I am going to expand on this fine disertation on fixing a duffle cut stock with a small caution....
The example show by Hambone seems to have had the duffle cut made to the stock with a very thin bladed saw, maybe a hacksaw for example. This thin saw blade removes a very thin amont of wood. Essentially when cutting wood like a stock, you permanently remove the thickness of the blade from the stock.
Some GI's used hacksaws to cut the stocks, others used saws intended for cutting firewood. A duffle cut done with a thin blade will go back together well, as in the example above. A duffle cut done with a thicker bladed saw, will remove more wood. I have seen some duffle cut stocks missing almost 3/16 of an inch of wood.
If you repair a thicker cut like that, and try to butt the two pieces of stock together flush, it may set the front band back too far to look original. So expanding on what Hambone said, watch your wear patterns on the barrel from the bands carefully, and even check it against an uncut stock if need be to make sure you get the overall length just right. Discovering you put it back together too short after it is all dry and set really bites. Very nice thread on this Hambone!!
Bill ; The devil is in the detail. Hambone and I myself have been doing this for some years now. Gew98's are a good bit harder to repair than the more meaty 98k stocks.
If you noticed the majority of WW1 era duff cut gew98's exhibit some severe angle cuts ( 22.5 / 45 degree for example ). At the time of the end of the shooting war US engineers were in some major barracks and supply building construction. It's not short leap to see GI's asking these guys with mitre boxes handy to do some cuts for the sake of protability. Somewhat same for WW2. These saws as noted do take alot of meat ( kerf ).
Anyhow unless some butcher has tried to half arsed repair an old duff cut - like mating the surfaces and notching back the handguard to mate and shortening the band spring. I have encountered many rifles with frigged handguards and the like as someone was too lazy to do the repair with all considerations. I myself use a fiberglass resin to fille kerf dimensions -it fills in good , has strength and can usually be matched to general wood color well. As for the screws I use a much more coarse thread ( more akin to a sheet metal screw and use steel - brass does bend too easily ). I also imbed the screws in the forend peice first the night or more before assembly to the stock.
Anyhow if you take this serious as guys like Ham and myself...the I's are dotted and the Tee's are crossed.