I picked up the Dumoulin rifle this morning and it really is beautiful, about 90-95% condition. It's marked as follows:
H. Dumoulin Milmort-Liege Made in Belgium
Serial number matches on barrel and action 34xx
Caliber marked as 338
Jewelled bolt and magazine follower
FN commercial action

Full length Mannlicher stock out of a nice bit of what looks like French Walnut-some fiddleback in the butt and nice dark streaking-single recoil bolt, shadow cheekpiece

Checkering very well done about 22-24 LPI
White line spacer on grip cap and recoil pad
2 position side safety (a little moe elegant than normal)
Two screws where a long front sight could have been, no holes or any indication of a rear sight though.

So what do I really have? One of my books has a little info on Ernest Duloulin and you guys helped a bit more, I have nothing on H. Dumoulin though.
Thanks for any info,

Try this link. Maybe they can give you some info:
Belgium