Nearly all my custom rifles are made on Mauser actions. And all are accurate with some being freakishly accurate.
The FN Mausers made in the 40s, 50s and 60s were excellent rifles but you must remember the barrels were made at that time too. Some were OK, some very good. The barrel making capability of today is WAAAAAY out in front of most commercial manufacturing of the 60s. So asking "Remington VS Mauser" is not really the right question.
The actions don't shoot.
The barrels shoot!
So given the same barrel quality in both guns, they would be equally accurate. If you look at a M700 of say 1990 vintage and compare it to an FN Mauser of say `950 vintage, even money says the Remington will out-shoot the Mauser, because the 1990 barrels are made to tighter tolerances then the 1950 barrels overall. There are exceptions on both sides, but they are just that.........exceptions.
The Remington has a faster lock time, but that feature is a bit over rated. If your squeeze is straight and to the rear and you have good form, lock time is not much of a factor in accuracy. It can be a slight edge for bench rest shooters, but even then we don't see all the records set or broken with guns with "the fastest lock time"
The Mauser is far superior in it's extractor, and in it's bolt handle (one piece instead of being soldered on)
The Remington triggers are a good design, but often made from low grade materials which is why they have had so much legal trouble with them, over and over and over. Mauser military triggers can be re-worked for decent pulls, but it's easier to replace them with a Timney or some such after market trigger for most men. To be fair, if we replace the Mauser trigger with an aftermarket trigger we'd have to give the same trade to the Remington.
The controlled round feed is the gold standard in all bolt action everywhere in the world. Here the Mauser, (and the copies of it's extractor, 1917 Enfield, M70 Winchester, M77 Ruger Mk2 and so on) leave the Remington in the dust.
In fact, as a gunsmith with about 50 years of experience, I can tell you that the Remington M721, M722, M700 and M600/660s all suffer from the weakest extractor ever put in any bolt gun anywhere at any time. That's not to say they are all failures, but just to say everyone eases are stronger. I have replaced more Remington M700 extractors in my 50 years then all other actions of center fire rifles combined.
But these are reliability issues, not accuracy issues.
Comparing a full custom build made on a Mauser to a factory Remington is not a valid comparison. That's because you get to select a high grade barrel one at a time on any custom rifle, where as the production rifle has a production barrel in it. MOST Remington are very accurate. I have had to work on a LOT of Remington for a LOT of reasons, but barrel quality is not often one of those reasons.
