A company the specializes in the FN is: Armscorp of America,Inc. 4424 John Ave Baltimore,MD 21227 Ph#(410)247-6200..... However our host shows a stock for the FN Mauser(semi-inletted) Check number 726030 Also try Bob's Gun Shop and most any of the aftermarket stockmakers can supply a replica stock...wood only metal will have to be purchased separately check the listings in www.gundigest magazine.com...any of the aftermarket barrel makers can cut a blank to service your rifle already chambered for the .225 Winchester cartridge..or if you go to www.midwayusa.com
and use their Gunsmith Locator service(its free) you can shop for a smith to do your work. Also, You can rent the reamer and headspace gauges and recut the chamber yourself..those tools and a depth micrometer will get the job done BTW the 840 is one of the models in the Model 340 series and many of the parts swap out. In fact the parts list covering your model and the Models 340 shows that(other than caliber specific parts) the only unique parts to the 840E are: The rear sight...rear sight step and the stock with buttplate.