Greetings Sir
That sounds like one of the best reasons to buy one of these classic rifles.
As a military firearms buff for much of my life a few things come to mind.
The inexpensive German and Swedish Mauser's are gone same as the 1903A1 and 1903A3s among other fine old classics.
Out of the current remaining models and types that have been imported or are still turning up a few thoughts come to mind and my top three choices are listed below.
Being that these are going to be given as gifts to your sons I would not make a 1938 91/30 or 1944 models my first choice unless budget is a main concern.
The Russian rifles are not in the same league as other milsurps considering all points.
They do cost less than the other military rifles because they made them by the millions often during some hard times and conditions with some examples and some not so good examples showing up.
One has to cherry pick and choose very carefully as accuracy can vary greatly as can bore condition and overall quality of parts and fit and finish.
Even a nice one on its best day is not equal to a Finnish one IMO from all the ones I have seen.
THE best Mosin Nagant rifles IMO and are the Finnish 28-30 and M-39 if they did not meet a certain standard of accuracy and quality during the different inspections they were either fixed or rebuilt until they did.
Most of the Finn rifles were rebuilt by Sako Valmet or Tikka (91/30s)
Until recently these rifles were sorted and stored being held in reserve they were also used for training until not too long ago some have had little use others never were issued others have seen combat during the Continuation War and then there are the sneaks ones built in the late 1960s.
The numbers of Finnish rifles produced never equaled the millions of each model that the Russian made and issued.
They are rapidly gaining collector rifle status as the old Springfield's and Swedish Mauser did years ago.
A good .303 Enfield SMLE MK III or No I or II MK IV would also be on my list they are one of the best of the bolt action battle rifles they may not have the best accuracy but they are one of the fastest bolt actions with allot of history behind them.
Rugged reliable and very fast to shoot using the Walbridge method of operating the bolt.
Look for these to go up in price and scarcity as countries who used to allow its citizens to own them continue to cut them up or ban them.
The best years of the inexpensive SMLE & Enfields are behind us at least so it seems so get one while you can.
Another classic well made surplus rifle is the Schmidt Rubin Swiss K 31 these are a straight pull rifle and are among some of the finest rifles built IMO I would not want to see what a US company would charge to manufacture one exactly like it today the cost would be way up there.
The only drawback to owning one is it can be hard to find ammunition and it can be spendy when you do but that is changing somewhat.
It is THE fastest bolt action pull bolt back push bolt forward thats it!
It has out of the box accuracy equal to many current hunting rifles and its built like a Swiss watch and like the Finnish Mosin's only limited numbers were built so expect prices to go only higher.
I know your sons will appreciate whatever you give them.
Best of luck