I've owned a non-Browning 12ga box lock for quite some time. Never shot it much myself...but it's a used shotgun I picked-up somewhere(think I got it at a gunshow). Anyhow...I noticed it in the gun closet while digging an ancient Lefever double out.

I took both the old double-guns out and cleaned/oiled them. Got to admiring the old Belgian shotgun and tried to find some info on it. About all the info available on this particular model FN(Fabrique Nationale) is that it seems to be referred to as an 'Anson' model..has ejectors and a rotten horn buttplate...'Greener' crossbolt lock-up.

American Rifleman | Filling a Niche: FN's Early Side-by-Sides

This American Rifleman article is virtually the only online info available about these shotguns. There are a few online auctions for these with pics..but they don't seem popular or sell that well. If I recall I didn't pay much for it myself(like maybe $150 in the early 2000's).

It's a good shooting gun I remember..the only issues I recall was that sometimes it would eject a live shell if you opened it to fast. Plus it's a real bear to get the forearm back on if you break it down!

I thought I might repair the worm eaten butt plate and use this old shotgun for some fall hunting.

Any tips on fixing a wormy horn butt plate?..I figured fill the voids with epoxy is about the only option I can think off??

Any advice or experience regarding reassembly of an ejector-double? I can get it back together however it's tricky and I'm not certain I'm doing it properly!

Thanx for any info..Stevie

Leave the worm holes. They are kinda super chic.
If you have chips etc, use epoxy, with black dye added.

Charlie

One of the local gun fixers used any color 1/4" thick plastic a customer wants. Black is the most requested. Wrap the butt in 2 layers of masking tape, screw the new plastic in place, and literally sand away what doesn't look like a but plate. Use a tri-angle file to Checker or texture as desired. When you're used to it, it's a 20 to 30 minute job. This works great for guns that don't have the value to put a exact replacement on.

Ivan

Many of the old black grips and buttplates used in Europe were apparently made of some sort of rubber (I think it was called Gutta Percha) filled with fine sawdust (wood flour) or horn dust. Whatever, they were tasty for bugs to nibble on. I have seen many of them with insect holes but I don't think I have ever heard of a way of repairing them. I have a pair of grips from a FN-Browning Model 1900 pistol which are riddled with holes.

Supposedly 'horn' is the material this buttplate is made from and it looks it. Multi-color from golden amber to brown and black and has some big holes/eroded places in it. Cool buttplate with the FN logo carved into it..I've got to fix it somehow...or replace it.

I've got some older FN Browning pistols with 'horn' grips that are sort-of black. My FN 1900 has one horn looking grip and one plastic/bakelite grip. My FN 1910 cracked a horn grip the first time I shot! I glued it back with super-glue...but later installed a set of 'FN' logo reproduction grips and saved the originals back. Pretty certain my little FN Browning 1906 6.35mm(.25acp) has horn grips. All those appear more or less black. None are as colorful as the 'FN' logo buttplate on the shotgun. Maybe they stained the pistol grips.

I think you're right about the composition of the FN butt-plates/grips. I for the first time(in my ownership) removed the old FN shotgun's butt-plate. While it appears to be..at least to me..a hunk of carefully carved 'horn'...it has a molded/cast in oval on the reverse side with obvious mold marks and '1 H' molded into the oval....That may explain how the 'FN' logo and horizontal texture is so perfectly done(less worm damage)!

I suppose maybe FN had some proprietary method of molding 'horn' butt-plates and pistol grips that may appear to be 'hand-carved horn' with grain(like wood or natural horn) but isn't...I wonder what 'Gutta-Percha' really is??....Almost reminds me of the old long strand gun-powder nitro-cellulose(ever torn down any ancient smokeless ammo full of long strands of 'plastic powder'?)...Yeh...I don't think natural horn would melt and mold..it would char and burn!...Them sneaky Belgians!

Those butt plates are made from horn,,usually water buffalo horn'
It was impressed with the FN logo and also given any slight curve shape by simply dropping the shaped horn butt plate into boiling water. Let it sit for 45seconds or so. Fish it out,,it'll be very pliable.
They then placed the plate blank in a mould then closed the mould for a couple minutes to allow it to cool sufficiently to a static state.
Removed and let set to fully cool it hardens back to it's original state but with the embossed features and the curve permanetly set.

