A batch of 15 police vehicles made ‘‘bullet-proof’’ by the Ordnance factory in Medak has failed mandatory tests.Tripura police have written to the Ministry of Home Affairs that bullets from SLRs easily pierced the vehicles during test firing. After the failed tests, the Tripura government has decided to pull out the entire batch. An additional Rs 5 lakh was spent on each Maruti Gypsy to make it bullet-proof.The complaint from Agartala, sent on May 13, states: ‘‘These vehicles are unfit for operational duties. please take up the matter with the Ordnance Factory, Medak for arranging immediate replacement of all 15 bullet-proof Maruti Vehicles with proper bullet-proofing at their own cost.’’While MHA officials said they did not want to comment on the lapse, A K Bhattacharya, under secretary with the government of Tripura, said the State Government had taken serious note of the failed results.‘‘We have since been informed by the MHA that the matter has been taken up with the Ordnance factory and that the entire batch of 15 vehicles will be fitted with fresh bullet-proofing,’’ he told The Indian Express.He pointed out that these vehicles were part of the Special Assistance given by the Centre to Tripura. The report he sent to the MHA showed that while the rounds fired (at a distanec of 10 metres) from an AK-47 rifle made dents at striking points, the SLR bullets ripped through.Earlier, following a similar instance of bullet-proof steel manufactured by SAIL failing test-firing, the MHA had given permission to the ordnance factories to import the steel and centralise dispatch of the vehicles to terrorist-effected states from Medak.