Abstract: When the parametric methods are used to estimate the firing reliability of explosive initiator， the bias in estimation of the standard deviation often makes the evaluated results excessive. When the nonparametric methods are used to estimate the firing reliability of explosive initiator，the test sample size is usually large. A small sample reliability assessment method for firing reliability of explosive initiator based on the mean of sensitivity distribution is proposed by using the stress-strain interference model and combining the parametric methods with the nonparametric methods. The proposed method only uses the mean of sensitivity distribution to convert the verification test at the working stimulus to the verification test at the low stimulus at a constant confidence level，thereby greatly reducing the test sample size. The large sample run-down method and the proposed small sample method are used to conduct the comparative tests on a certain type of stab detonator and a certain type of fuse head. The result shows that the reliability evaluation results of the two methods are consistent. The proposed assessment method is reasonable and can be applied to the reliability assessment of mechanical and electric explosive initiators.

Key words: explosiveinitiator, firingreliability, meanofsensitivitydistribution, smallsample, stress-straininterferencemodel