Setting aside that there are some things with which I don't feel comfortable about the quoted value of the scope nor of the deal itself, you made an agreement on things you wanted. It's your deal, not ours. Forget about putting any scope on it and fire using iron sights. DG rifles are reknowned for dislodging scope elements.
My opinion is that if the rifle is a good one you have now a far more useful item than a scope...and I hope your 700 has iron sights. Unless a Khales or Nickel and I had very deep pockets I wouldn't shell out $1700US for a scope. How you had a lot invested in the scope eludes me and that may be motivated to say by self protection. You can buy a top quality scope, Czech/Austrian for around $500 US....now that doesn't mean any or every $500 US scope is as good as the type I speak of...but when you pay for a very expensive scope, keep it for life if it is really any good as opposed to being 'expensive'..and I mentioned two good ones...neither of which is my "$500 Austrian scope'..
Rifles when retailed have to cover costs, holding costs and profits..as well as a warranty.Your vendor may have none of those or all of them, but you haven't mentioned warranty. Always ask for Warranty an be cear in writing on what it is an the conditions.
If i have one niggling concern its that such a swap could be for a defective rifle that he couldn't shift, and without any criticism at all, purely geniality, it sounds as though your experience with firearms might not be profound. I would have that rifle checked over by a gunsmith as quickly as possible.
Americans are not noted for selecing European calibres ..for reasons some sensible and some insensible. In thinking that all good starts and finishes at the statue of liberty they miss a great deal
The 8mm and the 9.3 x62 were superb rifles...my 1906 9.3 obenendorf is still in S Africa and it's just beautiful. It's close equivalent to 375. The 190.75 cartridge however doesn't make the grade.
Calibres are largely created by amunition makers competing for proprietary ammo sales ...and like printers the money is in the ink...are the cartridges...
A vast variety of calibres have been churned-out all with dedicated clan followings. There are probably 6 calibres and perhaps even 3 who's cartridge loads as a gropu will serve all purposes and the rest could be scrapped. The 243 for example is across the board an outstanding calibre. The 375 is anothe though I'd choose a 416 Rigby. In fact over 243 and any of the British calibres of 404, 416 and 470 cover everything.
A dangerous game addict and risk-taker might want a 500NE . Of all those I'd choose 416 Rg. 470NE (or a 458Lott) and a 500 NE, unless really strong enough and with need enough for a 600 or 700. One can go around this all day for years...and people have done so.
For various reasons including cartridges and costs .22 0r 222 or similar derivative, a 243 or 270, a 375,would cover most needs up to DG.. Wildcat cartidges limit purchase sites and are invariably expensive. Once you head into 404 416, 458 Lott, (460 WN is in there but there are other cartridges..) 470, 500, 505, 600, you are talking about very expensive ammunition...you don't learn to shoot on those calibres unless you have quite a disposable income. 100 rounds should last years.
So getting back to the 416, Remingtons are ok not my choice I'd go CZ, but a good enough rifle. It's too expensive for cartridges to be learning long range shooting unless you have great ability. It's one of the all time great calibres for DG hunting with seemingly a sort of 'perfect combination' of traits. It will kill anything so long as the shot is well placed..it can drop an elephant in its tracks or a buffalo, but calibre is only one aspect of that. When it comes to dropping a DG to save yourself when you may not have ice in your veins a 470 or 500 double is your gun...or someone else holding one to protect you...but that's up in fairyland for the vast majority of shooters.
Your Remington is one of 3 or 4 cases in that DG calibre. The Brits had these issues sorted out pretty while the Americans were resting on the 45.70. The large case calibres were an easier shoot than say my 458Lott. and 22 inches is about as much as one wants when on the bushveldt...so a double 416 is a handy rifle (when they have rifling grooves insie he barrel, creating a sort of gyro for stalising the elongated bullet...whereas guns uses round ammuniton. .... they are rifles, not guns) If I had one choice on effectiveness, cost of ammo I'd go 416. For plains game 375 is adequate. Retail for ammo for my Lott is $1000/100! you can buy 416 better than that, you can buy 458 Magnum for less...maybe 600/100 retail.
If your 416 turns out to be a good gun and well kept forget prices...you got the better part of the deal....and a fine rifle and calibre. I'd call what most think of as 'distance' shooting ...500-1000yards as absolutely pointless with a 416 Rem. in fact I'd call it just plain stupid...because it isn't that kind of rifle design...or cartridge design
If you use targets from say 50-150metres (or yards) and can shoot it consistently accurately you have the calibre working as intended...it's pretty flat to 150metres (say yards if you wish) and consistently raise the rifle sight and shoot accurately in one motion the you have achieved something useful and skilful. If you want to shoot 'distance' buy a rifle flat for distance..the 416 is a dangerous game at close quarters shooting or at food gathering up to 150 metres for smaller game.
In the future obvous as it is...know the value not of 'brand x' but YOUR particular 'brand x' before doing...and make sure you have a competent check of what you are trading-for so that you are dealing in reality.Voila