You can still use the process to re-shape old horn butt plates, grip caps and trigger guards, the latter common on German & Austrian firearms.
In fact I used a worn FN A-5 horn butt plate to replace the battered remnant of a pad on a German mfg double rifle not long ago.
Re-curved to fit the D/R stock with the boiling water method using the stock itself as the 'mould'. I then filed the FN logo off and checkered the plate in the style of the grip & forend checkering already on the rifle.

Many of the older horn plates have started to come apart in the thin layers of mat'l they are formed of,,especially around the edges of the butt plate or grip cap.
A thorough dousing with common super glue to those area will seep into those delaminations deeply and hold the mat'l back together w/a strong bond. It glues the nat'l horn mat'l very well and quickly,,just like it will do to your skin!.

Filling those worn holes commonly found in horn I've found either an epoxy mix with a couple different shades so you can alter the look around the plate as the color of the orig matl changes.
Sometimes I use shellac stick filler. That works well too but you have to be carefull with the heat you use to apply so you don't damage the horn itself..
Super glue dribbled into bi-carb/soda put directly into the voids works well too. The Bicarb acts as an accelerator and sets the super glue up immedietly.
So you can sand or even file it to shape. Add more glue and Bicarb to build up the area if needed. It's quite strong and can be used to fix all sorts of butt plates,,plastic, horn, cast epoxy.
One problem is the color,,an opaque white that does not take stain too well , but will color with some alcohol stains. I've had some luck coloring the bicarb powder with a black coloring agent to color it too (copier toner),, but it still won't be jet black when done.
For the older GuttaPercha grips and plates it works good for filling voids but again the color needs matching up.
Still works pretty good on the multi hue horn plates.
Thanks your gunsmith trick of the day.....!

Also works good for fixing small chips in wood checkering ect where you can dummy up the finish and color to hide the repair.
It's actually a trick used by wood carvers to fix small imperfections on their carvings that are going to get painted over.

The FN sxs's are very nice shotguns. The side locks were made up into very high grades.
The ejector(s) sound like they may not be holding in the cocked position. That will cause you to use a lot of effort to re-assemble the forend onto the gun as you are pushing the ejector hammers (commonly called the 'kickers') back into the cocked position.
If they are not holding there in the cocked position they will eject the unfired shell(s) every time the gun is opened, which is what it sounds like it's doing for one bbl. That bbl's ejector needs to be looked at.

Me and my brother both had FN doubles. He got his at auction
one night when we bought several above average DBLs. They
were all 16g and going cheap. Lefever, FN, Fulton the young
crowd there had no interest in them. I got mine from a divorce
sale. Guy told me it was a WW2 bring home by a uncle. We had
them at several shows before selling them. One brought $550
the other went on a trade that I can't remember.

I figured out my reassembly problem(I think)...Worked on the FN yesterday evening...packed the butt plate holes with epoxy...and disassembled the forearm. The forearm iron is a complex and compact assembly with 'kicker hammers' sears leaf springs..cocking rod for all that stuff..not to mention the retaing latch mechanism...

The pieces all appear fine and functional although it does have what appears to be a 'gunsmith made' leaf spring for one kicker.

Examined the assembly to see why the kick hammers wouldn't stay cocked....but would stay cocked installed on the gun. With some effort I managed to manually cock the kicker hammers and the the iron would plug right onto the rest of the shotgun.

It seems the FN shotgun is sensitive to the position it's in when you take it apart! If you just plop the gun in your lap upside-down and remove the forearm the kicker hammers un-cock as soon as you pull the forearm. Same goes for standing it vertically and pull the fore-end off..it uncocks the kickers.

The kicker sears are free-swing...and gravity will rotate the sears out of engagement if the fore-end is removed with the shotgun in any other position than horizontal with the forearm on the bottom!!...

Weird deal.. and I don't see any sign of missing springs or anything like that in the fore-end iron ejector mechanism. Maybe just the way it is.

Wish I had a parts diagram for this older gun...but alas...no such thing exists online.