the answer was posted 2 years ago, currently buying the next modification of the turret will cost you the same as micro-upgrading your turret to the next modification.
- Suppose you fully micro-upgrade Railgun m2, then you can claim railgun m3 for free but ONLY when you have reached the rank of marshal as this is the unlocking rank of railgun m3. I hope this clears your doubt. Similarly if you have fully micro-upgraded your railgun m1 then you will get railgun m2 for free once you reach First Lieutenant as this is the unlocking rank of the turret. For more help: https://en.tankiwiki.com/Ranks
http://ratings.tankionline.com/en/user/mjrocks05/ [Personal message me]
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