, have on Loctite? Loctite Green is the more "permanent" kind, right, as opposed to Red?


February 28, 1999, 03:11 PM
boing, How or who did you get to put threads inside your barrel,and does it hold a good pattern with the choke tubes with the 20inch.(I have a model 590 I wold like to do that to.)

February 28, 1999, 09:50 PM
I asked around at the local gun shops, and they recommended a smith in the next county.
As to the patterns, well, they're a lot better than they used to be with only the cylinder. Before the modification, I had to stand directly behind the trap house, with my box of shells sitting on it, in order to break targets. Not a desirable position to be in if others are shooting from 16 yards! So having choke tubes, any choke tubes, was a vast improvement.
But I wonder if the guy might have done something of a hatchet-job. When I run my finger into the barrel, there is a drastic 'lip', where the choke tube diameter exceeds the diameter of the barrel. I expected the two surfaces to mate flush, but it isn't so.
Of course, the smith didn't make the barrel or the tubes, so I don't see how he could have caused the lip. You're opinion here would be much appreciated, George.
As for patterning on paper, I haven't done too much of that, and only at very close ranges (under 15 yards), so I couldn't give a really informed opinion.
BTW, it cost me about $85 for the machining and three tubes. I've since bought Winchester extended tubes. They have about 1/4 inch of knurling beyond the muzzle, which eliminates the need for a tool for changing tubes. $12 each, if I remember correctly.
Ask around, or if you can afford it, send your barrel to that Vang Comp guy. He seems to be quite a miracle worker, from what I hear. :)


February 28, 1999, 10:09 PM
Thanks for the info.I have a model 835 also.It come with 4 chokes that I wanted to try to interchange if possible. I wish somebody made a 26" barrel for the 590,that would be the ticket.Who is the Vang comp guy?

February 28, 1999, 10:20 PM
Go to www.vangcomp.com.
Also search the TFL archives for Vang Comp, to hear what folks on this board have to say about him.


February 28, 1999, 10:31 PM
Thanks again boing ,I'll do that.

I'm finally a MEMBER!!! :D :D

[This message has been edited by GMike (edited February 28, 1999).]

George Stringer
February 28, 1999, 11:50 PM
boing, first, use the red. It's holding strength is twice that of the green. As to the lip, that's OK as long as the tube dia. is larger than the bore and not the other way around. A flush fit is always desirable but not always achievable without extra work on the bore. Problems rear their heads when the dia of the bore exceeds the dia. of the tube. Tubes get blown out... It isn't pretty. But yours sounds fine. If you find holes in your pattern you might talk over with your smith extending the existing forcing cone in the tube back into the bore, getting rid of the step and increasing the forcing cone length at the same time. This can really help with the smooth constriction of the column. George

George Stringer
February 28, 1999, 11:52 PM
boing, forgot to mention it, but I've never seen any gun solvents or lubes have any effect of Loctite or epoxy. George

March 2, 1999, 08:03 PM
Much obliged, Mr. S.


March 4, 1999, 01:10 AM
I've seen excesive barrel heat cause lock-tight (the red stuff)fail

I used it to put it to but a muzzle brake on my AK and after going through a 30 round magazine at near full-auto speeds, the muzzle brake became very loose. :)

Dont think a shotgun barrel would ever get that hot, but hey, it could happen.. hehe

Ken Cook
March 8, 1999, 03:50 AM
Red Loctite releases at somewhere between 400 and 450 degrees F. I don't remember which at the moment.
In the Corps, I used red loctite to secure the very heavy protected front sight on the Mossburg M590s and they never let loose. These were guns that would often get 3000 (yes three thousand!) rounds put through them in one day. Just make darn sure that you NEVER use it to lock a gun screw in place if it's something you'd rather not put heat to. It is totally impervious to any solvent in my experience.

Your mind is your primary weapon.