View Full Version : Looking for info on Tuning a new 870 Express...

September 6, 2005, 02:12 AM
I am new to Shotguns but am very familiar with 1911 .45 ACP pistols, including extensive tuning and smithing of my 1911. I have spent days reading and have found this forum to be very interesting and informative. I will be picking up my new synthetic 870 Express in a week. I am actually building/putting together a HD/Tactical shotty with a 18" Vang barrel, ATN Digital reflex sights, extended mag tube, M4 Carbine type stock, Limbsaver recoil pad, etc.

I am searching for info on tuning the action on the 870 pump. Info like how much of the metal of the action bars can be removed safely when smoothing and polishing (or is necessary). The action bars are very uneven and rough. Same question regarding the action frame rails and internals of the 870 frame.

Also any other tuning tips like:

* Enlarging and smoothing of the ejection port and has anyone found this to be of worth while?

* Tips or advice on the polishing of the the contact areas of the sear and hammer, or any other areas of the trigger assembly. I will be replacing the trigger spring with a lighter one.

* Any other tuning tips aside dissambly and clean and relube?

* Best smithing and tuning book or DVD video on tuning?

Thanks in advance and any tips or info or links to a thread on this site or any other would be very appreciated.

Best Regards,


September 6, 2005, 02:06 PM
Although there are various ways to smooth the Express up, in reality, you get the best results from just shooting the gun.

Some things you can do:
First, just disassemble the gun and clean out the dirty factory lube and any factory crud or metal shavings.

LIGHTLY break the sharp edges of the action bars. DO NOT attempt to remove the rough machine marks on the four sides, just lightly round the edges.

Make sure the bars are straight and aligned.

Lightly break the sharp top rear edge of the bolt's locking lug, and the rear edge of the locking recess in the barrel.

The trigger group really doesn't need any polishing, since the key parts are already pretty smooth, and will quickly smooth out further with use.
Attempting a "trigger job" usually compromises the assembly.
A shotgun trigger is NOT a pistol or rifle trigger where smoothness is really needed.

If you want to go further, buy a copy of Jerry Kuhnhausen's book "The Remington 870 and 1100/11-87 Shotguns: A Shop Manual"
Price is about $30.00 from Brownell's, and covers EVERYTHING you could possibly want to know about the 870.

Dave McC
September 6, 2005, 05:32 PM
As usual, D nailed it.

The best way to polish any 870 is elbow grease....

September 7, 2005, 08:50 AM
Thanks for taking the time to respond and suggestions. I just ordered the Jerry Kuhnhausen's book through Brownells. I also have his 1911 .45ACP shop manual. I do have the AGI assembly/reassembly DVD. FWIW, the DVD is ok, if the moneys spent is not an objection I think the DVD is good for anyone just starting to own a Remington 870, or someone not very familiar with how the 870 works and assembly/reassembly. Several good tips were also presented.

Any suggestions on good DVD(s) on tactical or combat shooting? I have John Shaw's "Combat Shotgun Seminar". This is a 45 min DVD, entertaining and informative for a shotgun newbie like me. Anyway, any suggestions would be appreciated.

Thanks again, cdc

September 8, 2005, 11:46 PM
Dont forget to address the sharp edges of the inside edge of the edjection port and the edges of the loading port. Usualy they are sharp enough to cut the heck out of the fingers.

September 9, 2005, 02:55 AM
Excellent ideas Radom! I examined the 870 Express before I purchased it but have not seen it for about 10 days. I pick up the 870 Monday afternoon and will examine it further then. I like all of my guns to have smooth slightly rounded edges (instead of rough sharp edges), especially if it would effect reliability like feeding and cartidge ejection.

The 870 I have purchased has a black matte finish. After removing the sharp edges there will be bare metal, bare metal without the matte finish. Do you or anyone else know of a good way of touching up the unfinished areas? I was thinking of using a parkarized touch up pen, they look like Sharpie permanent markers. Any other ideas or options?

Thanks, cdc

September 9, 2005, 01:49 PM
There's really nothing that can replace the finish after you file it away.

Most methods are really nothing but temporary cosmetic "patches" to make it look better.

Some options:
Coat the exterior of the gun with one of the "spray and bake" tough gun finishes.
Brownell's sell these in a variety of colors, and they are surprisingly tough, durable, and good looking.

Another option is to save up your money, and send it out for a military-grade parkerized finish.

September 10, 2005, 01:42 AM
The parts of the gun that will be filed will be limited. I am looking for a patch up or coat the bare metal so the metal will be protected and minimize the chance of rust. Also for those areas to blend in with the rest of the gun's black matte finish.

Ideas or solutions?


September 10, 2005, 02:34 PM
Any one of the cold blues.

One is about as good as another. This will NOT really match the guns original finish, but it'll look better than bare steel.