ation ▁of ▁the ▁gas ▁pressure ▁( as ▁well ▁as ▁the ▁imp ending ▁end ▁of ▁World ▁War ▁II ) ▁led ▁to ▁the ▁can cellation ▁of ▁this ▁order . ▁Despite ▁this , ▁Sa ive ▁( who ▁had ▁returned ▁to ▁Li ège ▁shortly ▁after ▁its ▁liber ation ▁in ▁September ▁ 1 9 4 4 ) ▁continued ▁work ▁on ▁the ▁rif le , ▁and ▁final ized ▁the ▁design ▁for ▁the ▁F N - 4 9 ▁in ▁ 1 9 4 7 . ▁ ▁The ▁F N ▁Model ▁ 1 9 4 9 ▁is ▁not ▁am mun ition ▁specific ▁since ▁it ▁does ▁have ▁an ▁adjust able ▁gas ▁port ▁or ▁val ve ▁to ▁adjust ▁the ▁rif le ▁to ▁various ▁prop ell ant ▁and ▁project ile ▁specific ▁pressure ▁behavior , ▁in ▁which ▁the ▁gas ▁port ▁can ▁be ▁adjust ed ▁with ▁a ▁special ▁w rench . ▁ ▁This ▁also ▁requires ▁removing ▁the ▁upper ▁forward ▁hand guard ▁for ▁the ▁adjust ment . ▁ ▁Production ▁lifetime ▁▁ ▁The ▁contract s ▁for ▁the ▁S AF N ▁ 1 9 4 9 ▁rif le ▁started ▁in ▁ 1 9 4 8 ▁with ▁the ▁first ▁order ▁placed ▁by ▁Venezuela ▁on ▁March ▁ 3 1 , ▁ 1 9 4 8 , ▁delivered ▁exactly ▁four ▁months ▁later . ▁The ▁last ▁production ▁contract ▁of ▁complete ▁rif les ▁was ▁ordered ▁by ▁Indones ia ▁on ▁December ▁ 1 9 , ▁ 1 9 6 0 ▁and ▁delivered ▁by ▁February ▁ 1 9 , ▁ 1 9 6 1 . ▁ ▁Some ▁sources ▁claim ▁pre - production ▁models ▁for ▁demonstr ation