View Full Version : 870 Police Magnum--Loose Rear Sight

September 19, 2005, 04:45 PM
I have the short factory barrel. The rear sight rides on a ramped lug attached to the barrel. By tighting the screw on the side of the sight, the sight is designed to clamp on the ramp and stay in position.

The screw appears to tighten but as I fire slug from the gun, the sight move forward. So the more I fire the higher my shots go. I can't seem to tighten the screw tight enough to get it to hold.

I am looking at ordering a new rear sight from Remington. Has anyone else had this problem? Any tricks to solving it?

September 19, 2005, 04:56 PM
Sounds as though you do need a new blade. If it were me, and I were buying a replacement, Id skip the factory part, and go with an Ashley Express or Willams Firesight. I also think Trijicon builds a very nice rear sight blade and mathching front sight with tritium inserts.

September 19, 2005, 08:15 PM
You probably have a defective rear sight base or it's screw.

If you look at the rear of the blade's elevation base section, it has a split at the rear.
This allows the elevation base unit to close and lock in place on the main sight base ramp section.

If the blade elevation unit is sprung, or the Allen head screw is defective, the elevation base won't clamp down and lock in place.

What I suggest is contacting Remington about this.
In all likelihood, they'll send you a new rear sight assembly for FREE.

On Remington's web site is an excellent contact section.

Fill out a contact letter, and they'll get back to you pretty quick.

If you just want to buy a new unit, these are available at:
Check the schematics tab for Remington.


September 20, 2005, 11:44 AM
Thanks for the suggestions. I appreciate them.

D--I tried to locate the sight on Brownell's web site but don't seem to get very far. I can't seem to find the Police model and then I don't seem to find anything with the sights. Any suggestions? It sound like you know exact what part I am struggling with.

L--Do you think Trijicon has a drop in replacement that would work on the existing ramped lug on the barrel?

September 20, 2005, 11:51 AM
Yes, they do

September 20, 2005, 01:51 PM
I looked on Brownell's, and found they no longer list the individual parts.

I'd suggest calling Remington at 1-800-243-9700 or contact them over their online help system.

As far as I can see, the current parts are:
Rear Sight Elevation Slide-- #94335
Rear Sight Elevation Slide Screw-- #90904

If you tell Remington your problem, I bet they'll send you a free replacement.

A note about luminous sights: Remington does sell a luminous rear blade for the standard sight, and a luminous blade for the front sight.
Go to: http://www.remingtonle.com
Which is the Remington Law Enforcement web site, and look at the page for the 870 Synthetic guns.
They show a rear view of their luminous sight for your gun.

Note that if you order a luminous sight from another maker , ALL YOU'LL GET is JUST the rear blade and the front bead blade....NO elevation slide or screw.

September 20, 2005, 04:05 PM
What kind of tool are you using to tighten the rear sight?

I had the same problem when I first got my 870 Police Mag. I kept tightening the rear sight with a flimsy allen wrench and screw driver. I would torque the screws down as far as they would go and they would feel "tight". But then, under the heavy recoil of slugs, the sights would work loose again. Finally (very much by accident), I used a sturdy screwdriver with allen heads from my gunsmith tool kit and the problem stopped. Turned out the flimsy tools just could not provide enough torque and I never got the sight tight enough.

Might be worth a try before investing in new sights.

September 22, 2005, 12:08 AM
Great suggestions. Thank you.

I will try the Remington route and see if I can get a hold of a new rear sight assembly. Brownell's said depending on age it might not be available. I wrote them about my sad story and sent them pictures so it should be pretty easy for them to response.

Otherwise, I am probably looking at some sort of after market night sights for it.

I am wondering if I could successfully squeeze the rear portion of the sight together in a vice or some other method such that it would grip the dovetailed ramp better. It seems like a last resort but it seems a little to much like "bubble gum and bailing wiring".

September 22, 2005, 12:11 AM
Short of getting a new elevation slide and screw that might be a "fix".

Be sure to remove the screw and pad the vise with brass sheet to protect the slide.

Don't over close it.

September 22, 2005, 12:43 AM
Dang, I hadn't really thought seriously about doing that but it might be worth a try. Especially if they send me a new one I don't have much to lose.

D--Thanks for your comments. You obviously know a bit about shotguns and specifically 870's. I appreciate the help.

September 22, 2005, 01:45 PM
I have a gaggle of these rifle-sighted barrels on my 870's and I have had the rear sites self-elevate but it was always because the screw was loose. No jokes.
I have some with allen screws and some with slotted screws. The slotted ones seemed lees prone to this and judging by vitesse9's post, I understand why.
By the way, the AO sites do not replace the offending part and will not fix this. I use the AO's and it is only the top part of the rear site that the replace. The AO's are terrific 870 sites IMHO.

September 22, 2005, 02:05 PM
Mike, thanks for the comments. I will have to take another look.

It does have the slotted screw rather than the alan screw. I just don't think I can tighten it any better. Under-tightening things has never been my problem in working on mechanical things.

September 22, 2005, 02:20 PM
I do like Dfariswheel's idea of the vise trick too. The only other thing would be to peen the edges of the ramp, gently. Those edges are pretty soft. I am thinking last resort though.

September 22, 2005, 03:24 PM
Didn't remember that:

Check the ramp base itself for bent or slightly deformed dovetail edges.

Also, one "Fix" would be to adjust the elevation base and put some Locktite on it.

September 28, 2005, 06:37 PM
Well, I decided to submit an online enquiry. I gave them all the specifics of the gun and several pictures to make sure we were talking about the proper part. After several days, I got a response.

It basically said, "You can order this direct by calling our Parts Dept at 800-243-9700." The did tell me the date of manufacture for my gun.

After a follow up message, they did give me a part number of 103145 for the assembly. I guess I will try to contact them tomorrow.

I must say they were very polite but not all that helpful in their response. I will see how it goes on the phone.