battle-hardened russian

• обстреля́вший

  having fired upon, having shelled, that fired upon, that shelled

  battle-hardened, seasoned (in combat), combat-experienced

• поню́хавший

  experienced, battle-hardened

• прокалённый

  calcined, roasted, heated through

  hardened, seasoned, experienced, battle-hardened

• стре́лянный

  shot, fired

  experienced, seasoned, battle-hardened