Mate, no need to crimp however, it can drop your ES by slightly rounding the neck tension. I do for my 556 but really only because I dont want any feed issues and they things are also FL sized for that reason.
I would start by mimicking the length of a standard round (as it will be mag fed) and sort the load out first, then, if you fancy it you can tinker with the OAL but thats up to you.
The reload swiss powders are a bit missunderstood really. RS50/TR140 is NOT a direct replacement for N140, it is a tad slower but shoots well.
RS52 is less spitefull and the quick test I did in my 556 shows it to shoot better than the other powders I have tried (IMR4895/Wildboar/N140). My old FTR lot swear by it and depending where you get it the price is comparable and its obtainable. It might go well in the Dagunov with a heavy old bullet.
However, do (when you get into it) establish several loads that work so that if you cant get something.....
No real need to purchase a loading manual these days as the things are constantly being updated and most manufacturers either publish the data on line or will send data to you....or find a friend with quickload. Most if not all are sensibly conservative so you should be fine.
Talking of parts and saving money, the Murom/Muron/PMC/Wolf/Moron primers are good value and work well (the red standard ones do in any event) from Myles Robertson at the NSC or HPS.
Enjoy, take it easy and you wont damage anything
