I would like to give my answer to fellow member Huvius.
First about Mahillon (in later years La Maison du Chasseur-Mahillon). Mahillon was a big hunting shop in Brussels, Belgium. They were not really makers. Mahillon ordered guns and sold these under their own name. A bit like Army and Navy, Rodda and such. Most were made by top Belgian makers (Francotte and others) but British and German made Mahillons are also sometimes encountered. Mahillon marketed quality stuff only, and they have an excellent reputation in Europe. I live in Belgium and my local shop has a mint Mahillon mauser bolt action (cal 8x68S) for sale that makes me drool… Conclusion: your Mahillon is a very nice Belgium made rifle from a respected firm.
“No name Mausers” (and also ‘no name’ double rifles and shotguns for that matter) are very common in Europa. These are difficult to judge. Sometimes an educated guess can be made, based on style, proofmarks and such. Or you have to know what to look for. If for example you buy a double rifle with no name (or an obscure name) at a low price, and find a small AF stamp on the barrels and action, you can start a dance of joy. That little stamp means Francotte, one of the best makers ever. With ‘no name guns’ overall quality, condition and reliability (check every bolt action for reliable feeding at high speed!!) are the deciding criteria. With a bit of luck you may find a genuine gem for little money.
Remember that some ‘common’ manufacturers made very good bolt actions. The Herstal made FN and FN-Browning commercial mauser sporters for example are really top quality. I also have this British Parker-Hale in .404 Jeffery that works like a charm. You mention Joel Dorléac. He wrote an interesting article in the French magazine ‘Armes the Chasse’ about this very question: wich is/was the best bolt action in the world? For Joél Dorleac the answer is simple: the Czech Brno rifles. How right he is! I own several. My latest acquisition is a 1967 Brno ZKK 602, .358 Norma Magnum caliber (mint condition, 450 euro) You can not buy a better rifle anywhere ( here we talk precision, reliability, quality of barrel, steel etc) at any price. A top name London bolt action with extra fancy wood and all the trimmings will cost you a tremendous amount of money, but it will NOT be a better rifle. In fact the Brits never made a peep sight as good as the Brno collapsable bridge peep. The fact that Brno rifles were by far the cheapest (money-wise) on the European market probably created this general ignorance concerning its real qualities.
Greetings
Sus